Technical Field

The present invention relates to a dispensing device for powders. As used herein, the term "powders" includes any free-flowing divided or granulated dry materials, whether regular or irregular in shape. The powders may be of a wide variety of materials or mixtures of materials e.g. detergent powders, foodstuffs, granulated pet foods, fertilisers.

Background Art

Any discussion of the prior art throughout the specification is not an admission that such prior art is widely known or forms part of the common general knowledge in the field.

Small quantities of powders (e.g. household detergent powder, cereals) often are sold in cardboard cartons and dispensed from the cartons by punching or tearing a hole in the upper side of the carton, and pouring the contents out. It can be difficult to estimate the quantity being poured out, and if a reasonably exact measure of the quantity of powder to be dispensed is necessary (for example as in the case of detergent powder) then the powder has to be poured into a separate measure. This can be both messy and time-consuming, and the measure has to be stored separately.

Larger quantities of powders (e.g. commercial detergent powders, fertilisers) generally are sold in sacks or tubs, and the required quantity of powder is scooped out using a separate measure. This means that the user's hand comes in contact with the powder; for many of the powders being dispensed, frequent skin contact is undesirable, so the user has to wear protective gloves. If the packaging does not include a suitable measure, then the user has to provide one. This method of dispensing powder is becoming increasingly popular even for small quantities of powders.

A number of different dispensing devices for powders have been proposed, as discussed below. In considering the merits of the designs as discussed below, it should be borne in mind that dispensing devices for powders commonly would be incorporated into the container in which the powder was sold. Since a majority of the powders to be dispensed are relatively low cost (e.g. detergent powders, food stuffs) the dispensing device must not significantly add to the cost of the container. Further, a majority of the relevant containers are made of opaque materials (e.g. cardboard or plastics materials) and the dispensing device cannot be seen by the user. It follows that the dispensing device must operate reliably when the container is tipped to dispense a metered amount of the contents: - if the dispensing device is such that the container has to be oriented in a non-standard position (for example inverted well beyond the usual tipping position) then if a user forgets or ignores the operating instructions for the dispensing device, the correct amount of powder will not be dispensed the next time the container is used, but the user has no means of knowing this, because the amount of powder to be dispensed cannot be seen.

Italian patent TO 2002/0080 discloses a container dispenser device for grain products which provides a container fitted with a zigzag dispensing channel along one side of the container. This is a relatively complex, and therefore expensive, device which provides multiple metering gaps and a twisting delivery path, which in itself can pose problems if the powder to be dispensed is hygroscopic, because the delivery path is easily clogged. A further drawback is that the container has to be completely inverted to clear the metered amount of product from the dispensing channel; that is, the container has to be tipped well beyond the normal tip position to dispense the correct amount. An additional drawback is that the dispensing channel is filled with the metered amount of product while the container is being tipped, so that if the container is tipped very rapidly, the correct amount of product will not be dispensed because it will not have sufficient time to enter the dispensing channel.

US patents 279 9436 and 466 7857 both disclose containers with metering devices made of a series of spaced partitions; the partitions are secured across the width of the container in a stack. Both devices are relatively complex, and therefore expensive to manufacture.

US patent 493 8394 discloses a somewhat simpler arrangement, in which the metering device is formed by a pair of inclined surfaces, which together with the base of the container provide two metering gaps through which material must be passed before it can reach the dispensing channel. However, the design has the drawback that once the level of powder remaining in the container falls below the upper metering gap, it is difficult for powder to flow into the dispensing channel, so that the device is unlikely to dispense a correctly metered amount once the contents reach this level. Even when there is a large quantity of powder in the container, the container has to be completely inverted to ensure that powder enters the upper metering gap: - simply tipping the container to the normal tip position (an inclination of about 130 ° - 140° to the vertical storage position) will not reliably fill the metering device.

