Background of the Invention Numerous devices have been devised to dispense liquids and other materials from a bulk container in a controlled manner. For example, US 5,135,139 (assigned to Creanova AG) discloses a cover for opening and closing a container. Rotation of a cap component causes it to be axially displaced forming an opening through which the contents of the container may be dispensed. US 4,684,046 (assigned to Realex Corporation) discloses a dispenser which also operates on the principle of axial or telescopic displacement of components. US 3,357,605 (assigned to Formold Plastics, Inc) discloses a cap which is rotatably mounted on the neck of a container which operates by aligning an aperture in the cap with an offset wall portion in order to facilitate flow of material from the container. No provision for the dispensing of fixed volumes is made. US 4,961,521 (Ronald E.

Eckman) discloses an adjustable metering dispenser which operates on the basis of rotational alignment of apertures. However, this device requires two independent rotation operations in order to dispense a single volume of material. US 4,632,362 (assigned to Waddington & Duval Ltd) discloses a rotating spigot tap which operates on the basis of aligning two apertures by the relative rotation of the spigot within a fixed housing. No provision is made for the dispensing of fixed volumes.

None of the prior art devices referred to above combine the ability to repeatably dispense fixed volumes with a simple one step dispensing operation. The devices described above typically require multiple steps or operations to dispense fixed volumes and/or involve complex mechanisms to achieve the desired effect.

It is an object of the present invention to provide a dispenser suitable for repeatably dispensing fixed volumes of a liquid or other flowable material and which is easy to install, operate and maintain.

Brief Description of the Invention In its broadest aspect the present invention provides a dispenser for dispensing a fixed volume of material from a bulk container, the dispenser comprising: a housing and a reservoir unit; the housing having an inlet and an outlet, the inlet being adapted to communicate with the bulk container; the reservoir unit having one or more internal baffles defining a plurality of chambers, each of said chambers having at least one port communicable with the inlet and/or the outlet; wherein the reservoir unit is adapted to be displaced within the housing; and wherein displacement of the reservoir unit within the housing facilitates progressive or reciprocal movement of the chambers between filling and emptying positions such that when a first chamber is in a filling position, a second chamber is simultaneously in an emptying position.

Preferably, the housing is cylindrical and the reservoir unit comprises a drum adapted to rotate within said housing, wherein rotational displacement of the reservoir unit within the housing facilitates the progressive movement of the chambers between filling and emptying positions.

Alternatively, the dispenser may be configured such that translational displacement of the reservoir unit within the housing facilitates the movement of the chambers between filling and emptying positions. Biasing means may be provided to secure the reservoir unit within the housing in suitable manner.

Each chamber may comprise a single port, communicable with both the inlet and outlet in succession. (In this case the port is referred to below as the chamber port or simply the port.) Alternatively, each chamber may comprise a plurality of ports, for example each chamber may comprise a first port communicable only with the inlet and a second port communicable only with the outlet. (In this case the first chamber port is referred to as the chamber inlet and the second chamber port as the chamber outlet.) Any such arrangement is suitable provided that displacement of the reservoir unit within the housing facilitates progressive or reciprocal movement of the chambers between filling and emptying positions such that when a first chamber is in a filling position, a second chamber is simultaneously in an emptying position and provided that there is no possibility for material to flow into and out of a given chamber at the same time (which would frustrate the invention).

Optionally, the housing and the reservoir unit may define a separate filling chamber located between, and communicable with, the inlet and the reservoir unit.

Optionally, venting means may be provided in order to facilitate filling and emptying of the chambers.

The dispenser of the present invention allows fixed volumes of material to be dispensed and is simple to operate and maintain having a minimal number of moving components. A single action displacing the reservoir unit within the housing causes a defined, predetermined volume of material to be dispensed.

Description of the Drawings The present invention will be described in further detail having regard to the accompanying drawings in which: Figure 1 is an exploded view of a first embodiment of the invention; Figure 2 is a schematic side elevation of the embodiment shown in Figure 1 illustrating the chambers of reservoir unit and the simultaneous filling and emptying of respective chambers; Figure 3 is an exploded view of a second embodiment of the invention; Figure 4 is a side elevation of the external aspects of a third embodiment of the invention; Figure 5 is a side elevation of a reservoir unit according to the third embodiment; Figure 6 is an end view of the reservoir unit shown in Figure 5; Figure 7 is an exploded view of the housing and reservoir unit of the third embodiment shown in Figures 4 to 6; Figures 8a and 8b are schematic views of a fourth embodiment of the invention highlighting the filling and emptying positions of a single chamber; Figure 9 is an exploded view of a fifth embodiment; Figures 10a and 10b are schematic views of a sixth embodiment of the invention showing the filling and emptying positions of a single chamber.

