GB2360273A

GB2360273A - Liquid dosing device

Info

Publication number: GB2360273A
Application number: GB0100857A
Authority: GB
Inventors: Anthony Charles Lammond Wass
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-01-18
Filing date: 2001-01-12
Publication date: 2001-09-19
Anticipated expiration: 2021-01-12
Also published as: GB2360273B; GB0001119D0; GB0100857D0; GB0026154D0

Abstract

A device for fitting to the neck of a deformable bottle to give a metered dose of liquid when the bottle is squeezed. The liquid passes through an elongate metering chamber 20, some being directed around or through a freely-moving shuttle 10 and thence through an outlet spout 30 but some being directed behind shuttle 10 to drive it away from the inlet end of chamber 20 and eventually close the outlet 28. Because it is configured so that all the liquid enters chamber 20 at its inward end, the chamber may fitted either inside or outside the neck of the bottle and the dose may be adjusted by moving the outlet closer to, or further from, the inlet.

Description

2360273 ROVED LIQUID DOSING DEVICE This invention relates to a device for

delivering a metered dose of liquid from a squeezable bottle. [Here and elsewhere 'squeezable bottle' means any closed container for holding liquid products which is temporarily deformable by manual pressure.] There are various known liquid metering devices for squeezable bottles, several using a ball or other form of obturator to close the outlet port once it has travelled the length of a metering chamber. Such a device is described in US Patent No. 3,146,919, filed in 1960, in one illustrated embodiment of which the obturator is a ball which is captive within the metering chamber and, when the bottle is upright, the ball closes a port leading from the main chamber of the bottle into the metering chamber. There are, however, a number of other ports connecting the two chambers but these are positioned part way along the metering chamber so that although, when the bottle is inverted and squeezed, the ball is driven towards the outlet, liquid can flow through the latter ports as well as through the former. This flow will be ahead of the ball until it has passed all the inlet ports, so that the volume of liquid dispensed will be more than the internal volume of the metering chamber.

1,5 The arrangement is therefore potentially capable of dispensing a large dose from a relatively small device. However the patent makes no claim for this feature and so does not indicate how it n-dght be optimised. A similar arrangement is described in US Patent No. 3,567,079, filed in 1968, but, like the earlier one, compactness is not the main object of the invention. It is, however, the prime object of UK Patent No. GB 2201395, which again uses the same > basic arrangement of a pilot and main ports into the metering chamber but incorporates 'a convoluted configuration whereby flow of liquid therethrough is directed partly back towards the obturator to exert a back-pressure thereon' and thereby, it is claimed, retard the obturator and allow a greater volume of liquid to pass through the main ports before they are closed.

21-5 Although each of these inventions should be capable of delivering accurately metered doses of a given liquid, none has found wide acceptance. In the case of the last named patent, of which 1 was coinventor, this is because the dose has been found to be constant only so long as there is no variation in either the viscosity or the surface tension of the liquid being dispensed or in the force with which the bottle is squeezed- The same is almost certainly -4o true of the other two inventions.

Apart from inconsistency of dose, the fact that all of the above devices require ports at both ends of the metering chamber means that they all suffer from the following inherent limitations: (a) they have to be configured so that they fit within the neck of the bottle, rather than be attached to the outside, (b) they can only provide a user- selectable dose by changing the ratio of pilot to main ports sizes, which is mechanically difficult as well as of doubtful accuracy, (c) they need a separate means of sealing the outlet to make the package 'shippable' and (d) they cannot completely empty the bottle.

The present invention differs from all the above devices in that it places all inlet ports at the opposite end of the metering chamber from the outlet. This not only simplifies the flow paths so allowing much better control of the flow ratios and hence much better consistency of dose but also (a) allows the device to be fitted either inside or outside the bottle, (b) the dose can be varied easily and accurately by altering the stroke, (c) the stroke can be reduced to zero, which effectively seals the outlet and (d) the bottle can be almost completely emptied as there is no need to provide a passageway around the metering chamber to the ports at the outlet end.

