WO2005049477A2

WO2005049477A2 - Liquid dosing devices

Info

Publication number: WO2005049477A2
Application number: PCT/GB2004/004856
Authority: WO
Inventors: Brian Robert Law; Jeffrey William Spencer; Nicola Louise Morgan; Paul Harrison
Original assignee: Rieke Corporation
Priority date: 2003-11-18
Filing date: 2004-11-18
Publication date: 2005-06-02
Also published as: WO2005049477A3; GB0326849D0; AR047770A1

Abstract

The application describes liquid dosing devices of the kind in which flow to a front discharge opening (44) of a container is blocked after a controlled delay by a sliding piston (3) movable in a control chamber (2) mounted in a container neck behind the discharge opening (44). Movement of the piston (3) is governed by restricted flow through control openings (28) at the back of the control chamber (2). Restoration of the piston (3) after a dosing operation is assisted by providing a dump valve at the rear of the control chamber. For simplicity and ease of construction, as well as effective sealing operation, the dump valve member is a ball (6) retained in a cage (5). Another proposal provides a one-way valve in the outlet path, obviating the dump valve and enabling rapid recovery after a dosing operation when used with a resiliently squeezable container.

Description

LIQUID DOSING DEVICES

FIELD OF THE INVENTION This invention has to do with devices adapted for dispensing metered doses of liquid from a container, and containers incorporating such devices . In preferred embodiments the devices are used in, or adapted for use in, squeezable containers. A preferred field of use is that of containers for domestic or household use, containing detergents or other cleaning preparations, fabric conditioners, foods such as sauces and the like. Particularly, the invention is concerned with liquid dosing devices of a kind having an outlet passage leading to a front discharge opening, past or around a control chamber positioned behind the front discharge opening and having one or more rear control openings to admit a restricted flow of liquid from the container interior into the control chamber. An obturator such as a sliding piston is in the control chamber and adapted to advance, during dispensing, under the influence of liquid flowing into the control chamber behind it through the control opening (s). When the obturator has advanced sufficiently it blocks the outlet passage to terminate the dose. Usually the outlet path of the liquid leads from the container interior forwardly past outside the control chamber and then radially inwardly, around or through the front of the chamber wall, in front of the obturator to the discharge opening which is typically axial or central at the front of the device. The front of the chamber wall may then have one or more circumferentially- distributed flow openings as part of the outlet passage. BACKGROUND Dosing dispensers as described above, referred to below as being "of the kind described", are known. See for example our own EP-A-0274256 which describes a dispenser with a discharge opening having a rearwardly- projecting tubular extension from the front cap which provides at the same time a seat for the obturator to rest against and thereby block the outlet passage, and also a means for guiding the outgoing flow partly back towards the obturator to control its advance. Various other forms of dosing dispenser exist. Some of these have a metering chamber such as a cup or enclosed cylinder in the container neck. Liquid is brought into the chamber by inversion of the container, or by squeezing it up through a stem or valved conduit, whereupon it is separated from the body of product in the container and can be dispensed. See US 2331659. Devices of the kind described have an advantage, compared with such dispensers using a metering chamber adjacent the container mouth, that the volume dispensed is not swept out or held in the dosing device itself. It is therefore not necessary to provide a bulky device, or to wait, to obtain a substantial dose. In general there is an issue with speed and convenience; dispensers may be slow to restore, and usually need to be returned to an upright position to create a new dose or restart the mechanism. THE INVENTION In this application we make new proposals useful in dosing dispensers of the kind described. A first independent aspect of our proposals herein - although it may be combined with any other proposal herein - relates to a dump valve arrangement provided at the back of the control chamber to allow rapid escape of liquid from the control chamber behind the obturator after a dose has been dispensed, to speed return of the obturator to its rearward (starting) position. The dump valve is operable to close during dispensing - under gravity and/or forward fluid pressure - so that liquid enters the control chamber only through the control opening (s) . The dump valve opens after dispensing - under gravity and/or reverse fluid pressure - so that liquid can escape more rapidly than if the only escape route were through the control opening (s). The dump valve arrangement typically involves a dump opening at or through the rear of the control chamber. Preferably it is larger (in area) than the total control opening (s). A dump valve member is mounted movably between an open position in which liquid can flow out through the dump opening and a closed position in which the dump valve member blocks the dump opening. Constructions