Figures 11a and 11b show a seventh embodiment of the invention which is based on translational, as opposed to rotational, displacement of the reservoir unit within the housing.

Detailed Description While the present invention is primarily envisaged for dispensing liquids it may be more generally applied to the dispensing of any suitably flowable material including for example powders. The following description while referring specifically to liquids should not be construed as limiting the application of the dispenser of the invention to such materials.

In all but the final embodiment described below the housing is cylindrical in shape and the reservoir unit is in the form of a drum which is rotatably mounted therein. The drum is provided with a number of internal baffles dividing it into a series of fixed volume chambers. In the final, seventh, embodiment described below (with reference to Figures 11 a and 11 b) the reservoir unit is displaced in a translational manner within the housing, but the same effect of simultaneous filling and emptying of respective chambers is maintained.

Turning now to Figures 1 and 2, the dispenser depicted comprises: a housing 10 having an inlet 14 and an outlet 16, a reservoir unit 20 adapted to fit into the housing 10 and divided into two or more chambers 27 each of which chambers 27 defining at least one port 29 communicable with the inlet 14 and/or the outlet 16 and means (not shown) for effecting rotational or translational displacement of the reservoir unit 20 within the housing 10; wherein said displacement facilitates progressive or reciprocal movement of the chambers 27 between filling and emptying positions in such a manner that when a first chamber is in a filling position, a second chamber is simultaneously in an emptying position.

In this first embodiment, the reservoir unit 20 comprises a drum adapted to fit into the housing 10 and divided into chambers 27 by baffles 28, each of said chambers 27 defining a port 29 communicable with both the housing inlet 14 and the housing outlet 16 in sequence. Rotation of the reservoir unit 20 within the housing 10 facilitates progressive movement of the chambers 27 between filling and emptying positions in such a manner that when a first chamber is in a filling position, a second chamber 27 is simultaneously in an emptying position. (In Figure 2 the flow of liquid into and out of respective chambers 27 is indicated by arrows.) The housing inlet 14, housing outlet 16 and the (chamber) ports 29 are all preferably defined by (and formed in) curved surfaces of the dispenser components. This has the advantage of

optimising the seal between the housing 10 and the reservoir unit 20, thus minimising leakage.

Preferably the housing inlet 14, housing outlet 16 and chamber ports 29 are located substantially midway along the (axial) length of the housing 10 and reservoir unit 20 respectively. Such a configuration maximises the wall area either side of the opening/port in question and helps to reduce leakage between the housing 10 and the reservoir unit 20.

In this preferred embodiment, the housing 10 is cylindrical and the reservoir unit 20 is a drum mounted rotatably therein; the drum contains a number of radial baffles 28 which define a plurality of chambers 27 within the drum; each chamber 27 defines a single port 29, which chamber port is communicable with both the housing inlet 14 and the housing outlet 16, depending upon the orientation of the drum within the housing 10, and the housing inlet 14 and housing outlet 16 and chamber ports 29 are all defined by (or located on) curved surfaces.

In the embodiment shown in Figures 1 and 2 the internal baffles 28 extend radially from the centre of the reservoir unit 20. This radial arrangement of baffles 28 divides the internal volume of the drum into a plurality of wedge shaped chambers 27. In the second embodiment shown in Figure 3 the drum is divided into two chambers by a disc shaped baffle 28 located along, and substantially perpendicular to, the rotational axis of the drum. In either case rotation of the reservoir unit 20 facilitates filling and emptying of each chamber by sequentially aligning the port 29 of the each chamber with the inlet 14 and then the outlet 16. While the port 29 of a first chamber is aligned with the housing inlet 14, the port 29 of a second chamber is aligned with the housing outlet 16. Thus as a first chamber 27 is filing, a second chamber 27 is simultaneously emptying.