Essentially the invention comprises a liquid dosing device for fitting to the neck of a squeezable bottle comprising an elongate metering chamber having an inlet or inlets at one end connecting its interior to the inside of the bottle and an outlet or outlets at the opposite end through which liquid is dispensed, the chamber being divided into two by a freelymoving shuttle, which falls to the inlet end of the chamber when the bottle is upright and which is so configured that, when the bottle is inverted and then firmly squeezed, some of the liquid is directed through or around it, but some is directed into the cavity behind it, the ;to liquid which passes the shuttle (which can be called the main flow) being dispensed through the outlet(s) and the remainder (which can be called the pilot flow) driving the shuttle gradually to the opposite end of the chamber, where it occludes the outlet(s) and prevents any further dispensing of liquid until the process has been repeated.

In a first embodiment, the shuttle comprises a rigid central portion and a very flexible and 2.5' flaccid outer portion by which its periphery is sealed to the wall of the metering chamber while still allowing the central part to fall freely from one end to the other. A tubular spigot extends from the central portion of the shuttle through a hole in the inlet end of the metering chamber, the bore of the spigot passing through the shuttle to provide a passageway from the main chamber of the bottle into the chamber on the outlet side of the shuttle. The spigot has a small clearance all round it, which not only ensures free movement of the shuttle but also provides an annular orifice, which may form all or part of the total passageway from the bottle into the metering chamber on the inlet side of the shuttle; the total cross- sectional area of this passageway is normally smaller than the passageway through the shuttle. When the bottle is inverted and then firnfly squeezed, most of the liquid (i. c. the main flow) passes along the bore of the spigot into the outlet chamber and thence out of the spout but a proportion of the liquid (i.e. the pilot flow) is directed behind the shuttle and gradually carries it forward, the ratio of flows determining how much liquid is dispensed before the shuttle reaches the spout end of the metering chamber and closes off the outlet hole. It is preferably arranged that the passageways into the metering chamber on either side of the shuttle have similar flow characteristics and that the resistance to flow of the outlet is less than the total resistance of all the inlets, so that variations in liquid viscosity or surface tension or changes in the pressure applied to the bottle affect both passageways equally and therefore do not markedly change the ratio between their flows.

In a further embodiment, the chamber and shuttle are both of circular cross-section, the lo shuttle being in the form of a piston which allows little if any flow past its periphery but has a central hole which is in alignment with the inlet to the chamber and out of alignment with the outlet, the outlet preferably being at least as large as the inlet, and both being at least as large as the hole through the shuttle. When the bottle is inverted and squeezed most of the liquid (i.e. the main flow) passes straight through the shuttle and thence out of the spout but a proportion of the liquid (i.e. the pilot flow) is trapped behind the shuttle and gradually carries it forward, the ratio of hole sizes determining how much liquid is dispensed before the shuttle reaches the spout end of the metering chamber and closes off the outlet hole.

Experiment has shown that these embodiments can have a high magnification ratio (up to 10: 1) and dispense the same dose (to within plus or minus 10%) over a wide range of 21o liquids, regardless of how hard the bottle is squeezed. Unlike many other forms of magnifying doser, the components may be very simple mouldings, without the need for very close tolerances. Other features found in few if any alternatives are (a) the ability to alter the dose by varying the stroke, (b) complete emptying of the bottle and (c) rapid resetting after a dose has been dispensed.

2-5 By way of example, some embodiments of the invention are described below with reference to the drawings, all of which are vertical crosssections, showing the device attached to the neck of a bottle (most of which is not shown) by conventional means (which are not described but may be a snap fit as shown or a screw thread). For descriptive purposes 'up' and 'down' refer to the orientation when the bottle is upright and all components are assumed to be substantially circular in plan, as this is the most likely (though not essential) form in practice. Relevant details of the drawings are as follows:

Fig. 1 shows an embodiment in which the metering cell is a closed end cylinder and the shuttle a rolling piston, Fig. 2 shows the same embodiment after the bottle has been inverted and while it is being squeezed, Figs. 3 shows the same embodiment when the shuttle has reached the end of its stroke and has closed the outlet, 5- Fig. 4 shows an embodiment in which the shuttle is a simple piston with a tubular spigot passing through an inlet hole, Fig. 5 shows a similar embodiment with a piston-type shuttle having a more complex seal but no spigot passing through the inlet hole, and Figs. 6 to 8 show a similar embodiment to that shown in Fig. 5 except that the length of the lo metering chamber can be altered from one that gives a maximum dose, as shown in Fig.6, through a reduced dose (Fig. 7) to zero dose (Fig. 8).

