GB2037255A - Metered dispensing of liquids - Google Patents

Abstract

A container 1 from which liquid is dispensed has a metering chamber 15 arranged at its mouth. A metering device is arranged to cooperate with the outside of this metering chamber to control the amount of liquid allowed to flow out. The flow can be controlled either by determining the time for which the metering device opens the metering chamber, or by constructing the metering chamber as a pump chamber of a specified volume so that the metering device pumps the liquid out of the chamber and therefore dispenses a predetermined volume. In the second method, the metering chamber includes an axially compressible bellows portion 19 which forms a pump chamber. Non-return valves 18, 22 are provided at both ends of the pump chamber, and the metering device comprises plates on either side of the bellows section which can be drawn towards one another to squeeze the bellows section 19. <IMAGE>

Description

SPECIFICATION Metered dispensing of liquids The invention relates to the metered dispensing of liquids, and in particular to a dispensing system comprising a container and a metering device, and to a container for use in such a system.

The apparatus serves in particular for metered dispensing of easily perishable organic liquids. For these, disposable packages are preferably used in order to avoid bacteriological or like soiling problems due to insufficient cleaning of the transport or storage containers. Such metering devices are known in which it is merely necessary to connect the metering device sealingly to the disposable package.

The delivery is effected under time or volume control. Once the package is empty, it is discarded and a new, full package is connected to the metering device.

Now although the disposable package helps to avoid soiling problems or infections or the like because it is discarded after use, the metering device is used time and again, and becomes soiled and difficult to clean so that the advantages aimed at become only partly effective in practice.

According to the invention, there is provided a system for metered dispensing of liquids, comprising a container and a metering device, the container comprising a neck portion, a metering chamber connected to the neck portion for receiving liquid from the container and a delivery opening from the chamber for discharge of metered quantities of liquid, the metering device being adapted to cooperate with the external wall of the metering chamber to close the delivery opening when said metered quantity has been discharged.

With this system, the metering device does not come into contact with the liquid at any time. In this way soiling of the metering device by the liquid is impossible. On the other hand, soiling of the metering device cannot produce any effect on the liquid since the latter passes through the metering device in a contact-less manner.

Advantageously a vent tube is permanently built into the disposable container. During storage of the container, the inlet opening of the vent tube, in the bottom of the container may be hermetically sealed by a releasable closure, e.g. a tear-off closure. In operation, the vent tube introduces air into the container close to the neck thereof, so that the boundary surface between the air and the liquid lies close to the removal opening. This is necessary for time-controlled metering independent of the liquid level in the container.

In some cases it may be sufficient to introduce air merely into the head space of the disposable container. Preferably the container is provided near the neck portion with a storage recess in which prior to use of the container, the metering chamber is located in a folded state, so that it is protected during transport or during storage of the container and sealed by a container closure closing the recess. The metering chamber preferably includes a tubular member consisting of a flexible, preferably elastic material, and of sufficient length for it to be drawn through the metering device when the container closure has been opened. In one embodiment, the tubular member may be placed in a spirally folded manner in the storage recess, so that it can easily be pulled out after the closure has been opened.The free end of the tubular member may be in the form of an outlet nozzle with reduced cross-section. The metering chamber may consist of a natural rubber or another material which is inert with respect to the liquid. The storage recess may be hermetically sealed to the outside by a screw or a tear-off container closure.

The metering chamber is preferably in the form of a corrugated bellows section.

The metering device may comprise a sleeve-like or ring-like or piston like armature through which the tubular member, attached to the bellows section, is drawn for the purpose of putting the container in the operative position. The ring-like armature can be moved in the direction of the axis of the tubular member from a lowered position to a raised position by means of an actuating device. Advantageously the ring-like armature co-operates with an electromagnetic actuating device.

In the lowered position the ring-like armature may actuate a clamping device which is arranged at a level slightly above the outlet nozzle of the tubular member and which can clamp the tube closed. The actuation of the clamping device occurs preferably by the weight of the ring-like armature so that in the case of an electro-magnetic actuating device the tube is automatically closed upon failure of the current.

