The invention relates to a cartridge for removable con ^¬ nection to a mixing device to form a device for dosing a

flowable substance into a liquid, the cartridge including:

a housing accommodating a reservoir for holding the flowable substance;

an outlet port for connection to an inlet port of the mixing device on connection of the cartridge to the mixing de ^¬ vice; and

a conduit of flexible material, arranged to form at least part of a conduit connecting the reservoir to the outlet port, wherein a least a section of the conduit of flexible mate ^¬ rial is arranged to form part of a peristaltic pump including at least one motor; and

at least one actuator element with a moveable contact surface, coupled to the at least one motor, at least in use, for causing the conduit section to be at least partly compressed at successive locations along its length,

wherein at least a part of the conduit of flexible ma ^¬ terial comprising the conduit section included in the

peristaltic pump is mounted to the cartridge, such as to enable a force counteracting a force caused to be exerted by the at least one actuator element on the conduit section included in the peristaltic pump to be exerted on the conduit section.

The invention also relates to a mixing device, includ- ing:

an interface for removably connecting a cartridge in ^¬ cluding a reservoir for holding a flowable substance to form a device for dosing the flowable substance into the liquid;

at least one motor, arranged to form part of a peri- staltic pump including a flexible conduit section and at least one actuator element with a moveable contact surface for causing the conduit section to be at least partly compressed at succes ^¬ sive locations along its length, at least one of the at least one actuator element being coupled to the motor, at least in use,

wherein at least a part of the flexible conduit com ^¬ prising the conduit section included in the peristaltic pump is mounted to the cartridge, such as to enable a force counteract ^¬ ing a force caused to be exerted by the at least one actuator element on the conduit section included in the peristaltic pump to be exerted on the conduit section.

The invention also relates to a system for dosing a flowable substance into a liquid.

FR 2 672 279 Al discloses an appliance for distributing a pasty or liquid product comprising an interchangeable part comprising at least a container of such a product and a pumping sub-assembly connected to the container; and an operating part, permanently installed, comprising at least an entrainment means adapted to be coupled to the pumping sub-assembly. In the il- lustrated example, the pumping sub-assembly is a peristaltic pump box. The peristaltic pump comprises an actuating mecha ^¬ nism, accessible in the centre thereof. The appliance is configured such that an axle of an electric motor comprised in the entrainment means can be introduced into the centre of the actuating mechanism.

A problem of the interchangeable part is that it is difficult to achieve both accurate dosing and easy mounting of the interchangeable part without adding to the complexity of the interchangeable part. Either the axle end and the centre of the actuating mechanism into which it is introduced are a tight fit, in which case it is not easy to insert the axle into the actuat ^¬ ing mechanism, or there is a fair amount of play, in which case it is difficult to dose the liquid or pasty product without the addition of gears in the interchangeable part.

It is an object of the invention to provide a car ^¬ tridge, device and system of the types mentioned above in the opening paragraphs for forming a system for relatively accurate dosing of a flowable substance into a liquid in which the car ^¬ tridge is relatively inexpensive and easy to handle by the user of the system.

This object is achieved with the cartridge according to the invention, which is characterised in that the at least one actuator element is journalled on the mixing device and in that the conduit section included in the peristaltic pump is arranged to be compressed by forces caused to be exerted by the at least one actuator element only when the cartridge is connected to the mixing device.

Thus, the expensive parts of the peristaltic pump are situated in the mixing device rather than in the cartridge. The cartridge is easy to handle, because the user need not remove the flexible conduit from the cartridge to mount it in the mix- ing device. It remains mounted in the cartridge in a manner to enable a force caused to be exerted by the movable actuator (s) on the flexible conduit to be counteracted by a force exerted by the remainder of the cartridge. The outlet port of the car ^¬ tridge can be permanently connected to the cartridge housing. For example, it can be connected to the cartridge housing via a linkage defining a limited range of movement. Alternatively, it can be fixed in position relative to the cartridge housing, e.g. by being provided in an outer wall of the cartridge housing. In this alternative, connecting the cartridge to the mixing device positions the outlet port relative to the inlet port of the mix ^¬ ing device. Because the actuator elements are journalled on the mixing device, they can and indeed do, remain coupled to the mo ^¬ tor (generally via a transmission mechanism that effects a tight coupling between each motor and the actuator element (s) coupled to it) . The motor can be a stepper motor of which the movement is accurately transmitted to the actuator element (s) with sub ^¬ stantially no play. Because the conduit section included in the peristaltic pump is arranged to be compressed by forces exerted by the moveable actuator elements only when connected to the mixing device, any mismatches between the cartridge and the drive system are absorbed by the compression of the flexible conduit. The degree of compression is less critical to the dos- ing accuracy of the peristaltic pump. The cartridge is

relatively inexpensive because the actuators are not included. This also makes it possible to use a cartridge with a smaller reservoir without substantially increasing the costs per unit of flowable substance, because the costs of the cartridge will es- sentially depend only on how much material is required to fabricate the reservoir and cartridge.

It is observed that EP 0 053 813 A2 discloses a dispos ^¬ able package for use in dispensing systems, wherein the package contains a liquid which is dispensed through a dispensing tube of the package, said dispensing tube having at least a section of flexible material which is for engagement by the rotor of a peristaltic pump for the dispensing of the liquid, the dispens ^¬ ing tube having shoulder or flange means for location in

relation to a mounting means associated with a peristaltic pump, so that the said section of the flexible tube will be mounted in a predetermined location in relation to the peristaltic rotor, when in use. To replace the disposable package, a user must break open a base of an outer case of the package, pull out the dispensing tube and position a section of the dispensing tube between collars around the peristaltic pump rotor. Thus, in the known cartridge, no part of the conduit of flexible material comprising the conduit section included in the peristaltic pump is mounted to the cartridge, such as to enable a force counter- acting a force exerted by the actuator (s) on the conduit section to be exerted on the conduit section included in the peristaltic pump .