US 289 6826 discloses two different designs of measuring dispenser:- the embodiment shown in figures 1 and 2 is very simple indeed, being basically a dispensing channel formed along one side of the container, with a small deflecting surface at the lower end of the channel. However, this embodiment provides nothing to meter material into the dispensing channel, and the discussion in the specification states that if the container is too full, the metering device simply does not work and the contents of the container can pour out without any metering at all, when the container is tipped. Further, there is nothing to direct material towards the dispensing channel, and it is unlikely that the device would work when the contents of the container were low.

The second embodiment disclosed in this patent provides an additional partition spaced from the dispensing channel and providing two aligned metering gaps, to meter material into the dispensing channel. However, the additional partition is parallel to the side of the dispensing channel, so that for material to pass through the metering gaps, the container has to be tipped well beyond the angle necessary for dispensing product from the channel, especially when the contents of the container is low; otherwise, product will not pass through the metering gaps.

EP 069 6541 discloses a metering arrangement which is located just below the top of the container i.e. just below the opening of the dispensing channel. This has the obvious advantage of keeping dispensing channel short, but has the drawback that to pass through the metering gaps formed between, firstly, one end of the metering device and the top of the container and, secondly, the base of the metering device and the end of the dispensing channel, the container has to be tipped well beyond the position required for simply tipping product out of the dispensing channel: - it is necessary to tip the container to about 180° - 240° to the vertical to ensure that the correct amount of product passes the metering gaps. Disclosure of Invention

An object of the present invention is the provision of a dispensing device for a container of powdered material which overcomes the above described drawbacks or at least provides a useful choice.

The present invention provides a powder dispensing device for use in combination with a container, said dispensing device including:

- a dispensing channel which extends from a lower end which in use is spaced above the bottom of the container to an upper end at or adjacent to the top of the container;

- the lower end of the dispensing channel being open and the upper end of the dispensing channel being able to be opened;

- a metering device which in use is secured to the bottom of the container;

- said metering device including first and second sloping surfaces having upper edges which are joined together and lower edges which are arranged in use to contact the base of the container at an acute angle;

- the lower edge of the first sloping surface lying adjacent the lower end of the dispensing channel, and the lower edge of the second sloping surface lying further from the dispensing channel than said lower edge of the first sloping surface;

- the first sloping surface being inclined away from the dispensing channel such that the upper edge of the first sloping surface is further away from the dispensing channel than the lower edge of the first sloping surface, and the distance between the lower end of the dispensing channel and said first sloping surface providing a metering gap which in use meters the quantity of material which can pass from the container into the dispensing channel.

Preferably said dispensing channel provides a substantially linear dispensing path.

The dispensing channel may be of constant or tapered cross-section.

The dispensing device may be made separately for insertion into a powder container or may be formed integrally with the container. In the latter case, the metering device may be formed integrally with the bottom of the container. The container and/or the upper end of the dispensing channel may be formed with closeable apertures.

The dispensing channel may be fitted with a removable baffle or plug to close off the lower end of the channel during transport.

Brief Description of Drawings

By way of example only, a preferred embodiment of the present invention is described in detail with reference to the accompanying drawings in which:- Figure 1 is an isometric view of a container incorporating a dispensing device, in accordance with the present invention;

Figure 2 is a side view of the container of Figure 1 , with the container empty;

Figure 2a is a plan view of Figure 2;

Figure 3 is a side view of the container of Figure 1 , showing the container being filled with powder to be dispensed;

Figure 4 is a side view of the container of Figure 1 , showing the container being tipped towards the dispensing position;

Figure 5 is a side view of the container of Figure 1 , showing powder being dispensed from the container;

Figure 6 is a side view similar to Figure 2, but with the baffle partly withdrawn;

Figure 7 is a side view of a second embodiment of the invention; and

Figure 8 is a longitudinal section through the container of Figure 7.

Best Mode of Carrying out the Invention

The embodiment shown in Figure 1 -6 of the drawings illustrates a container incorporating a dispensing device which has been formed integrally with the container; a container of this type could be sold pre-filled with powder, but the container actually shown in the drawings is designed to be filled with powder from a larger container, so that the dispensing container can be reused.