having this feature were described previously in our EP-A-0274256, where part of the rear chamber wall was movable to provide a valve action. However we have some new and useful proposals for such constructions, useful independently or in combination with one another or with other proposals herein. A first proposal in this aspect is to have the dump opening central, with one or more control openings peripheral to it . A second proposal is that the dump valve member and a dump valve seat of the dump opening are shaped so as to make a convergent guiding engagement; one or both of them may have an inwardly and forwardly convergent seating surface. This improves the speed and effectiveness of the seal made. The dump valve member is preferably discrete from the control chamber. Desirably the dump valve member has a convex curved surface to make said engagement. The most preferred dump valve member is a ball, for simplicity of manufacture and assembly. The dump valve member such as a ball may be retained in a cage at the back of the control chamber. Preferably this cage is a discrete component to facilitate assembly e.g. it may push, snap, lock or otherwise fit into or onto a rear end formation of the control chamber wall. A ball dump valve member has been found particularly easy to make and assemble as well as being positive and effective in action compared with the constructions described previously in our EP-A-0274256. The control opening (s) of the control chamber is/are preferably separate from the dump opening. This is not essential, however: for example a circumferentially- localised control opening may be recessed at the periphery of the dump opening (so that it will not be blocked by the dump valve member) , or a control opening may even be through the dump valve member itself. A second and independent aspect of our proposals is to provide a unidirectional valve inhibiting reverse flow in the outlet passage. On recovery after dispensing liquid is then prevented or restricted from returning to the container interior by way of the outlet passage, and instead selectively flows back into the container from the control chamber space behind the obturator, especially through the control opening (s). This speeds the return of the obturator to its rearward or retracted position so that another dose can be dispensed. When, as is preferred, the device is implemented in a resiliently squeezable container, this action may clear the control chamber and re-initiate the obturator even while the container is inverted (the front of the dosing device facing down) , with the important advantage that repeated doses can be dispensed without needing to right the container between doses. This retraction of the obturator also naturally draws liquid back out of the discharge nozzle, preventing or reducing dripping in between doses and (for the last dose of a set) reducing or avoiding the tendency for residual product to dry and block the outlet construction. The extent of these effects depends on the viscosity of the liquid, in a way which a skilled person readily appreciates, but in any event there is a speeding of retraction of the obturator and readiness for the next dose. The nature and disposition of the outlet valve for the outlet passage can be selected in accordance with the path followed by that passage. It should be before (upstream of) the position of blocking by the obturator. It may be a flap valve having an anchor part secured in the device adjacent the outlet path, or a free valve member moveable separately in a valve space. If the outlet path has more than one opening, they may be separately valved, or a single valve element may govern plural openings . In a preferred version (as mentioned above) the outlet path begins with substantially the entire space surrounding the control chamber - e.g. through a clearance between this chamber and a wider container neck in which it is mounted, preferably coaxially - and leads through or around the front edge of the control chamber, via one or more circumferentially-distributed openings providing a suitable flow cross-section, and inwardly to a central discharge outlet. Unidirectional valving may conveniently be provided adjacent to the front edge of the control chamber, acting from or against connecting structure which connects the control chamber to the adjacent neck or cap part of the device or container and provides one or more said flow openings, or against the cap or a discharge tube. This connecting structure may be integral with the control chamber, with the adjacent cap or neck part, or both, or it may be a separate element. In one embodiment the connecting structure includes a substantially radial flange to/from the control chamber wall, with one or more flow openings through the flange and an axially-movable free or flap valve element acting against the flange as its valve seat. This may be an annular valve element. The valve element may be fixed or trapped in place during the assembly of the control chamber into or onto a front cap or plate part of the device via the connecting structure. In general, in preferred constructions the control chamber and its connection structure are a single moulded unit, connecting to a front cap component of the device which also includes or mounts a discharge outlet and means for securing it onto/into a container neck opening, with the control chamber projecting back inside the container neck with a lateral or radial