With reference to Fig. 1, a dosing device 2 is mounted on the neck of a squeezable bottle 4, the device comprising three components: collar 6, body 8 and shuttle 10. The collar and body may be injection-moulded from rigid plastic materials and the shuttle from a more elastic material such as a rubber or a thermoplastic elastomer. The collar resembles a conventional closure cap in that it has a downwardly- extending skirt 12 which incorporates the means of attaching it to the neck of the bottle and a horizontal wall 14 which forms a seal 16 around the top of the neck. Unlike a closure, however, wall 14 has a substantiallysized hole 18 through it that connects the bottle with a metering chamber 20, formed between the upwardly-extending peripheral wall 22 of collar 6 and the downwardlyextending skirt 24 of body 8. The top of body 8 is a horizontal wall 26 having in it an outlet hole 28, which may simply pierce the wall or lead into a spout 30. As well as fitting securely together, collar 6 and body 8 trap between them the outer ring 32 of shuttle 10, this ring forming a seal between the two rigid components. The ring is connected by a thin 2s annular web 34 to a central annular plate 36 which is sufficiently thick to stop it flexing appreciably and just small enough in diameter to allow the web to roll freely between it and the bore 38 of the metering chamber. The web must be sufficiently flaccid that, when there is no liquid in the metering chamber, plate 36 can fall freely from one end to the other but sufficiently strong and impervious to prevent any passage of liquid or air from one side of the shuttle to the other, except via a passage 40 that runs through a spigot 42 extending downwardly from the middle of plate 36 and connects with a lateral hole or holes 44 passing through a closed-end spigot 46 on the opposite side of the shuttle. The shuttle therefore divides the metering chamber into two, both of which are independently connected to the main body of the bottle, that on the outlet side, chamber 48, by passage 40 and that on the inlet side, chamber 50, by an annular passage 52, formed by the clearance between spigot 42 and inlet hole 18.

When the bottle is inverted and then fim-dy squeezed, a flow of liquid is forced along passage 40 and thence via holes 44 and outlet chamber 48 to outlet 28. At the same time, a secondary flow reaches chamber 50 via passage 52 (augmented if necessary by one or more additional holes 54), so that shuttle 10 is gradually driven towards the outlet, as shown in Fig. 2, the ratio of the flows determining how much liquid is dispensed before the shuttle reaches the end of chamber 48, as shown in Fig. 3, when a conical face 56 on spigot 46 beyond holes 44 sealingly plugs outlet hole 28 and prevents any further flow.

When the bottle is returned to upright and pressure on it released, a partial vacuum is formed in the bottle which assists gravity in resetting shuttle 10 back to the position shown in Fig. 1.

The operation of all the other embodiments is exactly the sarne as that described above, although they vary in form. For example, the rolling shuttle seal of the first embodiment may be replaced by a labyrinth seal, as shown in Fig. 4, in which the skirt 60 of shuttle 10' is a close but clearance fit within a recess 62 formed between the skirts 12' and 24' of collar 6, and body 8' respectively, and, if the outlet hole 28' does not line up with it, passageway 40' through the shuttle may be a simple hole, as also shown in Fig. 4. The outlet is closed when the flat top 3 6' of the shuttle contacts the flat top 26' of the body.

It has been found that, with at least some liquids, it is not necessary to separate the flows being directed to either side of the shuttle physically so the shuttle 19' shown in Fig. 5 has no spigot to separate the flows passing through inlet hole IC but simply a hole W' which aligns with but is smaller in diameter than hole M' so that, in operation, some of the liquid passes straight through the shuttle into chamber 4W' and some is directed behind it into 2-5 chamber 50". Fig. 5 also shows how the possibility of air passing from chamber 4W' into chamber 5W can be further reduced by a more complex labyrinth than that shown in Fig. 4, with the shuttle 10" having a number of skirts 60' each closely fitting into a recess 62' in collar G'.

