LIQUID DISPENSER

Abstract: There is provided a dispenser for delivering aliquots of a liquid product comprising a housing (1) and a disposable refill package which is positioned inside the housing (1) and comprises a collapsible reservoir (2) for the liquid product fitted with a bellow pump (3), whereby the bellow pump (3) comprises a product inlet valve (4) and a product outlet valve (5) and is manually operable via indirect actuating means (10, 11), and whereby the housing (1) is provided with a narrow opening (9) into which a correspondingly shaped portion of the bellow pump (3) located near the outlet valve (5) thereof, can be detachably secured, characterised in that the bellow pump (3) is equipped with a discharge tube (8) having an internal flow channel of which the diameter at the outlet is at least 1.2 times larger than at the inlet.

Description: LIQUID DISPENSER Technical field of the invention The present invention is concerned with a dispenser of the kind for delivering aliquots of a liquid product from a reservoir by means of a pump which is manually operable. Such dispensers are often used in washrooms etc. for dispensing small amounts of a liquid soap product for hand washing pur¬ poses. BACKGROUND AND PRIOR ART Various dispensers of the above-indicated kind have been described in the literature. For example, the US-patent 4,256,242 (Christine) discloses a liquis soap dispenser comprising a housing, a collapsible bag for holding the liquid soap product and an operating lever or handle for actuating controlled amounts of soap from the bag. The collapsible bag is connected to an outlet by means of a flexible conduit which comprises a pump. These known types of dispensers offer hygiene and ease of handling for the user. However, one problem with this kind of dispensers resides in the fact that only a small amount of liquid soap may be dispensed at the time due to the limited capacity of the peristaltic type of pump applied. The amount is usually not more than 0.5 to 1 ml. Another problem which has been encountered with this type of pump is related to the way the pump operates: after the pump has been actuated the pump tubing recovers to its original shape and thereby sucks in liquid product for the next shot. This sucking action of the tubing is directly related to the memory properties thereof which could decline depending on the material of the tubing and the operating time of the pump. As a consequence, the dosage of the pump per shot could decline. In order to overcome this problem, it has been proposed in the British patent application 2 103 296 to provide the dispenser with a bellow pump fitted with an external spring. As a result of this spring, the recovery properties of the bellow pump can be optimized to such extent that even liquid products of high viscosity can be satisfactorily applied in this dispenser. For reasons of easy handling, the dispenser disclosed by this document comprises a disposable refill which comprises a reservoir and the bellow pump. However, the disclosed dispenser is a rather specific one in that it can only be activated by electromagnetic means. Another type of dispenser also comprising a disposable refill package including a reservoir fitted with a bellow pump, is disclosed by 094/07113. The dispenser disclosed by this document can be simply constructed, is manually operable and can be easily refilled. However, it has been observed that the discharge tube of the bellow pump present in this dispenser can clog with liquid products which are prone to dry out in use. As an example of such products, thickened alcohol gels may be mentioned. It has now surprisingly been found that this problem can be overcome by applying the dispenser of the present invention. Definition of the invention Accordingly, the present invention provides a dispenser for delivering aliquots of a liquid product comprising a housing (1) and a disposable refill package which is positioned inside the housing and comprises a collapsible reservoir (2) for the liquid product fitted with a bellow pump (3) , whereby the bellow pump comprises a product inlet valve and a product outlet valve and is manually operable via indirect actuating means (10,11), and whereby the housing is provided with a narrow opening (9) into which a correspondingly shaped portion of the bellow pump located near the outlet valve thereof, can be detachably secured, characterised in that the bellow pump (3) is equipped with a discharge tube (8) having an internal flow channel of which the diameter at the outlet is at least 1.2 times larger than at the inlet. The present invention also provides a disposable refill package suitable for use in a dispenser according to the invention, comprising a collapsible reservoir (2) filled with a liquid product and attached thereto a bellow pump (3) provided with a narrow portion (9) which can be detachably secured into a correspondingly shaped opening located in the