When the ring-like armature is moved to the raised position by its actuating device, the clamping device is released and the tube opens to release a flow of liquid. The opening of the jaw-like clamping device may be effected for example under the static pressure of the liquid. Alternatively, however, the jaws may be associated with resilient return elements.

When, in the manner previously described, the static pressure of the liquid in the tubular member is always maintained constant, accurate metering of the liquid from the container can be obtained directly by time control of the actuating device for the ring-like armature. The metered liquid may be introduced directly into a vessel placed in readiness, or into a mixing device, without the liquid coming into contact with the metering device. It is not therefore necessary to clean the metering device or to subject it to continuous hygienic supervision.

The embodiment described may be employed with advantage where substantial changes of the viscosity of the liquid are unlikely to occur. Such conditions arise, for example, in cases in which perishable liquids are maintained continuously at the same temperature by cooling the containers, so that the temperature of the contents remains within narrow limits and cannot have a significant effect on the viscosity of the liquid or on the accuracy of the metering.

In a preferred embodiment, a plate is arranged on either side of the bellows section, and these plates are drawn together, for example by a magnetic force, to squeeze the bellows section and expel liquid contained in the bellows section out of the delivery opening. This embodiment does not therefore make use of timed operation of the metering device; instead, the volume dispensed is determined by the internal volume of the bellows section, and the movement of the plates toward one another. One of the plates is preferably provided with an electromagnetic coil, and the other plate is made of a magnetic material so that on actuation of the coil the two plates are moved together. Either one of the plates may be fixed, so that the other plate is drawn towards the fixed plate.Stops may be provided to limit the travel of one plate towards the other so as to control the quantity of liquid dispensed. The volume of liquid dispensed is therefore independent of the viscosity, and this embodiment can therefore be used for liquids which do not require cooling, e.g.

self-preserving syrups or concentrates, i.e. liquids with a very high sugar or salt content. The viscosity of such liquids is influenced to a considerable extent by temperature fluctuations, but such fluctuations will not cause inaccuracies in the volume dispensed if this embodiment is used.

Valves are preferably provided between the metering chamber and the container and between the metering chamber and the external atmosphere.

These valves should be non-return valves arranged so that the valve between the container and the metering chamber opens automatically to admit liquid to the metering chamber when the pressure in the chamber drops below that in the container.

When the pressure in the chamber is higher than that in the container, the valve closes. The valve between the chamber and the external atmosphere opens when the pressure in the chamber rises above the external pressure, to dispense liquid, and closes when the pressure in the chamber drops below the external pressure. A pumping effect is therefore achieved as the bellows is compressed and allowed to expand. Once the electromagnetic coil has been switched off, it is necessary that the bellows should once again expand. To this end, the bellows may be of material which is sufficiently resilient to provide the restoring force expanding the bellows. Alternatively, an auxiliary spreader spring may be provided to supply the restoring force. In a preferable embodiment, the electromagnetic coil is positioned underneath the bellows and moves towards an upper, stationary plate.When the current is switched off, the coil drops under the influence of gravity and draws with it the lower side of the bellows, to open the bellows.

In this embodiment where delivery is controlled by a volume, perfect hygienic operation is again ensured because the liquid does not come into contact with the metering device at any time. This embodiment has the advantage that temperature effects which influence the viscosity of the liquid do not affect the volume dispensed.

Since the containers for use with the metering device will be made and sold separately from the metering device, the present invention also provides a container from which liquids can be dispensed in metered quantities by means of a metering device, the container comprising a neck portion, a metering chamber connected to the neck portion for receiving liquid from the container and a delivery opening from the chamber for discharge of metered quantities of liquid.

The metering chamber preferably includes an axially compressible bellows section.

The invention will now be further described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is an axial sectional view through a container according to the invention; Figure2 is an axial sectional view through a metering device; Figure 3 is a plan view of part of the metering device of Figure 2; Figure 4 is an axial sectional view of an alternative metering device; and Figure 5 is a detail view of part of the container of Figure 1, in the storage condition.