In an embodiment of the cartridge, the cartridge hous- ing includes at least one wall section defining a region of the cartridge into which at least one of the actuator elements is at least partially insertable.

An effect is that the conduit of flexible material need not be provided at an exposed location on the outside of the cartridge. The region of the wall section into which at least one of the actuator elements is at least partially insertable can be closed by a component, e.g. a membrane or hinged flap, that is pushed in or pushed aside by the actuator elements as they are inserted.

In another embodiment, the cartridge housing includes at least one wall section defining a region of the cartridge within which an element for engaging at least one of the actua ^¬ tor elements is movably arranged so as to transfer a force from the at least one actuator element to the flexible conduit sec- tion included in the peristaltic pump.

An effect is again to enable the conduit of flexible material to be provided at a shielded location in the cartridge housing .

In an embodiment of the cartridge according to the in- vention, the peristaltic pump is a linear peristaltic pump.

An effect is that the actuator elements need carry out only internal movement and can be journalled at stationary posi ^¬ tions. This allows for miniaturisation at relatively low cost, since it is not necessary to guide the movement of actuator ele- ments with great precision.

In a variant of this embodiment, the cartridge includes an array of elements, each including at least a section arranged to execute reciprocating movement between a position in which the element causes the conduit section included in the peristal ^¬ tic pump to be at least partially occluded at a position along its length and a position to which it is returned by a force ex ^¬ erted by a resilient element.

An effect is to provide an array of elements acting as cam followers for actuator elements arranged on or in the mixing device. The resilient element can be the flexible conduit. In some variants, the elements of the array act directly on the conduit section included in the peristaltic pump, whereas in other variants, they act via an intermediate element. Rather than have the actuator elements of the peristaltic pump act di ^¬ rectly on the conduit section included in the peristaltic pump, the elements of the array of elements included in the cartridge are interposed between the actuator elements and the conduit section included in the peristaltic pump. The actuator elements of a linear peristaltic pump will generally be in the shape of rotating cams. The interposition of the array of elements al ^¬ lows the conduit of flexible material to be recessed more deeply in the cartridge, but it also ensures that only a transverse force is exerted on the conduit of flexible material. This avoids the wear that would arise if the cams were to act direct ^¬ ly on the conduit of flexible material.

In a variant, the elements in the array include at least one cantilever.

An effect is that the cantilevers can act as levers, e.g. third-class levers. In the latter case, the actuator ele ^¬ ments can have less excentricity, and they can be smaller in size. In particular where the mixing device and the cartridge are configured such that the actuator elements extend partially into the cartridge upon connection of the cartridge to the mix ^¬ ing device, there need be less space for the actuator elements to move within the cartridge in this variant. In an embodiment, the cartridge includes a support sur ^¬ face, and the conduit section included in the peristaltic pump is positioned against the support surface along at least part of its length.

An effect is that the force counteracting the force cause to be exerted by the actuator element (s) is provided to a large extent by the support surface, rather than through

stretching of the conduit of flexible material. Compared to a variant in which the conduit of flexible material is merely fixed at a few positions along its length, this variant avoids local stresses on the conduit of flexible material.

In an embodiment, the cartridge includes at least one locking element for cooperating with locking elements of the mixing device to exert a locking force in a first direction.

An effect of this embodiment is to allow the mixing de ^¬ vice to be simpler and more compact compared to a variant in which the cartridge is completely inserted into a chamber in the mixing device and retained by a lid that closes the chamber.

The or each locking element can comprise a locking surface for engagement by a latching element of the mixing device, for exam ^¬ ple .

In a variant, the support surface at least partially faces in the first direction along the length of the conduit section included in the peristaltic pump.

An effect is to enable the section of the flexible con ^¬ duit included in the peristaltic pump to be at least partially occluded at certain locations along its length by the very act of connecting the cartridge to the mixing device. The force of the support surface acts on the conduit section and thus at least indirectly on the actuator elements journalled on the mix ^¬ ing device, but cannot push the cartridge away from the mixing device, because it is retained by the locking mechanism compris ^¬ ing the locking elements of the cartridge and the mixing device. In a variant, the cartridge further includes at least one guidance element for co-operating with guidance elements of the mixing device to define a path of relative movement termi ^¬ nating in a final relative position in which the locking

elements of the cartridge are able to engage the locking ele ^¬ ments of the mixing device.

An effect of this embodiment is to make it easier to align the inlet port of the mixing device and the outlet port of the cartridge. The same could be achieved by allowing for some degree of play between the cartridge and the associated inter ^¬ face on the mixing device, but this might easily result in vibration or noise due to movement of the cartridge caused by the actuator elements. Moreover, a relatively high amount of play between the cartridge and the mixing device would result in less well-defined occlusion of the conduit section included in the peristaltic pump, and thus in less precise dosing of the flowable substance into the liquid. In this variant, accurate positioning by at least the locking elements is achievable with ^¬ out making connection of the cartridge to the mixing device a fiddly exercise.