housing (1) of the dispenser, characterised in that the bellow pump (3) is equipped with a discharge tube (8) having an internal flow channel of which the diameter at the outlet is at least 1.2 times larger than at the inlet. Detailed description of the invention Since the internal diameter of the discharge tube of the bellow pump is wider at the outlet than at the inlet, said tube widens in the direction of liquid flow. As a consequence, any plug of dried out liquid product present inside the tube breaks up easily whenever the dispenser is operated after a long stand-still period. Furthermore, in order to produce a discharge tube of the present invention a standard discharge tube needs to be modified by removing material therof. As a result, the discharge tube becomes more flexible, thus adding to the ease, by which any blockage present therein can be removed. In order to secure smooth flow of liquid, in particular liquid of increased viscosity, the internal diameter of the discharge tube at the inlet thereof is preferably larger than l mm. Furthermore, the internal diameter at the outlet of the discharge tube is preferably 1.5 times larger than at the inlet. On the other hand, the discharge tube of the present invention desirably comprises a flow channel having an internal opening with a diameter of less than 3 mm. The advantage of this type of discharge tube is that the flow rate of the liquid product flowing out of the bellow pump during each dose, is increased due to the narrow internal opening, which proved to have a self-cleaning effect on the flow channel. The possibility of bacterial growth entering the valve is thereby further diminished. Preferably, the discharge tube according to the invention is made of plastic material such as polyethylene, polypropylene, and PVC. Also, the reservoir which is part of the disposable refill package applied in the dispensing system of the present invention, is preferably made of these types of plastic material. For reasons of convenience and in order to reduce the risk that the liquid to be dispensed is contaminated when installing a new refill, the refill is made of one piece. The bellow pump to which the discharge tube is attached, comprises a liquid inlet valve and a liquid outlet valve which are respectively closed and opened by manually operable actuating means during each dose. Immediately after each dose, when the liquid outlet valve is closed, the liquid inlet valve is opened by the suction action of the bellow when it recovers to its original position. As a result, full liquid communication with the reservoir is achieved and the internal volume of the bellow pump is refilled by liquid sucked in from out of the reser¬ voir. As a consequence of this action of the liquid inlet and outlet valves present in the bellow pump during and im¬ mediately after each dose, no air can enter the internal volume of bellow pump and reservoir and the risk of con¬ tamination of the liquid to be dispensed is minimized. The material of the bellow pump is preferably such that the suction action of the bellow pump is kept more or less constant, also after many dosages have been done. When the dispenser is used for dispensing more viscous types of liquid, the bellow pump is preferably equipped with an external spring. This spring ensures that constant dosage volumes are obtained during the operating life of the dispenser even with highly viscous liquids because it forces the bellow pump back into its original shape after each dose. In order to ensure that the refill package is easily and securely fitted in the housing of the dispenser, the housing is provided with a narrow opening into which a correspon¬ dingly shaped portion of the bellow pump located near the outlet valve thereof can be detachably secured. Furthermore, this narrow opening ensures that only refill packs containing the desired type of liquid product will be mounted in the dispenser, because other packs containing different products simply will not fit. This narrow opening is desirably in the form of a slit having a width of less than 5 mm, preferably less than 2 mm. For reasons of ease of handling, the dispenser of the present invention is equipped with manually operable indirect actuating means. These may practically comprise a push rod which is coupled to the bellow pump via a tilting table. The internal volume of the reservoir gradually decreases when liquid product is taken out and dispensed. When the reservoir is pumped empty, underpressure is created and, as a conse¬ quence, the bellow of the pump will be kept in a collapsed position. The resulting reduction in length of the bellow pump can be used as an empty pack indicator. Dispensers comprising a bellow pump with a dosing capacity of from about 0.1 to 10 ml are very suitable for use in washrooms. This type of dispensers having a dosing capacity in the mentioned range can be made much more compact than dispensers with peristaltic or