clearance for the outflow of product past it. The device preferably has an outer cover cap. The cover cap may include a plug closure for^' the discharge opening. The cover cap may be integrally hinged to a front cap as described. The form of the obturator is not particularly limited. It may be a swinging element or a linearly- moving piston. It need not make a sealing fit in the control chamber, provided that it will substantially occupy the area therein so as to reliably be moved forward by flow of liquid into the control chamber behind it. Its usual components are a blocking portion, for engaging with the outlet passage to block it, and guide means for guiding its movement in the control chamber. The guide means may comprise axially-elongate elements distributed around a periphery of the obturator, e.g. fins or lugs. The blocking portion may be a simple web, e.g. if the outlet passage provides a suitable rearwardly projecting seat or seal periphery for it to abut against. Additionally or alternatively the blocking portion may include a forward fitting projection to engage in the outlet passage or its discharge opening, but this is less preferred because of the greater tendency for sticking. In general, the components herein may be moulded plastics components, joining by snap or press engagements without requiring discrete fasteners. The device is therefore suitable for implementation in mass-produced containers e.g. for household products or food products. Embodiments of our proposals are now described by way of example, with reference to the accompanying drawings in which Fig. 1 is a side elevation of a first dosing device; Fig. 2 is an enlarged section at A-A of the Fig. 1 dosing device; Figs. 3 and 4 are respectively a perspective view and a sectional view of a ball-retaining cage of the device; Figs . 5 and 6 are oblique front and rear views of a control chamber component of the device; Fig. 7 is a perspective view of its obturator; Fig. 8 is a section, corresponding to Fig. 2, of a second embodiment having a screw cap; Figs. 9 and 10 are axial cross-sectional views of a second form of device including a flow valve, illustrating flows in the dispensing and recovery states respectively, and Figs. 11 and 12 are views corresponding to Figs. 9 and 10 and showing a further flow valve embodiment. With reference to Figs. 1 and 2, a dosing dispenser device 1 is designed to fit on the open neck of a plastic container 10, indicated in broken lines in Fig. 2. The dosing device has a front cap component 4, being a one- piece moulding providing a front plate 42, a central outlet tube 44 with a forwardly projecting nozzle 441, an outer securing skirt 41 having a first inner snap bead 411 by which it fixes onto the container neck 10, and a cover cap 45. The cover cap joins to the rest of the cap component 4 through an integral butterfly hinge 46 so that the cap 45 is position-bistable i.e. it prefers to be either fully shut or fully open (in the Fig. 2 position) without swinging freely in between. The underside of the cap 45 has an integral nozzle plug 451 which plugs the nozzle 441 when the lid is shut. The second major component of the device is a control chamber or insert cylinder component 2, seen separated from the other components in Figs. 5 and 6. This consists essentially of a closed cylindrical sidewall 25 defining internally a control chamber 29, and having around its front edge a connection structure in the form of an integral forward extension 21, meeting the cylinder sidewall 25 via a radial shoulder 24 and having a front fixing lip 22 which snaps in behind a second snap bead 412 of the cap skirt 41 (Fig. 2) . Three equidistantly-spaced flow openings 23 are provided through the forward extension 21, adjacent to the shoulder 24, and occupy about 50% of the circumference . Behind the front plate 42 of the cap 4 the central cylindrical outlet tube 44 projects back into the open front end of the control chamber 2. Further out, a plug seal skirt 43, also projecting integrally from the back surface of the cap 4, fits sealingly inside the forward extension 21 of the control chamber component 2. The described cap and insert are preferably of polypropylene, but other materials are possible. An obturator or control piston 3 (seen also in Fig. 7) is enclosed in the control chamber 29, and has a flat central disc 31 with a set of axially-projecting integrally-formed peripheral guide lugs 32 around its edge. The control piston 3 fits substantially - i.e. occupying nearly all the cross-section without being a tight fit - into the control chamber 29 so as to be freely slidable in it, between a forward position in which its central web surface 31 lies against and blocks the rear entrance to the outlet tube 44, and a rear position in which it lies against the rear wall 26 of the chamber 2. The piston 3 shown is of polyethylene, but other materials may be used. An outlet passage for liquid in the container therefore exists, as indicated by the arrow B, from the container's interior space 11 forward through the radial clearance between the chamber 2 and container neck 10, forward and in through the flow openings 23 to the space between cap 4 and chamber 2 (and in front of the control piston 3), in and forward through the rearward extension tube 44 of the outlet and out through the discharge nozzle 441. The rear wall 26 of the chamber 2 features a central dump opening 27 surrounded by a convergent valve seat