In a variant of this embodiment, the guidance elements are arranged to cause the cartridge to change its orientation along the path, such that the path is directed in the first di ^¬ rection at at least the final relative position.

An effect is to allow the cartridge to be brought into contact with the mixing device in any one of a range of orienta ^¬ tions, whereupon the cartridge is guided towards the correct orientation for connecting the inlet port of the mixing device to the outlet port of the cartridge.

According to another aspect, the mixing device accord ^¬ ing to the invention is characterised in that the at least one actuator element is journalled on the mixing device. Because the actuator elements are journalled on the mixing device, they can and indeed do, remain coupled to the mo ^¬ tor (generally via a transmission mechanism that effects a tight coupling between each motor and the actuator element (s) coupled to it) . The motor can be a stepper motor of which the movement is accurately transmitted to the actuator element (s) with sub ^¬ stantially no play.

In an embodiment, at least one of the actuator elements is journalled to rotate about a fixed axis and is excentrically configured relative to the axis.

This embodiment is suitable for implementing a linear peristaltic pump. All actuator elements can be mounted to a single axle, driven by a single motor, which is relatively eco ^¬ nomical and avoids the need for synchronisation between the actuator elements. Rotary movement of the axle is translated into translational movement by means of the excentrically con ^¬ figured actuator elements. This arrangement is relatively compact compared to variants in which the actuator elements move along the conduit section included in the peristaltic pump. The actuator elements can be excentrically configured in the sense that they have a cross-sectional shape deviating from the circu ^¬ lar or in the sense that they rotate about a point removed from the centroid of the cross-section.

In an embodiment, the mixing device includes at least one locking element for co-operating with a locking surface of the cartridge to exert a locking force in a first direction.

The first direction corresponds to the direction in which the cartridge is moved relative to the mixing device to establish a connection between the two. The locking surface of the cartridge can be provided by a wall of the cartridge hous ^¬ ing, e.g. where the locking element of the mixing device

corresponds to a closure member of a chamber for accommodating the cartridge. In an alternative variant, the locking elements engage the locking surface (s) from a direction transverse to the first direction, so that the mixing device need provide only a shallow recess for receiving part of the cartridge, or no recess at all. In this variant, the mixing device can be more compact.

In a variant, the mixing device further includes at least one guidance element for co-operating with guidance ele ^¬ ments of the cartridge to define a path of relative movement of the cartridge terminating in a final relative position in which the locking elements of the mixing device engage the locking surfaces of the cartridge.

An effect of this variant is to make it easier to align the inlet port of the mixing device and the outlet port of the cartridge without having to increase the amount of play between the cartridge and the associated interface of the mixing device.

In a variant, the guidance elements are arranged to cause the cartridge to change its orientation along the path, such that the path is directed in the first direction at at least the final relative position.

This variant allows the cartridge to approach the mix- ing device at any of a range of orientations, making it easier still to connect the cartridge to the mixing device. For exam ^¬ ple, the guidance elements can define a pivot axis about which the cartridge can be swivelled into the final relative position. An implementation of such a set of guidance element would be at least one pair of a pivot pint and a recess for receiving the pivot pin, with the latter having orientation transverse to the direction of insertion into the recess.

An embodiment of the mixing device further includes at least one clamping element for co-operation with a surface of the cartridge and at least one abutment, spaced apart from and facing the clamping element on an opposite side of a space for accommodating at least an end part of the cartridge, wherein the clamping element is biased in a direction directed towards the at least one abutment.

An effect is essentially to fix the position of the cartridge in the direction from the clamping elements to the abutment, so that the risk of noise and vibration due to move ^¬ ment of the cartridge is reduced.

In a variant, at least one of the clamping elements corresponds to one of the locking elements.

Thus, the locking elements act as clamping elements and are constituted as latches that are biased into a latching posi ^¬ tion. They further act as clamping elements, so that they restrain movement of the cartridge in two mutually perpendicular directions .

A variant further includes an inlet port for connection to an outlet port of the cartridge on connection of the car ^¬ tridge to the mixing device to enable a transfer of the flowable substance to the mixing device, wherein the inlet port is pro ^¬ vided in the abutment.

An effect is to push the inlet port towards the outlet port, reducing the risk of leakage. Where at least one flexible sealing element is provided in or between the inlet port and the outlet port, these features suffice to establish an essentially fluid-tight connection between the inlet port and the outlet port. Further user involvement is not required.

An embodiment of the mixing device includes a recess for accommodating at least part of the cartridge and an inlet port for connection to an outlet port of the cartridge on con ^¬ nection of the cartridge to the mixing device to enable a transfer of the flowable substance to the mixing device, wherein the inlet port is located in the recess.

An effect is to shield the inlet port at least partial ^¬ ly. Moreover, the recess can play a role in orientating the outlet port of the cartridge relative to the inlet port of the mixing device when the cartridge is connected to the mixing de ^¬ vice .

In a variant of this embodiment, the recess has at least one essentially planar side wall.

This limits the number of orientations with which the cartridge can be inserted into the recess, so that the inlet port of the mixing device need not be located in the centre of the bottom wall of the recess. The cartridge can only be in ^¬ serted with one of a limited number of rotational positions relative to an axis of rotation parallel to the direction of in ^¬ sertion of the cartridge into the recess.

An embodiment of the mixing device further includes a control unit for varying a speed of the motor of the peristaltic pump, wherein the control unit is configured to adjust a speed of the motor in dependence on a flow rate of the liquid.