Referring to the drawings, a container 10 incorporates a dispensing device 1 1 ; the container 10 is depicted as rectangular in cross-section, but both the container and the dispensing device may be any of a wide range of cross-sectional shapes. The dispensing device 1 1 includes a dispensing channel 12 formed between two opposed walls 13, 14 which are spaced apart by a width a (Figure 2). In the drawing, the width a is shown as being constant (i.e. the walls 13, 14 parallel) but this is not essential - the walls 13, 14 may be inclined towards or away from each other to provide a tapered dispensing channel 12. However, it is preferable that the dispensing channel 12 is linear, and is smooth sided, because any changes in angle or changes in the shape of the dispensing channel will constrict the flow of powder being dispensed. In the embodiment shown in the drawings, the wall 14 is also a wall of the container 10, but it will be appreciated that the wall 14 could be formed by a separate wall inserted into the container.

The dispensing channel 12 extends across the full width of the container:- the wall 13 is secured down each of its longitudinal edges 15, 16 to the adjacent front and rear walls 17, 18 of the container. The lower end 19 of the dispensing channel 12 is located a short distance above the base 24 of the container; the upper end 19a of the dispensing channel lies flush with the top 24a of the container. The lower and upper ends 19, 19a are open, but the upper end 19a may be provided with a removable cap or seal for transport purposes.

The dispensing device 1 1 further includes a metering device 20 in the form of an angled plate secured across the full width of the container, with the edges of the plate secured to the walls 13, 14 of the container. The device 20 provides two surfaces 21 , 22 the planes which are perpendicular to each other, so the device is triangular in cross-section. The device is positioned in the container with the edge 23, which forms the highest point of the device, furthest from the base 24 of the container, and extending above the lower end 25 of the wall 13. The free edges 27, 28 of the corresponding surfaces 21 , 22 are secured to the base 24 of the container. The position of the metering device 20 in the container is such that the edge 23 lies closer to the longitudinal centre line of the container than the wall 13, and the lower edge 28 contacts the base 24 of the container adjacent the lower end of the dispensing channel 12.

It should be noted that the surface 21 need not be perpendicular to the surface 22:- the angle between these two surfaces is not important. However, it is important that the surface 22 is inclined away from the dispensing channel 12, and that the surface 21 is inclined towards the dispending channel, i.e. angles X and Y (Figure 2) both must be acute angles. The smaller the angle x, the greater the amount of powder which can pass into the dispensing channel for each dispensing cycle.

If the surface 21 is perpendicular to the surface 22, or angle Y is an obtuse angle, powder could lodge behind the surface 21 and fail to dispense from the container.

If the filled container is tipped or inverted during transport, an excessive amount of powder could enter the dispensing channel 12, so that the first quantity of powder delivered by the container when it is initially used would be more than expected. To prevent this, the container is fitted with a pull-out baffle 35, as shown in Figures 2, 2a and 6 only. The baffle is shown in broken lines in Figure 2. The baffle 35, in the position shown in Figure 2, blanks off the space between the lower end 25 of the wall 13 and the edge 28 of the metering device 20, and thus prevents powder from entering the dispensing channel 12, irrespective of the orientation of the container.

The baffle 35 is channel-shaped in cross section:- as shown in Figure 2a, the baffle consists of a back 36 with two side walls 37,38 parallel to each other and at right angles to the back 36. If the dispensing channel 12 is the same width all the way down, then the walls 37,38 are of uniform height all along their length; if the dispensing channel 12 is tapered, then the walls 37,38 are tapered as necessary, to fit. The only function of the walls 36,38 is to prevent the back 36 from falling away from contact with the wall 13.

The baffle 35 is secured in position in the channel 12 by any suitable means, e.g. a removable adhesive seal securing the top of the baffle 35 to the top 24a of the container. Before the container is used for the first time the baffle 35 is pulled out (see Figure 6) and discarded, to allow powder to flow into the dispensing channel 12 as described below.