263, defined through a re-entrant wall portion 261 with a central securing collar 262. Small discrete control openings 28, in this case three openings spaced equidistantly, penetrate the rear wall adjacent the edge of the re-entrant portion 261. See Fig. 6. A retaining cage 5 - see also Figs. 3 and 4 - is snap-fitted onto the centre of the rear wall 26 by means of a base ring 51 of the cage snapping onto the rearwardly-projecting central collar 262 of the wall, which has a suitable snap groove. In this cage - which is a one-piece moulded plastics component having three side bars 53, three corresponding side window openings 52 and a back plate 54 - a plastic ball 6 is retained. The ball may be polypropylene. The dimensions of the ball 6 and cage 5 are such that the ball 6 cannot escape from the cage but when it lies against the cage back plate 54, as in Fig. 2, there is a substantial clearance for flow out of the control chamber 29 through the dump opening

27, around the ball and away through the cage windows 52 into the container interior 11. When the ball 6 lies in a forward position however its guided engagement in the convergent seat 263 completely seals the dump opening 27 and the only communication between the container interior 11 and the control chamber 29 is through the small control openings 28. Normally the container stands upright with the device 1 facing upwardly. To dispense a dose the container is upturned and squeezed (if squeezable as is preferred) . Liquid flows out to the discharge nozzle along the outlet path (arrow B) . At the same time the ball 6 moves forward, urged by gravity and the forward movement of liquid in the container. It's convergent form in relation to the seat guides it into place so that it effectively blocks the dump opening. Liquid nevertheless flows from the container interior into the control chamber 29 behind the control piston 3 through the control openings 28. At the beginning of the operation the control piston 3 is at the back of the chamber 2, and the initial rush of liquid along the outlet path B fills up the front part of the device (in front of the piston 3) tending to delay it, in particular preventing it from simply falling under gravity. However as liquid gradually enters the control chamber 29 under squeeze pressure through the restricted openings 28 the piston 3 moves forward, at a predetermined rate depending on the size of the openings 28, the viscosity of the liquid and the size of the outlet tube. Eventually its central web 31 meets the rear circular edge 443 of the outlet tube 44 and blocks the outlet passage, immediately stopping the flow and terminating the dose. The container may then be turned upright and, if squeezed, the squeeze is released. Under gravity and the weight of liquid in the control chamber, optionally also suction if a squeeze was released, the dump valve ball 6 falls open and liquid flows rapidly out from the control chamber 29 back into the container. At the same time there is a back flow of liquid from the front of the device back through the flow openings 23 into the container. Where a squeezed container has been released, the resulting suction assists in clearing liquid product from the front parts of the device. Where the squeezed container exerts a sufficiently powerful suction, it may be possible to open the dump valve and restore the control piston 3 to its rear position without having to bring the container upright; suck-back of product from the nozzle area may be achieved at the same time. If such powerful suction is available a further dose may be dispensed without having to bring the container upright, simply by squeezing the container again to shut the dump valve and re-initiate the control function. It will be appreciated that in any event the size of dose dispensed can be adjusted by adjustment of the flow areas available through the control openings 28 and the outlet flow openings 23, as well as the outlet tube 44. Fig. 8 shows a variant of the Fig. 2 construction in which the front cap 104 has a more axially compact securing skirt 141 with an internal screw thread 1412 rather than a snap bead. The integral forward extension 121 of the insert cylinder 102 pushes right onto the plug seal skirt 143 of the front cap, with its front lip 122 resting at the base of a channel 148 formed around this skirt 143. An annular sealing liner 149 fits into this channel behind the lip 122. When installed on the threaded neck of an appropriate container, the threaded engagement drives the edge of the container neck into contact with the ring 149, compressing the components together and sealing the construction. In this more axially compact device, the flow openings 123 are roughly in axial register with the rear entrance to the outlet tube 144. Figs. 9 and 10 show a different version of dosing device, particularly intended for low-viscosity products and designed to enable repeated dosing without having to right the container between doses. The