In a third embodiment, shown in Figures 4 to 7, each chamber is provided with a separate chamber inlet 30 and a chamber outlet 31. Such a dispenser comprises: (1) a housing 10, formed by a cylindrical wall 11 which is open at its first end and has a flange 12 at its second end, the cylindrical wall 11 defining a housing outlet 16, and the flange 12 defining a housing inlet 14 adapted to connect to a bulk container (not shown); (2) a reservoir unit 20, adapted to fit into the open end of the housing 10 and to be rotatably fixed therein, having a cylindrical wall 21, a front wall 23 and a back wall 22 and one or more internal baffles 28, said walls 21,22,23 and baffles 28 defining a plurality of chambers 27, each of said chambers 27 having a chamber inlet 30 and a chamber outlet 31; and (3) means 25 for rotating the reservoir unit 20 relative to the housing 10; wherein the housing inlet 14 and housing outlet 16 and each chamber inlet 30 and chamber outlet 31 are positioned relative to each other such

that upon rotation of the reservoir unit 20 within the housing 10 the chamber inlet 30 of a first chamber 27 may be aligned with the housing inlet 14 (while at the same time the chamber outlet 31 of said first chamber is aligned with the housing outlet 16) thus facilitating filling of said first chamber 27; and wherein, upon further rotation of the drum 20 within the housing 10 the chamber outlet 31 of said first chamber 27 may be aligned with the housing outlet 16 (while at the same time the chamber inlet 30 of said first chamber 27 is aligned with the housing inlet 14) thus facilitating emptying of the fixed volume of said first chamber.

In this third embodiment of the invention the relative dimensions of the housing 10 and drum (or reservoir unit 20) may be such that the back wall 22 of the drum 20 abuts the rear flange 12 on the housing 10 forming a liquid tight fit between the back wall 22 and the rear flange 12. Alternatively, as shown in Figures 8a and 8b, an internal dividing wall 17 may be provided in the housing 10, the dividing wall 17, the back of the drum 22, the rear flange 12 and the cylindrical wall 11 of the housing 10 defining a filling chamber 18 which communicates with the chambers 27 in the drum 20 via an aperture 19 (defined in said dividing wall 17) and chamber inlets 30.

As shown in Figures 4 and 7, the dispenser comprises a housing 10 having a cylindrical wall 11 which is capped with a rear flange 12 at one end and is open at the opposite end. The open end of the cylindrical wall 11 defines an edge 13. The rear flange 12 is attached to a housing inlet 14 which defines a thread 15 or has alternative means for attaching the dispenser to a bulk container (not shown). The housing inlet 14 may be fixed to the rear flange 12 in a substantially concentric manner, as shown in Figure 4 or may be off-centre, as shown in Figures 10a and 10b for example.

The cylindrical wall 11 incorporates, or has attached, a housing outlet 16.

With reference to Figures 5 to 7, a drum 20 is provided having a cylindrical drum wall 21, a back wall 22 and a front wall 23. The diameter of the drum 20 is such that it may be inserted inside the housing 10 and fixed therein in a manner which allows rotation of the drum 20 relative to the housing 10 while at the same time providing a liquid tight fit between said drum 20 and housing 10 components. The front wall 23 has a diameter which is greater than that of the drum 23 thus defining a rim 24. The insertion of the drum 20 into the housing 10 is limited by the interaction of the rim 24 and the edge 13. The relatives depths of the drum 20 and the housing 10 are such that when the former is fully inserted into the latter the back 22 of the drum 20 abuts the rear flange 12 in a manner which forms a liquid impervious seal, but which does not prevent rotation of the drum

20 relative to the housing 10. The front 23 is suitably provided with a knob 25 or other means for effecting rotation of the drum 20. The drum 20 contains one or more internal baffles 28 which together with the drum wall 21, back 22 and front 23 define a plurality of chambers 27, Figure 6, of fixed volume. The back 22 of the drum 20 defines a plurality of chamber inlets 30 facilitating access to each corresponding chamber 27. Each chamber 27 also has a chamber outlet 31, Figure 5, defined by the drum wall 21.