plunger pumps with the same dosing capacity. The invention wil now be better explained by way of the preferred embodiment shown in the accompanying drawings of which: Figure 1 shows cross-sectional views of a dispenser according to the invention including a housing, a collapsible reservoir and a bellow pump, whereby the bellow pump is not activated (a) respectively activated (b) ; Figure 2 shows a cross-sectional view of the bellow pump, including an inlet and outlet valve, and a discharge tube. In Figure 1, a housing (1) is shown comprising a refill package which comprises a reservoir (2) and a bellow pump (3) . The dispenser can be manually operated with indirect ac¬ tuating means comprising a push rod (10) which is coupled to a tilting table (11) which in turn is connected to the bellow pump (3) . As shown in Figure 1, a narrow portion (9) is connected to the bellow pump (3) which portion is used for securely positioning the refill package in the housing of the dispenser. Furthermore, the bellow pump is provided with a discharge tube (8) which comprises a flow channel having a narrow internal opening of which the cross-section at the outlet is wider than at the inlet of said discharge tube. It can also be noticed that an external spring (12) is present between tilting table (11) and the housing. This spring ensures that constant volumes are dosed even when applying high viscosity liquids. Figure 2 shows a bellow pump provided with an inlet valve (4) , an outlet valve (5) and a bellow section (6) . Because the internal volume of the bellow pump contains the liquid to be dispensed during the next dose, the bellow pump functions as a type of dosing section. It can further be seen that the discharge tube (8) of the bellow pump comprises an internal flow channel of which the diameter widens from 1.6 mm at the inlet to 2.5 mm at the outlet, thus ensuring favourable operation of the dispenser even when using viscous liquids which are prone to dry out during stand-still periods. It is emphasized that the dispenser shown in the Figures illustrates only a preferred embodiment of the invention and that various constructional alternatives will be immediately evident to the man skilled in the art, without departing from the scope of the present invention.

Claims: CLAIMS 1. A dispenser for delivering aliquots of a liquid product comprising a housing (1) and a disposable refill package which is positioned inside the housing and comprises a collapsible reservoir (2) for the liquid product fitted with a bellow pump (3) , whereby the bellow pump comprises a product inlet valve and a product outlet valve and is manually operable via indirect actuating means (10,11), and whereby the housing is provided with a narrow opening (9) into which a correspondingly shaped portion of the bellow pump located near the outlet valve thereof, can be detachably secured, characterised in that the bellow pump (3) is equipped with a discharge tube (8) having an internal flow channel of which the diameter at the outlet is at least 1.2 times larger than at the inlet. 2. A dispenser according to claim 1, wherein the discharge tube (8) has an internal flow channel of which the diameter at the outlet is at least 1.5 times larger than at the inlet. 3. A dispenser according to claim 1 or 2, wherein the discharge tube (8) has an internal flow channel of which the diameter at the inlet is more than 1 mm. 4. A dispenser according to any of claims 1-3, wherein the discharge tube (8) has an internal flow channel of which the diameter is less than 3 mm. 5. A dispenser according to any of claims 1-4, wherein the bellow pump is provided with an external spring (12) . 6. A dispenser according to any of claims 1-5, wherein the narrow opening in the housing (1) is in the form of a slit having a width less than 5 mm, preferably less than 2 mm. 7. A dispenser according to any of claims 1-6, wherein the bellow of the bellow pump is kept in a collapsed position as a result of the underpressure created when the reservoir is pumped empty. 8. A dispenser according to any of claims 1-7, wherein the bellow pump has a capacity of from about 0.1 to about 10 ml. 9. A disposable refill package suitable for use in a dispenser according to claim 1, comprising a collapsible reservoir (2) filled with a liquid product and attached thereto a bellow pump (3) provided with a narrow portion (9) which can be detachably secured into a correspondingly shaped opening located in the housing (1) of the dispenser, characterised in that the bellow pump (3) is equipped with a discharge tube (8) having an internal flow channel of which the diameter at the outlet is at least 1.2 times larger than at the inlet.

Inventors: BUNSCHOTEN GERRIT KLAAS, ELLIS SIMON RICHARD, VREEMAN JAN AREND, BUNSCHOTEN, GERRIT, KLAAS, ELLIS, SIMON, RICHARD, VREEMAN, JAN, AREND
Applicants: UNILEVER NV, UNILEVER PLC, UNILEVER N.V.
Application year: 1996
Main classification: A47K5
IPC codes: A47K5