general disposition of components (cap component 204, control chamber component 202, flow openings 223, control openings 228) is similar to the device of Figs. 1 to 7. However the radial shoulder 224 of the chamber component 202, through which it is secured into the cap 14, has a greater radial extent and has an axially-directed sealing surface 2241 at its front side. A free sealing ring 7 opposes this sealing surface, so that when pressed against it it closes the flow openings 223. The sealing ring 7 is trapped in position between the forward extension 221 of the component 202 surrounding it, the sealing surface 2241 behind it and the edge of the cap's plug seal skirt 243 in front of it. During dispensing (Fig. 9) fluid flows out through the flow openings 223 as described previously, the valve ring 7 being held open by gravity and flow pressure: arrow A. Control flow (arrow B) enters the control chamber leading to downward movement (arrow C) of the control piston 203 and eventual termination of the dose in the manner described previously. The container - a resilient squeeze container - is then released causing a drop of internal pressure. There are two routes for back flow; back through the control openings 228 (arrow Y in Fig. 10) with the effect of retracting the control piston (arrow Z), or back through the flow openings 223 (arrow X) . However initial flow X immediately closes the valve ring 7 against its seat, closing the flow openings 223. Consequently the back flow is all through the control openings 228 (arrow Y) leading to rapid retraction of the control piston 203 although the container remains inverted. Once the piston has returned to its rearmost position (now at the top) another dose can be dispensed by a further squeeze without having to bring the container upright. The mentioned back-flow also of course achieves a suck back of product from the nozzle region, preventing dripping between doses. In this embodiment the product is of a sufficiently low viscosity that, supplemented by the action of the valve 7, sufficient back flow is achieved through the control openings 228 to restore the mechanism for a further dose without a valved dump opening being needed. Accordingly the construction can be simplified and the rear wall 226 of the chamber component 202 is a fixed closed wall without any valve components. Having understood the principles involved, the skilled person will be able to contemplate other arrangements achieving the same effect in the same way. For example the valve element might be a flap rather than a free ring. Figs. 11 and 12 show such an embodiment. The insert cylinder or control chamber 302 is similar to that in Figs. 9 and 10, and its flow openings 323 are similarly disposed. However the valve component 307 is an annular flap valve, with an inwardly- directed flexible flap 372 connected integrally to a securing collar 371 that fits over an internal annular projection 324 of the cylinder insert. The flap 372 extends radially inwardly to the outer periphery of the outlet tube 344, which has a rearward shoulder 345 against which the flap can seat. Fig. 11 shows the condition during dispensing, with the flap opening under dispensing pressure to allow flow along the outlet path A while control flow B enters through the control openings 328 and the piston 303 advances correspondingly (arrow C) . Fig. 12 shows the situation when pressure on the resiliently squeezed bottle is released. The initial back flow in direction X immediately closes the flap valve against its seat shoulder 345, blocking this path so that all flow is back through the control openings 328 (arrow Y) restoring the piston 303 to its rearward/upward condition (arrow Z) without the need to bring the container upright. Further valve variants can easily be conceived. Individual valve elements might be provided for each flow opening. The valve may be differently positioned according to the outlet path construction; provided that it is upstream (in the dispensing sense) of the point where the outlet passage is to be blocked by the control piston it will still have the desired effect of confining return flow to a flow which restores the piston. Furthermore, the valved embodiment may also include a dump valve to speed return flow out of the chamber 29 and into the container, especially for more viscous products, provided that the valve will open under the reduced pressure provided by release of the squeezed container even when inverted. Or, it may not necessarily open when inverted but only when righted, providing an alternative operation mode. It should be appreciated that while a resilient squeezable container is the preferred and convenient embodiment, other forms of pressurised release or supply may also be effective. Also, while we have referred throughout to dispensing "liquid", the invention is applicable with fluid substances in general, such as gels and foams, and the term "liquid" should be interpreted accordingly.