The container illustrated in Figure 1 is a disposable or one-time package for containing liquids to be dispensed in metered quantities. The container is shown in a position immediately prior to use, and may consist of, for example, a synthetic resin. In the illustrated example, it comprises a body having a dished bottom 4 which points upwardly in the dispensing position illustrated in Figure 1. In the illustrated position, the top of the body terminates in a slightly narrowed neck section 7 which extends like a collar from an intermediate wall 8 and bounds an accumulation chamber 9 the purpose of which will be described below in detail. The collar-like neck section 7 terminates at the top in an end face 10.

The container shown in Figure 1 is filled with a liquid 2 to be dispensed. The liquid level in the illustrated position is denoted by 2a. A head space la exists above the liquid level. The interior of the container must be vented if the liquid is to flow out.

For this purpose a vent tube 3 may be fixed in the bottom 4, and sealed outwardly at 1 2a by a tear closure. The tube extends over most of the height of the container to a position close to the container neck 7. When liquid is being dispensed, the lower end 1 2b of the tube determines the boundary surface between the liquid and the outer atmosphere and thus the pressure acting on the liquid above the intermediate wall 8 of the container neck. This kind of venting offers certain known advantages. In some cases these advantages are not important, and a short tube 5 (indicated by a broken line) may be fixed in the bottom 4 instead of the tube 3. In use, the short tube 5 terminates in the head space la.

The intermediate wall 8 has an opening 17 which may be disposed centrally or eccentrically. An additional container member 15 is sealed to the edge of the opening.

The additional container member 15 may be a simple flexible tube which is in free communication with the interior of the container 1 and comprises at its lower end a tear-open closure. Such an embodiment is not illustrated. When the container is stored, the tube is spirally wound up in the accumulation chamber 9 of the container neck, and the accumulation chamber is closed outwardly by a tear-open closure. To put the container into use, the accumulation chamber closure is opened and the tube is pulled out and threaded through an electromagnetic actuating device to such an extent that the closed lower end of the tube projects beyond the underside of the device.In this case the end of the tube is threaded through two clamping jaws or another clamping device actuable by the electromagnetic device which shuts off the lower end of the tube, by clamping, when the magnetic device is switched off. The tear-off closure at the lower end of the tube may then be removed to open the lower end of the tube without liquid flowing out. The clamping device may be opened by actuation of the electromagnetic device, so that the liquid is directly delivered from the tube without coming into contact with the actuating device or the clamping device.

The duration of the actuation of the electro-magnetic device determines in this case the quantity of liquid flowing out.

In the illustrated preferred embodiment, an electro-magnetic actuating device is used, in addition to a closure device for the tube, for the production of a pumping effect.

For this purpose, the additional container member 15 according to Figure 1 comprises a resilient, axially compressible portion 19 which can be compressed to alter its volume. This compressible portion 19 is hermetically sealed to the edge of the opening in the intermediate wall 8 by means of a connecting section 16, and terminates in a narrow tube portion 20 which can be threaded through a metering device 25, which will be described with reference to Figure 2 and Figure 4.

An automatic closing device is arranged in the inlet opening 17 of the connecting section 16 of the container member 15. In the illustrated example this is a non-return valve which is constructed like a duck's beak and is held in the closed position by elastic deformation forces; when pressure differences occur on the two sides of the valve, it either opens or closes, depending upon the direction of the pressure drop.

The resilient, axially compressible section 19 is preferably constructed in the form of a cylindrical corrugated bellows section which has a diameter nearly as large as that of the accumulation chamber 9. The free end of the tubular section 20 is connected to a further closure device 22 of any desired kind.

Preferably this is also contructed as a beak-shaped non-return valve, like the valve 18. Before the container is put into use, the beak-like section is extended and its free end is welded closed or permanently closed in some other way, e.g. by a cover section 23. To put the container into use, the section 23 may be torn off along a weakened line or cut off by means of a tool, so that the non-return valve section 22 is able to function.

The electro-magnetic metering device 25 shown in Figure 2 comprises a housing 30, 32 which can be connected by means of devices not illustrated, e.g. a quick-action connector, to the correspondingly constructed collar 7 of the container 1. A hermetic connection between the two is not necessary. Prior to the attachment of the housing 30, 32, the connector section 16 of the additional container member 15 is elastically extended or pulled to the side, so that a plate-shaped armature disc 26 (Figure 3), which has a radial slot 35, can be pushed over the connector section 16 and arranged above the corrugated bellows section 19 within the collar 7 of the container neck. The underside of the corrugated bellows 19 rests upon a countersurface 26a of the housing 30, 32 located opposite the armature plate 26. An electro-magnetic coil 31 is arranged in the housing.