In a variant, the control unit is arranged to receive a signal representative of the flow rate of the liquid. In anoth ^¬ er variant, the control unit also controls or regulates the flow rate of the liquid, so that the flow rate need not be measured. An effect of this embodiment in its various variants is that consistent product quality can be achieved. The peristaltic pump allows for relatively accurate metering of the flowable substance. Dosing can be proportional to the flow rate, so that a constant ratio of flowable substance to liquid is achieved.

In an embodiment, the mixing device includes an inlet port for connection to an outlet port of the cartridge on con ^¬ nection of the cartridge to the mixing device to enable a transfer of the flowable substance to the mixing device, a mix ^¬ ing section for mixing the flowable substance with the liquid and a valve for closing off a fluid connection between the inlet port and the mixing section.

An effect is to close a fluid pathway from the mixing section to the environment of the mixing device, so that the liquid cannot escape when no cartridge is connected. This is especially useful when the mixing device is directly connected to a source of pressurised liquid, e.g. the water mains. The mixing section is a mixing chamber or a section of one of the conduit leading from the inlet port and a conduit carrying the liquid where it meets the other.

In a variant of this embodiment, the valve includes a valve member and a valve seat, the valve member being movable between a first position, in which it engages the valve seat to close off the fluid connection between the inlet port and the mixing section, and a second position, in which the fluid connection is freed, and the valve seat is provided in a wall at least partly delimiting the mixing section.

An effect is to enable the length of the fluid connec- tion between the mixing section and the inlet port to be

minimised. This can be significant where different cartridges with different flowable substances are available, because a long fluid connection would need to be cleaned, or the entire mixing system flushed before subsequent use after replacement of a car- tridge with one flowable substance by a cartridge with a

different flowable substance.

In an embodiment, the valve includes a valve housing and a valve member, movable within the valve housing between a first position, in which it closes off the fluid connection be- tween the inlet port and the mixing section, and a second position, in which the fluid connection is freed, and the valve includes a part configured to engage part of the cartridge when the cartridge is connected to the mixing device, such as to move the valve member from the first to the second position.

An effect is that the act of connecting the cartridge to the mixing device causes the valve to open. Compared to a one-way valve, the peristaltic pump need not create sufficient pressure to overcome the force closing the one-way valve. Thus, the motor of the peristaltic pump can be less powerful and the peristaltic pump is more responsive, allowing for more accurate metering of the flowable substance into the mixing section.

In an embodiment, the valve is comprised in a removable component of the mixing device, in particular a removable compo ^¬ nent that includes the inlet port.

An effect is to make it easier to clean the valve. The flowable substance cannot easily form incrustations. Further ^¬ more, different cartridges with different flowable substance can be used with the mixing device in a relatively user-friendly way. If the removable component includes the inlet port, this implies that the removable component is at a position that is externally accessible, because it must be possible to place the cartridge against it. Consequently, the removable component is easy to remove from the mixing device. It is therefore also relatively easy to clean the external surface against which the cartridge is placed. Furthermore, the conduit between the inlet port and the valve can be relatively short, allowing for more accurate dosing of the flowable substance. Further shortening is achieved if the removable component further includes the mix ^¬ ing section.

According to another aspect, the system according to the invention for dosing a flowable substance into a liquid com ^¬ prises at least one cartridge according to the invention and a mixing device according to the invention.

In an embodiment of the system, at least one of the cartridge and the mixing device includes at least one locking element for co-operating with a locking surface provided on the other of the cartridge and the mixing device to exert a locking force in a first direction.

In a variant of this embodiment, one of the cartridge and the mixing device further includes at least one guidance el ^¬ ement for co-operating with guidance elements of the other of the cartridge and the mixing device to define a path of relative movement of the cartridge terminating in a final relative posi ^¬ tion in which the locking elements engage the locking surfaces.

In a variant of this system, the guidance elements are arranged to cause the cartridge to change its orientation along the path, such that the path is directed in the first direction at at least the final relative position.

In an embodiment of the system, one of the cartridge and the mixing device further includes at least one clamping el- ement for co-operation with a surface of the other of the cartridge and the mixing device and at least one abutment, spaced apart from the clamping element, on an opposite side of a space in which, when the cartridge is connected to the mixing device, an end part of the cartridge is arranged, for abutting an abutment of the other of the cartridge and the mixing device, and the clamping element is biased to move the abutments towards each other.

In a variant of this embodiment, at least one of the clamping elements corresponds to one of the locking elements.

In a further variant, the mixing device further includes an inlet port for connection to the outlet port of the cartridge on connection of the cartridge to the mixing device to enable a transfer of the flowable substance to the mixing de ^¬ vice, and the inlet port is provided in the abutment of the mixing device.

