This invention has to do with dispensers for flowable materials, particularly viscous liquids such as gels and creams as typically used in pharmaceuticals, personal care and food products, and pasty materials such as toothpaste.
Pastes and gels have conventionally been dispensed from hand-squeezed plastic tubes with rigid plastic nozzles. More recently, larger paste dispensers have had a dispensing pump at the top of a free-standing upright container, usually a cylindrical container with a base in the form of a follower piston which rises up inside the container as the product is depleted so as to keep the system airless. A recent alternative for airless systems is to have paste in a collapsible bag inside an outer container.
The known pump-type dispensers for pastes are undesirably expensive, having numerous components.
One aspect of the present proposals is a dispenser for dispensing a flowable material from a container. It includes a tube defining a discharge flow channel between an inlet end and an outlet end. The tube has a resiliently deformable wall, and the dispenser provides for lateral deformation of the deformable wall across the discharge channel to compress the discharge channel laterally and thereby expel material from the outlet end. The dispenser may include an actuator element mounted beside the tube and movable laterally relative to it, e.g. by means of a sliding or pivoted mounting, to engage its deformable wall and compress it sideways.
The deformable wall, and preferably the entire tube wall (circumferentially) may be of resiliently deformable material e.g. elastomer. The thickness and material of the deformable tube wall may be selected, taking account of the viscosity of the material to be dispensed and the flow characteristics upstream, to give sufficient resilience for the restoration of the deformable wall to its rest condition to refill the discharge channel through its inlet portion after each dispensing. It may be a tube of cylindrical cross-section or of other e.g. oblong cross-section; an oblong cross-section enables a higher dose volume for a given operating stroke (along the minor axis).
For efficient operation it is of course preferable that the resistance to forward flow through the outlet be less than the resistance to flow back through the inlet. For this purpose an inlet valve function is preferably provided. This may use a conventional valve element, e.g. a flow-actuated flap or ball. Such a valve can close in known manner in response to an increase of pressure in the discharge channel. However we prefer to provide the valve function by arranging for a deformable wall portion of the discharge tube, to the upstream of the deformable wall referred to previously, to be displaced (e.g. by the same action that compresses the tube) to wholly or partially block the tube upstream of the compressed region so inhibiting or preventing flow back through the inlet as the tube is compressed.
A preferred way to do this is by arranging for a blocking portion, e.g. a longitudinally-localised lateral projection, of an actuator element as proposed above to move the deformable tube wall at the relatively upstream position in an initial stage of the actuating stroke so as wholly or partially to block off backflow, the remainder of the actuation stroke progressively compressing the tube downstream of the blockage to expel material through the outlet.
Irrespective of whether a block is created towards the inlet side, it is generally preferred that the action of the actuating element(s) is such that at a given stage of the actuating stroke, (preferably for more than half of its extent) the degree of compression of the tube progressively decreases along it in the downstream direction, favouring forward flow.
This proposal of using deformation of a discharge conduit wall to block an inlet (upstream) portion of a deformable pump chamber or passage at the onset of a pumping stroke, to provide an inlet valve function, is an independent invention proposed herein i.e. proposed irrespective of the particular shape and mode of compression of the discharge channel or pump chamber.
To keep the system airless and for effective priming, a discharge valve function at the outlet end is desirable. Again, for simplicity we prefer this to be achieved by the resilient deformability of the discharge tube wall. Thus, a discharge opening in the form of a slit through the discharge tube wall, and most preferably a forwardly-directed slit on a nozzle tip e.g. a duckbill formation, is convenient and effective.
This slit valve preferably constitutes the final discharge opening of the dispenser.
Drawing these themes together, a preferred version of our proposals is a dispenser, e.g. a dispenser for paste material such as gels and creams as typically used in pharmaceuticals, personal care and food products, having a discharge channel consisting essentially of a resilient elastomeric tube with an inlet end connected to receive material from a product container, preferably directly i.e. not via any directional inlet valve. It has an outlet end terminating in a tip with a slit-form opening e.g. a duckbill valve. An actuating element is mounted in the dispenser next to the elastomeric tube to be movable in a dispensing stroke laterally relative to the tube, compressing the tube. The actuating element includes a blocking portion towards the inlet end of the tube which moves laterally in advance of other parts of the actuating element to block the tube wholly or partly by squeezing it. The actuating element has a compression region extending downstream relative to the blocking portion, and preferably elongate in the flow direction, shaped and mounted so as to be brought in to press along the side of the tube and squeeze material from the outlet opening.
Preferably such an actuating element is mounted pivotally in the dispenser, e.g. extending downstream along the discharge tube relative to the pivot point. This can encourage an action tending to squeeze material outwardly. Additionally or alternatively, an engagement face of the actuating element may be inclined away from the tube so that compression is initially greater nearer the inlet than nearer the outlet.
The blocking portion of the actuating element may be formed separately from the compression portion that squeezes the product from the tube. Indeed, they may be on elements which are separate but move together. A simple and therefore preferred construction provides the upstream blocking portion and the downstream compression portion on the same component in one piece. This may be a component pivoted towards the inlet end of the discharge channel. Preferably the blocking portion is resiliently retractable relative to the compression portion, so that as the actuating element is pivoted further to deform the tube progressively, the blocking portion does not dig too forcibly into the tube wall and perhaps damage it, and/or hinder further movement of the actuating element.