Claims

CLAIMS :

1. A dosing device for dispensing metered doses of liquid from a container, the device defining a front discharge opening and having a control chamber positioned behind the front discharge opening, an outlet flow passage leading from past or around the control chamber to the front discharge opening by way of one or more flow openings adjacent the front of the control chamber, the control chamber having one or more rear control openings to admit a restricted flow of liquid into the control chamber from a container for said liquid on which the device is provided in use, and an obturator which is provided in the control chamber and relatively movable in the control chamber so as to advance, under the influence of said restricted flow of liquid into the control chamber behind the obturator through the control opening (s) in use, to a blocking position where it blocks the outlet passage to terminate a dose; a dump valve arrangement being provided at the back of the control chamber to allow liquid to escape more rapidly from the control chamber behind the obturator after a dose has been dispensed than liquid is able to enter the control chamber during dispensing via the control opening (s); characterised in that the dump valve comprises a dump valve seat and a dump valve member which make a convergent guiding engagement with one another, the dump valve member entering the dump valve seat to make a seal in a closed condition of the dump valve.

2. A dosing device according to claim 1 in which the dump valve member has a convex curved surface to make the sealing engagement.

3. A dosing device according to claim 2 in which the dump valve member is a ball.

4. A dosing device according to any one of claims 1 to 3 in which the dump valve member, discrete from the control chamber component, is retained in a cage at the back of the control chamber.

5. A dosing device according to claim 4 in which the cage is a discrete component joined to a rear end formation of the control chamber wall.

6. A dosing device according to any one of claims 1 to 5 in which the dump valve opening is central in the rear wall of the control chamber, with one or more said control openings disposed peripherally in relation to it,

7. A dosing device according to any one of the preceding claims comprising a front cap element through which the discharge opening is centrally defined, and providing a rearwardly-projecting tubular extension leading to the discharge opening and presenting a seat for the obturator to rest against in the blocking position.

8. A dosing device according to any one of the preceding claims in which the outlet path for liquid leads forwardly outside the control chamber and then radially inwardly, by way of said flow opening (s), around or through the front of the chamber wall to the discharge opening which is centrally disposed.

9. A dosing device according to any one of the preceding claims in which the obturator is a piston slidable in the control chamber.

10. A dosing device for dispensing metered doses of liquid from a container, the device defining a front discharge opening and having a control chamber positioned behind the front discharge opening, an outlet flow passage leading from past or around the control chamber to the front discharge opening by way of one or more flow openings adjacent the front of the control chamber, the control chamber having one or more rear control openings to admit a restricted flow of liquid into the control chamber from a container for said liquid on which the device is provided in use, and an obturator which is provided in the control chamber and relatively movable in the control chamber so as to advance, under the influence of said restricted flow of liquid into the control chamber behind the obturator through the control opening (s) in use, to a blocking position where it blocks the outlet passage to terminate a dose; characterised in that unidirectional valve means is provided to inhibit reverse flow in the outlet passage, whereby after a dispensing operation the return of liquid from the device to the container interior is selectively by flow back from the space in the control chamber behind the obturator, rather than by way of the outlet passage.

11. A dosing device according to claim 10 in which the unidirectional valve means is a flap valve or a free valve member movable in a valve space.

12. A dosing device according to claim 11 in which the valve has an annular valve member.

13. A dispenser comprising a dosing device according to any one of claims 1 to 12 on a container.

14. A dispenser according to claim 13 in which the container is resiliently squeezable.