The invention will be explained in further detail with reference to the accompanying drawings, in which:

Fig. 1 is a schematic diagram providing an overview of several components of a system for dosing a flowable substance into a liquid;

Fig. 2 is a side view of a first embodiment of a remov ^¬ able cartridge for such a system; Fig. 3 is a rear view of the removable cartridge of

Fig. 2;

Fig. 4 is a front view of the cartridge of Figs. 2 and

3;

Fig. 5 is a view of an interface for connecting the cartridge to a mixing device of the system;

Fig. 6 is a perspective view in cross-section of the removable cartridge of Figs. 2-4 when connected to the mixing device ;

Fig. 7 is a cross-sectional view from a first direction showing details of the cartridge and the mixing device at the interface between the two;

Fig. 8 is a cross-sectional view from a second direc ^¬ tion showing details of the cartridge and the mixing device at the interface between the two;

Fig. 9 is a side view of a second embodiment of a re ^¬ movable cartridge for a system for dosing a flowable substance into a liquid;

Fig. 10 is a rear view of the cartridge of Fig. 9;

Fig. 11 is a front view of the cartridge of Figs. 9 and

10;

Fig. 12 is a bottom view of the cartridge of Figs. 9-11;

Fig. 13 is a top plan view of a first embodiment of an interface of a mixing device for use in association with the cartridge of Figs. 9-12;

Fig. 14 is a top plan view of a second embodiment of an interface of a mixing device for use in association with the cartridge of Figs. 9-13;

Fig. 15 is a rear view of a third embodiment of a re ^¬ movable cartridge of a system for dosing a flowable substance into a liquid; Fig. 16 is a side view of the cartridge of Fig. 15 showing some internal components in dashed outline;

Fig. 17 is a cross-sectional view of an interface of a mixing device for use in association with the cartridge of

Figs. 15 and 16; and

Fig. 18 is a cross-sectional view of a removable compo ^¬ nent of any of the mixing devices of Figs. 7-9, 13, 14 and 17.

A system for dosing a flowable substance into a liquid includes a mixing device as shown in outline in Fig. 1. The mixing device includes a tank 1 for holding the liquid, a pump 2 for pressurising the liquid and a mixing chamber 3, where a flowable substance is mixed with the liquid to form a diluted solution and/or dispersion. The resulting liquid is dispensed from the mixing device.

In the following, water will be used as an example of a liquid into which a flowable substance is dosed.

In one embodiment, the liquid tank 1 is removable from the mixing device, so that it can be filled with water under a household tap. In another embodiment, the mixing device in- eludes a connector for connecting the mixing device to the mains water supply.

The liquid tank can include a device for treating the water, e.g. a device including a filter bed comprising at least one of an adsorbent, an absorbent, an ion exchange material, a catalyst, a desorbent and a chelating material. In one variant, this device is in the form of a removable cartridge, e.g. a suc ^¬ tion cartridge for connection to an interface provided at an outlet of the liquid tank 1. In the illustrated embodiment, the cartridge is a gravitational filter cartridge 4 for connection to an opening of a funnel 5 arranged in the liquid tank 1.

It is observed that, instead of a mixing chamber 3, a mixing section corresponding to the intersection between two conduits can be provided. The flowable substance can be a granular medium, a paste or a liquid, generally with a higher viscosity than the liquid into which it is dosed. In a particular embodiment, the flowable substance includes a concentrate for preparing a bever- age, in particular a concentrate comprising a flavouring. The flowable substance can alternatively or additionally comprise a food supplement, such as a mineral composition, or an acidity regulator. In conjunction with the filter cartridge 4, the flowable substance allows for the addition of selected minerals to the liquid that may have been removed by the filter bed. The flowable substance can be dosed into the liquid relatively accu ^¬ rately. If the filter cartridge 4 essentially removes certain minerals that are added with the flowable substance, e.g. magne ^¬ sium and/or calcium, the mineral content of the liquid can be controlled relatively accurately, regardless of the properties of the mains water.

In the same vein, the flowable substance can be used to regulate the acidity level of the liquid relatively accurately in embodiments in which the filter cartridge 4 causes a drop in the pH of the water. In a variant of such an embodiment, the mixing device further includes a device (not shown) situated downstream of the mixing section for admixing carbon dioxide. Accurate regulation of the acidity level allows for the produc ^¬ tion of carbonated beverages with a consistent quality.

The pump 2 is controlled by a control unit 6. In the illustrated embodiment, the control unit 6 further controls or regulates a motor 7 of a peristaltic pump for transferring the flowable substance from a removable cartridge (not shown in Fig. 1) to the mixing device. The motor 7 is a stepper motor in one embodiment, allowing for relatively accurate dosing of the flowable substance using open-loop control.

The use of a peristaltic pump allows the system to meet food hygiene standards in a relatively simple way. Moreover, relatively accurate dosing is possible, because the amount of flowable substance transferred depends essentially only on the number of intervals of rotation of the motor 7. Peristaltic pumps are also relatively inexpensive.

The systems described here are particularly inexpen ^¬ sive, because the expensive parts of the peristaltic pump are arranged in the mixing device rather than in the removable car ^¬ tridge .

Thus, for example, the mixing device includes a trans- mission arrangement 8 for translating rotation of an axle 9 of the motor 7 into movement of one or more actuator elements (not shown in Fig. 1) of an actuator device 10 that interacts mechanically with components of the peristaltic pump housed in the removable cartridge. In use, as will be explained in more de- tail, the actuator elements exert forces on components of the removable cartridge that are transferred directly or indirectly to a section of a flexible conduit so as to cause the latter to be at least partly compressed at successive locations along its length .

The flexible conduit is mounted to the cartridge, so as to enable a force counteracting a force caused to be exerted by the actuator element (s) on the section of the flexible conduit included in the peristaltic pump to be exerted on the flexible conduit section. In one embodiment, at least one of the flexi- ble conduit and the section thereof included in the peristaltic pump is fixed to the cartridge at at least two points along the length of the flexible conduit. A transversely directed force causes the flexible conduit to be compressed, i.e. narrow, by being displaced sideways and by stretching. In another embodi- ment, the transversely directed force causes the flexible conduit to be compressed because it is supported by a support surface on an opposite side. The relative configuration of the cartridge and actua ^¬ tor device 10 is such that the act of connecting the cartridge to the mixing device brings about a compression of the section of the flexible conduit included in the peristaltic pump as a result of engagement between the actuator elements and compo ^¬ nents of the cartridge. Because a locking mechanism is provided to lock the cartridge in place, this compression is maintained.