The lower narrowed portion of the housing 32 may be used for an electro-optical monitoring device for monitoring the liquid level in the container. The housing 30,32 and the coil 31 define a passage extending parallel to the container axis, for the tubular section 20 of the container member 15.

The corrugated bellows section 19 shown in Figure 2 is constructed from a material with a wall thickness and a predetermined starting shape such that the resilience of the corrugated bellows 19 is sufficient to raise or maintain, respectively, the armature plate 26 against gravity in the starting position illustrated in Figure 2, when the electromagnetic coil 31 is switched off. When the latter is switched on, the armature disc 26 is pulled in the direction of the magnet coil 31 and the counter surface 26a; the length of the stroke 28 may be predetermined by spacer members 27. Since the connector section 16 is elasticaily longitudinally extensible, the corrugated bellows section 19 may be axially compressed by the armature plate 26 and the liquid located in the container member 15 may be pressed out of the tube section 20 causing the valve beak 22 to open.The quantity of liquid dispensed is determined exclusively by the volumetric change of the corrugated bellows section 19 and by the pressure differences caused thereby. In this case the upper valve 18 remains closed. After the coil 31 has been switched off, the armature plate 26 is raised again into the starting position under the effect of the resilience of the corrugated bellows 19.

The valve 22 closes and the upper beak valve 18 opens because of the underpressure produced in the container member 15, so that liquid can flow from the container 1 into the container member 15. An additional spreader spring may be provided between the counter surface 26a and the armature plate 26 when the resetting force of the corrugated bellows 19 is insufficient.

In every case the wall material of the additional dontainer member 15 is so constructed that the strength is sufficient to exclude any expansion of the wall of the container member when the container member is compressed so that an exactly predeterminable volume change is ensured by the axially compressible section. In order to avoid pressure changes upon the corrugated bellows due to different liquid levels in the container 1, the container 1 should be vented by means of a deeply immersed vent tube 3 according to Figure 1. However, if the restoring force of the corrugated bellows due to the resilience of the bellows or the presence of a spreader spring is sufficiently large, venting is also possible by means of the tube 5 shown in Figure 1, which only vents the head space 1a.

During packaging and during the transport and storage of the container 1, the corrugated bellows 19 is axially compressed and the tube section 20 is folded together on the underside of the compressed corrugated bellows, so that the unit is accommodated in the accumulation chamber 9 of the container neck, as shown in Figure 5. The accumulation chamber is closed outwardly by a tear-off cover 50.

The sealed section 23 which may be cut off or torn away ensures, independently of the container closure 50, easy connection of the container to an actuating device and hygienic packaging of the liquid prior to initial use of the device.

In the embodiment shown in Figure 4 spacer members 40 provide that the armature plate 26 is supported at a predetermined constant spacing from the end face of the housing 41. In contrast the coil is received in a coil housing 42 which is axially movable within the housing 41, as indicated by the double-headed arrows. The upper side of the coil housing forms the counter surface which cooperates with the stationary armature disc 26. In this case, the coil housing 42 is pulled against the armature plate 26 upon energisation of the coil, and in this way the corrugated bellows is compressed axially. The downward movement of the coil housing 42 is limited by fixed or movable abutments 43 in the housing 41. Preferably the coil housing is connected to the lower end of the corrugated bellows, so that the weight of the coil contributes to the extension of the corrugated bellows after deenergisation of the coil. In the case of a highly viscous liquid the Figure 4 embodiment assists the liquid to flow quickly under the increased suction effect from the container 1 into the container member 15 when the coil is de-energised.

Claims (27)

1. A system for metered dispensing of liquids, comprising a container and a metering device, the container comprising a neck portion, a metering chamber connected to the neck portion for receiving liquid from the container and a delivery opening from the chamber for discharge of metered quantities of liquid, the metering device being adapted to cooperate with the external wall of the metering chamber two close the delivery opening when said metered quantity has been discharged.