In the fourth embodiment shown in Figures 8a and 8b a dividing wall 17 is provided within the housing. In this embodiment the back wall 22 of the drum 20 abuts the dividing wall 17 when the drum 20 is inserted into the housing 10. The dividing wall 17, the back wall 22 of the drum 20, the rear flange 12 and the cylindrical wall 11 of the housing 10 define a filling chamber 18. The dividing wall 17 defines an aperture 19 suitable for transfer of liquid from the filling chamber 18 into the chambers 27 of the drum 20. A fifth embodiment, also embodying the filling chamber principal is shown in Figure 9. In this case the housing 10 has a stepped configuration wherein a first stepped portion of the flange 12a no longer abuts the back wall 22 of the drum 20. The remaining portion of the flange 12b abuts the back wall 22 preventing entry of liquid into a chamber 27 when in the emptying position. A filling chamber is thus defined by the stepped portion of the housing, facilitating filling of one or more chambers which are not in the emptying position.

In operation the dispenser of the invention is attached to a bulk container (not shown) via the housing inlet 14. Where the dispenser is attached to the bulk container by means of a screw thread arrangement 15 it is advantageous for the housing inlet 14 and the housing 10 to be substantially concentric. This makes attachment of the dispenser to the bulk container easier to effect.

In each of the embodiments described thus far the cylindrical wall 11, rear flange 12, front 23, inlet 14 and outlet 16 together define a cavity through which a liquid may flow. The flow of a liquid is controlled by the rotation of the drum 20 relative to the housing 10 as described below. The chamber inlets 30 and the chamber outlets 31 are positioned in such a manner as to facilitate only either filling or emptying of a given chamber 27 at any one time.

Considering a first chamber 27, a filling position is defined when the chamber inlet 30 (or port 29 in Figure 2) is aligned with the inlet 14 so as to facilitate flow of liquid into said first chamber 27.

Under the force of gravity (or the force of any pressure applied to the bulk container) liquid flows

through the housing inlet 14 into the filling chamber 18 if present (embodiment shown in Figures 8a and 8b) or alternatively directly into the chamber 27. In the filling position the chamber's outlet 30 (if separate chamber inlet and outlet are provided) is aligned with the housing outlet 16 and thus flow of the liquid through the chamber is prevented. Upon rotation through a suitable angle the chamber outlet 30 (or port 29) of said first chamber is aligned with the housing outlet 16, defining an emptying position. Simultaneously the chamber inlet 30 of said first chamber 27 moves into a position in which further flow of liquid into the chamber 27 is prevented. Thus aligning the chamber outlet 30 and the housing outlet 16 causes the liquid contained in the chamber 27 to be dispensed.

Where chambers comprise two ports the chamber inlets 30 and outlets 31 are configured such that rotation of a first chamber from its filling position to its emptying position causes the chamber inlet of a second chamber to be brought into a filling position facilitating the filling of a second chamber with liquid while the first chamber is emptying. Further rotation causes the second chamber to be brought into an emptying position while bringing a third chamber into a filling position and so on.

Thus a progression or cycle of filling and emptying of the chambers is provided upon sequential rotation of the drum within the housing. In such a manner a fixed volume of liquid may be dispensed from the bulk container in a controlled and reproducible manner in response to a single rotation operation.

Each chamber may also be provided with ventilation means (not shown in Figures 1-9) to facilitate the venting of air from the chamber as it fills or empties. Separate venting means for filling and for emptying may be provided. Depending on the overall dimensions of the dispenser and in particular the diameters of the housing inlet 14, housing outlet 16 and the chamber ports 30 relative to the volume of the chambers 27, and the viscosity of the material to be dispensed, provision of specific venting means may not be required.

Typically the ventilation means, when provided, may comprise one or more ball valve arrangements which opens and closes in response to the rise and fall of the liquid. The embodiment shown in Figures 10a and 10b comprises individual ball valves 40,41 for regulating the filling and emptying of each chamber 27. The filling valve 40 communicates with the chamber 27 via a filling valve aperture 42 defined in the back 22 of the drum. Similarly the emptying valve 41 communicates with the chamber 27 via an emptying valve aperture also defined in the back 22 of the drum. During

operation these valves facilitate the release and influx of air as the chamber 27 is filling or emptying respectively, while also preventing any flow of liquid through the valves themselves.