The dispenser may use one actuating element, preferably with a static reaction abutment supporting the discharge channel from the opposite side, or may use opposed movable actuating elements to squeeze the tube dynamically from opposite sides.
The actuating element(s) may be exposed for direct manual engagement, or may be connected via operating mechanism, e.g. a lever or slider mechanism, to discrete manually-engaged element(s).
The product container (a pack consisting of a dispenser mounted on top of a filled or unfilled container is an aspect of the invention) is preferably of the airless or volume-adjusting kind having a collapsible bag or follower piston. However, other kinds of container may be used. The dispenser may be used either upright or inverted.
An advantage of having a slit or duckbill valve at the outlet is the ability to make a clean cut-off of dispensed products. A duckbill valve has a relatively acute convexity at its tip, leaving little forwardly-directed area for the adherence of dried residues.
Another benefit achievable with this system is that the product need not contact relatively movable discrete parts or metal parts, reducing the likelihood of contamination. Avoiding metal components may also enable recycling.
A further benefit with dispensing through a simple squeezed tube is that, with paste, we find that stripes applied to the paste survive dispensing in good shape, by contrast with piston-cylinder pump dispensers which spoil striping if conventional valves are used. Note that if a one-way follower piston is used in the container (e.g. having a pawl that engages the container wall to prevent reverse movement), inlet valve function at the dispenser inlet can be omitted altogether.
The dispenser may be provided with a closure component for a container, e.g. a snap- or screw-fit cap, at its inlet end. This may be attached to any suitable container. Indeed, it could be attached to a conventional toothpaste tube in place of its normal screw cap.
The deformable tube may be formed integrally in one piece with a cap or cover to extend over the top of a product container, and optionally including (in one piece) a sealing periphery adapted for sealing engagement around the top of a container, e.g. a cylindrical plastic container.
Embodiments of the invention are now described by way of example with reference to the accompanying drawings in which
FIGS. 5(a) to (d) show an actuating button in top, oblique, side and front views respectively;
FIGS. 6(a) and (b) are front and side views of an elastomeric discharge tube unit as seen
FIGS. 7(a) and (b) are front and side views of an alternative embodiment of elastomeric discharge unit;
Referring to
A pumping arrangement is secured at the top of the container 1, consisting essentially of an elastomeric discharge tube unit 3 secured over the opening of the container 1, and a housing body 2 which locates and supports the tube unit 3 in relation to the container shell 1′ and a movable actuating button 5 mounted beside the tube unit 3.
The tube unit 3 is shown in isolation in
The base of the cylindrical tube 32 flares out as an integral annular cap 34 having a peripheral upwardly-opening U-channel 35. In the assembled pack (see
This forms a sealed, open communication between the container interior 8 and the cylindrical discharge channel 31 in the elastomeric tube 32, closed at the top end by the slit valve 33.
The body 2 provides a shroud or casing with an eccentric top opening 23 through which the convergent tip of the elastomer tube projects. The body 2 also provides an inclined interior abutment 26 against which one side of the tube 32 rests. Opposite that abutment the housing or body 2 has a side opening 24 which exposes the actuating surface 51 of the actuating element 5. Looking at
The operating (front) surface of the element 5 features two downwardly-dependent limbs 54,57 one behind the other. The front limb 54 presents a generally flat engagement surface 55. The rear limb 57 projects to below the bottom edge of the front limb 54 and carries a forwardly-projecting flange 53. The limbs 54,57 are resiliently flexible relative to one another and to the actuating surface 51. In the rest condition (
As the actuator 5 is pushed forwardly, towards the position of
When the button is released, the resilient re-expansion of the tube wall 32 pushes the button back to its start position and generates a negative pressure which draws paste material up into the nozzle space 31 from the container space 8, the bag 1 collapsing slightly to compensate and venting air entering the intermediate space between bag 1 and shell 1′ through vent hole 11.
This dispensing action has a number of advantages, in particular the avoidance of any discrete springs or metal parts in the product path, the absence of discrete valve components, but nevertheless a positive pumping action from the valve effect of the flange 53.
Note also from
The one-piece movable actuator element 5 of the previous embodiments, with two downwardly dependent limbs 54, 57, is replaced with a laterally movable button 80 and leaf spring 81. The leaf spring 81 has a forwardly projecting flange 83, for indenting the lower part of the deformable tube wall 332, acting as a blocking portion. Situated above this flange 83 is a flat vertical portion 85, for compressing the tube and expelling flowable product through the duckbill valve 333. A horizontal top portion 84 of the leaf spring 81 is slottedly located between two closely spaced projections 801 of the inner wall of the actuating button 80.
The remaining parts of the tube 3, including the flare 534 at the base of the tube 3, are of rigid material Y. Using a two-shot moulding process to produce a tube of this kind is substantially cheaper than producing an entirely elastomeric tube, as elastomeric injection form materials tend to be rather expensive.
A blocking portion 93,93′ is provided at the bottom of the actuator element for indenting the inlet end of the deformable wall 532 of the tube 3, thus acting as an inlet valve.
The actuator elements of
The actuator element shown in
Number | Date | Country | Kind |
---|---|---|---|
0206176.0 | Mar 2002 | GB | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/GB03/01086 | 3/14/2003 | WO |