A first embodiment of a system comprising a mixing device 11 and a cartridge 12 is shown in Figs. 2-8.

The cartridge 12 includes a rigid outer cartridge hous ^¬ ing 13 accommodating a reservoir 14 (Fig. 7) for holding the flowable substance. In the illustrated embodiment, the reser ^¬ voir 14 comprises a flexible bag, arranged to collapse as it is emptied. This makes it unnecessary to vent the reservoir, mak- ing this embodiment relatively hygienic.

The cartridge 12 includes an outlet port 15 (Fig. 4) for connection to an inlet port 16 (Fig. 5) of the mixing device to which the cartridge 12 is to be connected. The connection between the inlet port 16 and the outlet port 15 is established by the act of connecting the cartridge 12 to the mixing device, as will be explained.

A flexible conduit 17 connects the reservoir to the outlet port 15 of the cartridge. The flexible conduit 17 can be made of silicone, PVC, polyurethane or neoprene.

In the illustrated embodiment, the peristaltic pump is a linear peristaltic pump. Accordingly, a section of the flexible conduit 17 is mounted, in the sense of being supported, in the cartridge 12 between an array of cantilevers 18 and a ridge 19 providing a support surface (Figs. 7,8) . The cantile- vers 18 are integrally formed with the cartridge housing 13.

They project from a side wall 20 (Fig. 8) to which they are at ^¬ tached at one end. The cantilevers 18 extend across openings defined in a bottom wall 21 of the cartridge housing 13 (Fig. 7) . In this way, the cantilevers 18 are accessible to ac ^¬ tuator elements 22 (Figs. 5-8) journalled on the mixing device to which the cartridge 12 is configured to be connected.

These actuator elements 22 are in the shape of cams mounted to an axle 23 connected to the transmission

arrangement 8 (Fig. 1) . In the illustrated embodiment, the ac ^¬ tuator elements 22 are both excentrically shaped and

excentrically mounted to the axle 23.

In use, the actuator elements 22 exert a force on the cantilevers 18 directed away from an outer surface 24 of the mixing device 11. These forces are transmitted as transverse forces to the section of the flexible conduit 17 that is com ^¬ prised in the peristaltic pump. They are countered by forces exerted by the support surface provided by the ridge 19 against which the flexible conduit 17 has been placed. A locking mecha ^¬ nism exerts a retaining force in an opposite direction, to ensure that the cartridge 12 is not pushed away from the mixing device 11.

In the illustrated embodiment, the locking mechanism includes two latches 25,26 arranged on the mixing device 11. In an embodiment, the latches 25,26 are spring-loaded or otherwise biased into a position of engagement. The latches 25,26 are ar ^¬ ranged to cooperate with a locking surface 27 in the form of a lower surface of a recess 28 formed in a rear wall 29 of the cartridge housing 13. The latches 25,26 are biased laterally into the rear wall recess 28. However, the cartridge housing 13 is not displaced, because a lower end is received in a recess 30 (Fig. 5) with an opening in the surface 24 of the mixing

device 11, such that a lower section of a front wall 31 of the cartridge housing 13 is pushed towards a side wall 32 of the re ^¬ cess 30 (Fig. 7) . It is noted that the outlet port 15 of the cartridge 12 and the inlet port 16 of the mixing device are pro ^¬ vided in this section of the front wall 31 of the cartridge housing 13 and this side wall 32 of the recess 30 respectively. As a consequence, the latches 25,26 tend to push the inlet port 16 and outlet port 15 towards each other.

Means are provided for guiding the cartridge 12 into a position in which it is locked to the mixing device 11. These means also allow an asymmetric arrangement of the locking mecha ^¬ nism (i.e. latches 25, 26 on only one side of the recess 30) . In the illustrated embodiment, the guidance means comprise at least one swivel connection between the cartridge 12 and the mixing device 11, enabling the cartridge 12 to be rotated into a posi ^¬ tion in which it is locked to the mixing device 11. During this rotating movement, the cartridge 12 changes orientation.

The swivel connection is provided by protruding pins 33 (only one is shown in Fig. 5) provided in the recess 30 of the mixing device 11 and slots 34,35 provided in the cartridge hous ^¬ ing 13, the slots 34,35 terminating in a rounded surface via which the cartridge 12 is supported by the pins 33 during move ^¬ ment of the cartridge 12 relative to the mixing device 11. In another embodiment, the slots are provided on the mixing

device 11 and the pins on the cartridge 12. The slots 34,35 can narrow towards the rounded support surface terminating the slots and or widen at the openings of the slots 34,35, so as to make it easier to establish a first connection between the

cartridge 12 and the mixing device 11.

A second embodiment of a system for dosing a flowable substance into a liquid is shown in two variants in Figs. 9-14. It again comprises a cartridge 36 having an essentially rigid housing 37 in which a reservoir 38 (Fig. 9) for holding the flowable substance is accommodated. The cartridge 36 includes a flexible conduit of which a section 39 (Fig. 12) is arranged in a loop within a recess 40 in a bottom wall 41 of the

cartridge 36. The flexible conduit connects the reservoir to an outlet port 42 of the cartridge 36. The conduit section 39 in the recess 40 is supported by a bottom wall 43 of the recess 40, and is part of a peristaltic pump of which the remaining parts are external to the cartridge 36.