Typically the housing, the reservoir unit and their internal components are all manufactured from a suitably resilient and chemically inert plastics material, for example high density polyethylene. The exact nature of the material is not important provided that it is not adversely affected by contact with the material to be dispensed. For ease of manufacture a material which facilitates fabrication by blow moulding or injection moulding techniques is preferable.

Preferably, a spring or other biasing means (not shown) are provided in order to fix the drum within the housing. For example, a male/female coupling may be provided wherein the drum defines a recess along and about the axis of rotation which receives a cooperating male part formed on the inside of the housing. Alternatively, the cylindrical drum wall may have one or more ridges running along its outer surface which cooperate with grooves defined in the inside surface of the cylindrical wall of the housing. Any such arrangement should fix the drum within the housing in a manner which facilitates the rotation of the former within the latter, while maintaining a liquid tight fit between the drum and the housing. Any biasing means may provide for two or more modes such as for example a resting or stationery mode, wherein the function of the biasing means is to apply sufficient force so as to minimise or eliminate any leakage, and an operational mode, wherein the force applied by the biasing means is reduced (compared to that applied in resting mode) in order to further facilitate displacement of the reservoir unit within the housing.

The volume of liquid dispensed with each rotation depends on the volume of the chambers 27.

Typically chamber volumes of about 1 mL to 25 mL would be useful for dispensing cleaning agents such as detergents, surfactants and liquid soaps. Dispensers having suitably larger or smaller chambers are envisaged for dispensing other materials. While the embodiments shown in the drawings depict two or three chamber drums, clearly the number of chambers may be varied as desired by changing the number of internal baffles present.

Preferably, means are provided reversibly stopping rotation of the drum within the housing so as to define a series of filling and emptying configurations. For example the external surface of the drum wall 21 and the internal surface of the cylindrical wall 11 may be fabricated with cooperating nodes (not shown) and recesses (not shown). The nodes and recesses thus provided reversibly engage

each other and are located so as to define the sequential filling and emptying positions of the drum chambers.

Indicator means may be provided on the front 23 of the drum 20, or elsewhere on the dispenser, which communicate to the operator when the dispenser is in a filling or emptying position.

Additionally a gauge or counter may be provided to indicate the total volume dispensed through the dispenser at a given point in time.

Preferably the drum is rotatably fixed within the housing in a manner which facilitates its removal therefrom for the purposes of cleaning and maintenance.

The embodiments described above are based on the rotation of a drum within a cylindrical housing.

A further embodiment of the invention, shown schematically in Figures 11 a and 11 b, is provided which comprises an oblong or tubular housing 50 in combination with a similarly shaped reservoir unit 60 which is mounted therein in a manner which facilitates translational displacement of the reservoir unit 60 within the housing 50. For example the reservoir unit may be displaced along the length of the housing in a reciprocal fashion. The housing 50 has at least one housing inlet 52 and at least one housing outlet 53. The housing inlet 52 is fixable to, and communicable with a bulk container via suitable means 51. Baffles 63 defining a plurality of chambers 64 are provided within the reservoir unit 60. Each of said chambers 64 defines at least one port facilitating communication with the housing inlet and the housing outlet in sequence. Each chamber may define two ports, a chamber inlet 61 and a chamber outlet 62, communicable with the housing inlet 52 and the housing outlet 53 respectively. Means are provided for displacing the reservoir unit 60 relative to the housing 50 in order to facilitate sequential alignment of the housing inlet 52 with the chamber inlet 61 of a first chamber 64 and subsequently a housing outlet 53 and the chamber outlet 62 of said first chamber 64.

Such displacement means may be motorised in which a suitable controlling means may be provided to facilitate automatic or pre-programmed operation.

The housing inlet and housing outlet and each chamber inlet and chamber outlet are positioned relative to each other such that upon translational displacement of the reservoir unit within the housing the chamber inlet of a first chamber may be aligned with the housing inlet while simultaneously the chamber outlet of a second chamber is aligned with the housing outlet. Thus as a first chamber is filling, a second chamber is simultaneously emptying. Furthermore, as with the embodiments

described above, the spacing of the chamber inlet and outlet ports and those of the housing are such that a chamber cannot have its inlet port aligned (wholly or partially) with the housing inlet at the same time as its outlet port is aligned with the housing outlet. Were such configuration possible material could flow through the dispenser in an unreguiated and uncontrolled manner, defeating a primary objective of the invention.