All the embodiments described above have a fixed dose and require some form of cap (which could be hinged to, and moulded integrally with, the body) to seal off the outlet and make the package 'shippable' but, in the version shown in Figs. 6 to 8, which requires no more parts, body 8... can be moved relative to collar 6... from a position in which metering chamber 20 (and hence the dose) is maxin-dsed, as shown in Fig. 6, via any number of intermediate positions, such as that shown in Fig. 7, which give smaller doses, to the one shown in Fig. 8, in which the dose is reduced to zero. In this position the outlet is permanently closed off, so there is no need for a'shipping' cap. An inwardly-directed annular rib 64 at the base of body 8... engages with the bottom edge 66 of collar 6.. to hold the body in the closed position and with one of a series of annular grooves 68 to hold it in a selected dosing position. The underside of body top 26' and top 36' of the shuttle both taper inwardly downwards so that any product remaining in chamber 20... drains back through shuttle hole 40... and is not squirted out of body hole 28... when the body is pushed /6 down to the closed position. In the closed position shuttle hole 40... is positively plugged by a small cylindrical projection 70 on the underside of body top 26'.

Claims

1. A liquid dosing device for fitting to the neck of a squeezable bottle comprising an elongate metering chamber having an inlet or inlets at one end connecting its interior to the inside of the bottle and an outlet or outlets at the opposite end through which liquid is dispensed, the chamber being divided into two by a freely-moving shuttle, which falls to the inlet end of the chamber when the bottle is upright and which is so configured that, when the bottle is inverted and then firmly squeezed, some of the liquid is directed through or around it, but some is directed into the cavity behind it, the liquid which passes the shuttle being dispensed through the outlet(s) and the remainder driving the shuttle gradually to the opposite end of the chamber, where it occludes the outlet(s) and prevents any further /0 dispensing of liquid until the process has been repeated.

2. A dosing device as in claim 1 in which there is a passage through the shuttle but a peripheral seal prevents any significant flow around it.

3. A dosing device as in claim 2 in which the peripheral shuttle seal is a flexible membrane.

4. A dosing device as in claim 2 in which the peripheral shuttle seal is a labyrinth formed between the walls of the shuttle and those of the metering chamber.

5. A dosing device as in any preceding claim in which the flows from the bottle into the chambers behind and beyond the shuttle are conducted along separate passageways

6. A dosing device as in any claim 1 to 4 in which the flow through the shuttle is not physically separated from the flow into the chamber behind it.

2-o

7. A dosing device as in claim 6 in which the chamber and shuttle are both of circular cross-section, the shuttle having a central hole which is in alignment with the inlet to the chamber and out of alignment with the outlet, the outlet being at least as large as the inlet, and both being at least as large as the hole through the shuttle.

8. A dosing device as in any preceding claim in which the distance between the inlet and.2!!;" outlet may be altered to vary the size of the dose or close the outlet.

9. A dosing device as in any preceding claim, in which the device is fitted with an integral or removable lid.

f.

Amendments to the claims have been filed as follows CLAIMS 1. A liquid dosing device for fitting to the neck of a squeezable bottle comprising an elongate and preferably cylindrical metering chamber having an inlet or inlets at its inward end to connect its interior to the inside of the bottle and an outlet or outlets at its outward end through which liquid is dispensed, the chamber being divided into two by a freelymoving shuttle, which falls to the inlet end of the chamber when the bottle is upright, the chamber and shuttle being so configured that, when the bottle is inverted and then firmly squeezed, the liquid which is forced into the metering chamber, is divided into a main flow component, preferably the major portion of the whole, which passes through or around the shuttle but substantially by-passes the chamber behind it, this flow then being discharged through the outlet(s), and a pilot flow component, preferably a minor portion of the whole, which feeds into the chamber behind the shuttle but is substantially prevented from passing to the outlet side of the shuttle, so that although the shuttle tends to be moved by the viscous drag or impact of the flow of liquid upon it, any such movement expands the chamber behind it, thus creating a partial vacuum within it which prevents the shuttle expanding the chamber faster than the secondary flow can fill it, and thereforc the. ra-tio of main to pilot flow components determines the rate at which the shuttle will move and hence how much liquid is dispensed before the shuttle reaches the far end of the metering chamber, where it occludes the outlet(s) and prevents any further dispensing of liquid until the process has been repeated, 2. A dosing device as in claim 1 in which there is a passage through the shuttle but a peripheral seal prevents any significant flow around it.

5. A dosing device as in any preceding claim in which the flows from the bottle into the chambers behind and beyond the shuttle are conducted along separate passageways 6. A dosing device as in any claim 1 to 4 in which the flow through the shuttle is not physically separated from the flow into the chamber behind it.

8. A dosing device as in any preceding claim in which the distance between the inlet and outlet may be altered to vary the size of the dose or close the outlet.