The cartridge 36 is provided with locking elements and guidance elements, which are similar to those of the system il ^¬ lustrated in Figs. 2-8. Thus, the cartridge 36 is provided with a recess 44 in a rear wall 45 of its housing 37, of which a lower surface provides a locking surface 46. The cartridge 36 is also provided with guidance elements in the form of slots 47,48.

In a first variant of a mixing device 49 (Fig. 13), a recess 50 is provided in an outer surface 51 of the mixing de ^¬ vice 49, in which an actuator device 52 is rotatably arranged. The actuator device 52 is coupled to the transmission arrange ^¬ ment 8 (Fig. 1) . The actuator device 52 has a generally

truncated conical configuration, tapering towards a distal end (with respect to the recess 50) . Multiple actuator elements 53 (in this case four) in the form of bulges are integrally formed on the actuator device 52.

Locking elements in the form of latches 54,55 are pro- vided in a first side wall 56 of the recess 50 opposite a second side wall 57, in which an inlet port (not shown) of the mixing device 49 is provided. The latches are biased in the direction of the second side wall 57 and are arranged to co-operate with the locking surface 46 of the cartridge 36 to lock the car- tridge 36 in place when inserted into the recess 50.

Protruding pins 58,59 are arranged in the recess 50 to co-operate with the slots 47,48 provided in the cartridge 36 to provide a swivel connection between the cartridge 36 and the mixing device 49. Thus, the slots 47,48 and pins 58,59 guide the cartridge 36 into a locked position, with the cartridge 36 changing its orientation along the way.

The act of guiding the cartridge 36 into the locked po ^¬ sition causes the flexible conduit section 39 to be compressed at at least one location along its length, depending on the azi- muthal position of the actuator device 10. Due to the

essentially conical configuration of the actuator device 52, the flexible conduit section 39 is slightly stretched in radial di- rection. Subsequent rotation of the actuator device 52 causes the locations at which the flexible conduit section 39 is com ^¬ pressed to move along its length, resulting in a peristaltic pumping effect. It is noted that the user need not place the flexible conduit section 39 around the actuator device 52, but need merely insert the bottom end of the cartridge 36 into the recess 50 such that the cartridge 36 is locked in place.

A second variant (Fig. 14) comprises a mixing device 60 that functions in essentially the same way as the first variant, but is provided with an alternative actuator device in the form of multiple separate actuator elements 61 journalled at the ends of arms 62 extending from a hub 63 of the actuator device. The hub 63 is again coupled to the transmission arrangement 8

(Fig. 1), so that it can be driven by the motor 7. Each of the actuator elements 61 has a slightly conical shape for easy en- gagement with the conduit section 39, when the cartridge 36 is connected to the mixing device 60. Again, the act of locking the cartridge 36 to the mixing device 60 causes the flexible conduit section 39 to be compressed at at least one location along its length. Rotating the actuator device causes the con- duit section 39 to be compressed at successive locations along its length.

The locking and guidance mechanisms of the second vari ^¬ ant are the same as those of the first variant, so that the second variant also includes a pair of latches 64,65 provided in a first side wall 66 of a recess 67 for receiving a bottom end of the cartridge 36. It further includes pins 68,69 for co ^¬ operating with the slots 47,48 to guide the cartridge 36 into the locked position. A third embodiment of a system for dosing a flowable substance into a liquid is illustrated in Figs. 15-17. A car ^¬ tridge 70 includes a housing 71 in which a reservoir 72 for holding the flowable substance is arranged. It further includes an outlet port 73, connected to the reservoir 72 by a flexible conduit, of which a section 74 is part of a peristaltic pump. All other components of the peristaltic pump are mounted on or in a mixing device 75 (Fig. 17) to which the cartridge 70 is connectable .

A side wall 76 of the housing 71 extends along an upper section of the height of the housing 71. Together with a further side wall 77, the side wall 76 defines an opening 78 into which an actuator device 79 mounted on the mixing device 75 is partially insertable. The actuator device 79 includes multiple actuator elements 80 in the form of radially directed, integral protrusions of the generally disc-shaped actuator device 79.

When inserted into the space defined between the two side walls 76,77 of the cartridge housing 71, the actuator

elements 80 cause the flexible conduit section 74 to be com- pressed at at least one location long its length. When the actuator device 79 is then rotated, these locations are dis ^¬ placed along the length of the conduit section, causing the flowable substance to be pumped from the reservoir 72.

The flexible conduit section 74 is arranged in a loop, supported along at least part of its outer circumference by a support surface 81. The support surface 81 exerts a lateral force on the flexible conduit section 74 that counteracts the forces exerted by the actuator elements 80.

To ensure that the compression is maintained, the car- tridge 70 is locked to the mixing device 75. In this

embodiment, recesses 82,83 are provided in front and rear walls 84,85 of the cartridge housing 71 respectively. The re ^¬ cesses 82,83 provide locking surfaces 86,87. Latches 88,89 for co-operating with the rear locking surface 87 are shown in

Fig. 17. At least one latch (not shown) for co-operating with the front locking surface 86 is also provided on the mixing de ^¬ vice. The cartridge 70 is connected to the mixing device 75 by placing it with its side wall 76 against a wall 90 of the mixing device 75 and pushing it downwards until the latches 88,89 en ^¬ gage .