2. A system as claimed in claim 1, wherein, in use, the delivery opening is arranged below the metering device.

3. A system as claimed in claim 1 or claim 2, wherein the metering chamber is a deformable tubular member which includes a portion extending through an opening in the metering device, the delivery opening being arranged at the free end of said portion.

4. A system as claimed in claim 3, wherein the tubular member includes at least one resiliently deformable portion.

5. A system as claimed in any preceding claim, wherein a closure device, actuable by a set of clamping jaws forming part of the metering device is provided at the delivery opening of the metering chamber.

6. A system as claimed in any preceding claim, wherein a valve is provided between the container and the metering chamber, which valve opens when the pressure in the chamber drops below that in the container and closes when the pressure in the chamber rises above that in the container.

7. A system as claimed in any preceding claim, wherein a valve is provided at the delivery opening of the metering chamber, which valve opens when the pressure in the chamber rises above the external pressure and closes when the pressure in the chamber drops below the external pressure.

8. A system as claimed in claim 6 or claim 7, wherein said valves are beak-like valves which are biassed into a closed position and open automatically under the influence of pressure.

9. A system as claimed in claim 3 or claim 4 wherein the tubular member comprises at least one corrugated bellows section which is deformable in an axial direction.

10. A system as claimed in claim 9, wherein the metering device comprises a plate on either side of the bellows section, and means which can be actuated to draw the plates together to compress the bellows section and expel liquid from the bellows section through the delivery opening.

11. A system as claimed in claim 10, wherein the resilience of the bellows section is sufficient to push the plates apart when said means is not actuated.

12. A system as claimed in claim 10 or claim 11, wherein said means for drawing the plates together comprises an electromagnetic coil associated with one plate, which coil, when energised, attracts the other plate.

13. A system as claimed in claim 12, wherein said other plate is fixed and the electromagnetic coil and said one plate are drawn towards said other plate when the coil is energized.

14. A system as claimed in any one of claims 9 to 13, wherein the corrugated bellows section is connected to the container neck portion by an extensible connecting section.

15. A system as claimed in any one of claims 12 to 14, wherein a tubular portion, extending through the electromagnetic coil, connects the bellows section to the delivery opening.

16. A system as claimed in any preceding claim, wherein the metering chamber is stored in a recess formed around the container neck portion and covered, during storage, by a closure.

17. A disposable container from which liquids can be dispensed in metered quantities by means of a metering device, the container comprising a neck portion, a metering chamber connected to the neck portion for receiving liquid from the container and a delivery opening from the chamber for discharge of metered quantities of liquid.

18. A container as claimed in claim 17, wherein the metering chamber is a deformable tubular member, and the delivery opening is arranged at the free end of said member.

19. A container as claimed in claim 17 or claim 18, wherein a closure device is provided at the delivery opening of the metering chamber.

20. A container as claimed in claim 17 or claim 18, wherein a valve is provided between the container and the metering chamber, which valve opens when the pressure in the chamber drops below that in the container, and closes when the pressure in the chamber rises above that in the container.

21. A container as claimed in claim 20, wherein a valve is provided at the delivery opening of the metering chamber, which valve opens when the pressure in the chamber rises above the external pressure and closes when the pressure in the chamber drops below the external pressure.

22. A container as claimed in claim 20 or claim 21, wherein said valves are beak-like valves which are biassed into a closed position and open automatically under the influence of pressure.

23. A container as claimed in any one of claims 17 to 22, wherein the metering chamber is a corrugated bellows section which is deformable in an axial direction.

24. A container as claimed in claim 23, wherein the corrugated bellows section is connected to the container neck portion by an extensible connecting section.

25. A container as claimed in any one of claims 17 to 24, wherein the metering chamber is stored in a recess formed around the container neck portion and covered, during storage, by a closure.

26. A system for metered dispensing of liquids, substantially as herein described, with reference to Figures 1, 2,3 and 5 or with reference to Figures 1,3, 4 and 5 of the accompanying drawings.

27. A container from which liquids can be dispensed, substantially as herein described, with reference to Figures 1,2,4 and 5 of the accompanying drawings.