The flowable substance that is to be dosed into the liquid will generally be more viscous than the liquid. Being provided in collapsible reservoir 14,38,72 with no venting arrangement, it will not normally flow out of the

cartridge 12,36,70 when the peristaltic pump is not operated.

On the other hand, the liquid in the mixing device 11,49,60,75 may be at a slightly higher than atmospheric pressure. In addition, it may be desirable to operate the mix ^¬ ing device 11,49,60,75 as a dispenser of liquid without the additives introduced by mixing with the flowable substance. To prevent an escape of liquid via the mixing chamber 3, a valve is provided to close off a fluid connection between the mixing sec- tion and the inlet port 16.

An embodiment of a module 91 including a mixing cham ^¬ ber 92 is illustrated in Fig. 18. It can be used in any of the mixing devices 11,49,60,75 discussed above. The module 91 is configured to be removably inserted and retained in the mixing device 11,49,60,75, so that it can be cleaned relatively easily.

The mixing chamber 92 is defined by walls in which a liquid inlet 93, a liquid outlet 94 and a flowable substance in ^¬ let 95 are provided. A liquid inlet sealing ring 96 is provided to enable an end of a conduit for conducting liquid to the mix- ing chamber 92 to be at least partially inserted into the liquid inlet 93 to establish a fluid-tight connection. Similarly, a liquid outlet sealing ring 97 is provided to enable an end of a conduit for conducting liquid from the mixing chamber 92 to be at least partially inserted into the liquid outlet 94 to estab ^¬ lish a fluid-tight connection. The inserted conduits form a mechanism for retaining the module 91 in the mixing device 11, 49, 60, 75.

The walls of the mixing chamber 92 also define a valve seat for a valve member 98, which is arranged to move within the mixing chamber 92 and is biased into position closing the valve by a spring 99.

An outlet port 100 of one of the cartridges 12,36,70 comprises a protruding nipple 101, insertable into the flowable substance inlet 95, where a sealing ring 102 ensures a fluid- tight connection. An end surface 103 of the nipple 101 is con ^¬ figured to engage the valve member 98 when inserted into the flowable substance inlet 95. This causes the valve member 98 to be displaced out off the valve seat. A fluid connection between the reservoir 14,38,72 of the cartridge 12,36,70 and the mixing chamber 92 is established in this way. When the car ^¬ tridge 12,36,70 is removed, the nipple 101 is retracted and the valve member 98 returned to the position in which it closes off the flowable substance inlet 95. The arrangement of the valve seat in a wall of the mixing chamber makes the path along which the flowable substance has to travel to reach the mixing cham ^¬ ber 92 relatively short. This simplifies cleaning of the module 91. It also allows for more accurate dosing of the flow- able substance.

Because the control unit 6 (Fig. 1) controls both the pump 2 and the motor 7 that drives the peristaltic pump, it is able to add the flowable substance to the liquid at a rate pro ^¬ portional to the rate of flow of the liquid. This ensures a consistent product quality. Because the peristaltic pump is rel ^¬ atively accurate, the flowable substance can be relatively highly concentrated, because even small quantities of the flowa ^¬ ble substance can be dosed relatively accurately. The invention is not limited to the embodiments de ^¬ scribed above, which can be varied within the scope of the accompanying claims. For example, the flexible conduit can be connected to the reservoir by means of mating connectors or it can be welded to the reservoir. The reservoir and flexible con ^¬ duit can be made of different materials, or the reservoir can include additional lining material.

Any mechanical locking or clamping mechanisms can be used to secure the module 91 containing the mixing chamber 92 to one of the mixing devices 11,49,60,75.

LIST OF REFERENCE NUMERALS

1 - Liquid tank

2 - Pump

3 - Mixing chamber

4 - Filter cartridge

5 - Funnel

6 - Control unit

7 - Motor

8 - Transmission arrangement

9 - Motor axle

10 - Actuator device

11 - Mixing device

12 - Cartridge

13 - Cartridge housing

14 - Reservoir

15 - Outlet port

16 - Inlet port

17 - Flexible conduit

18 - Cantilevers

19 - Ridge

20 - Side wall

21 - Bottom wall

22 - Actuator elements

23 - Axle

24 - Outer surface of mixing device

25 - Latch

26 - Latch

27 - Locking surface

28 - Recess in rear wall of cartridge

29 - Rear wall of cartridge

30 - Recess

31 - Front wall

32 - Side wall of recess

33 - Pin

34 - Slot - Slot

- Cartridge

- Housing

- Reservoir

- Conduit section

- Recess in cartridge - Bottom wall

- Outlet port

- Bottom wall

- Rear wall of recess - Rear wall

- Locking surface

- Slot

- Slot

- Mixing device

- Recess

- Surface

- Actuator device

- Actuator elements

- Latch

- Latch

- First recess side wall - Second recess side wall - Pin

- Pin

- Mixing device

- Actuator elements - Arms

- Hub

- Latch

- Latch

- First side wall

- Recess

- Pin

- Pin

- Cartridge

- Cartridge housing Reservoir

Outlet port

Conduit section

Mixing device

Side wall

Further side wall

Opening

Actuator device

Actuator elements

Support surface

Front recess

Rear recess

Front wall

Rear wall

Front locking surface

Rear locking surface

Latch

Latch

Wall of mixing device Module

Mixing chamber

Liquid inlet

Liquid outlet

Flowable substance inlet

Liquid inlet sealing ring

Liquid outlet sealing ring

Valve member

Spring

Outlet port

Nipple

Sealing ring

End surface