The top 24a of the container is formed with a filling aperture 29, through which the container may be filled with powder, for example using a funnel 30 as shown in Figure 3. Once the container has been filled, the aperture 29 is sealed by a removable plug 31 . Alternatively, the filling aperture 29 and plug 31 may be omitted, and the top 24a of the container may be formed with any suitable design of openable top or lid, to allow the container to be filled with powder. Another possibility is to manufacture the container as a prefilled throw away container, in which case no aperture in the top 24a of the container is needed:- the top of the container can be permanently sealed once it has been filled with powder.

If the dispenser is to be made separately from the container and inserted into a container, the insert would provide, as a minimum, wall 13 and metering device 20 secured together by a sufficient framework to keep them in the desired spacing. However, a separate dispenser preferably would include both the walls 13 and 14 as well as the metering device 20.

The above described device is used as follows:- once the container has been filled with powder as shown in Figure 3, with the container standing on its base 24, the metering device 21 allows powder to flow into the area of the container immediately below the open end 19 of the dispensing channel 12.

To dispense a metered amount of powder from the container, the container is tilted, first to the position shown in Figure 4, and then to the position of Figure 5:- in the position of Figure 4, powder starts to flow into the dispensing channel, but as the container is tilted further, to the position of Figure 5, the wall 13 prevents further powder from entering the dispensing channel, and only the amount of powder shown in the crosshatched area 32 in Figure 4 can flow out of the dispensing channel through the open end 19a.

It should be noted that the dispensing position shown in Figure 5 is the normal tipping position for a container, in the sense that it is the approximate angle of tilt which the user normally would use to tip material out of a container; in this position, the container typically is at an angle of between 90° - 160° to the vertical storage position shown in Figure 1 and does not need to be inverted, i.e. the angle of tilt is less than 180° to the storage position. This means that the dispensing device is reasonably foolproof to use:- a user is not required to remember that the container must be inverted beyond the normal tip position or tipped in any particular way or to any particular angle; the dispensing device works correctly if a user simply tips the container in the normal way and then puts the container back in the normal vertical storage position.

As the container is replaced on its base 24, a further amount of powder flows into the area immediately below the open end 19a of the dispensing channel 12, so that the container can be used to dispense metered amounts of powder simply by repeatedly tilting the container.

The fact that the surface 22 is sloped towards the dispensing channel means that powder is directed into the area immediately below the lower end of 19 of the dispensing channel even when there is very little powder in the container. However, the presence of the metering gap b between the sloping surface 22 and the lower edge 25 of the wall 13 ensures that the quantity of powder to be dispensed is correctly metered even if the container is very full:- an excessive amount of powder simply cannot enter the dispensing channel.

The dispenser, and the combination of the dispenser with a container, may be made from any of a large range of materials or combination of materials e.g. cardboard, metal, or plastics materials.

A second embodiment of the invention is shown in Figures 7 and 8. In this embodiment, a container 40 is formed integrally with a dispensing device 41 and the combined container and dispenser are moulded from a suitable impact resistant plastics material.

The container 40 is a moulded plastics container formed with a top filling aperture 42 which is externally screw threaded and can be closed by an internally screw threaded cap (not shown) in known manner. The container 40 also is formed with an integral handle aperture 43.

The dispensing device 41 includes a dispensing channel 44 which is formed between two opposed walls 45, 46; the wall 45 is also an outer wall of the container, and the wall 46 extends across the full width of the container, from the top of the container to a position spaced a short distance above the base 47 of the container.

The width a of the dispensing channel 44 is not completely uniform, because, for ease of manufacture, the upper portion of the wall 46 curves slightly towards the wall 45. However, the width a of the dispensing channel is substantially uniform for a major portion of its length. A metering device 48 is formed integrally with the base 49 of the container. The metering device 48 consists of a triangular cross-section indentation in the base 49 of the container, providing a first surface 50 the plane of which is substantially perpendicular to the plane of the reverse surface 51 .

The first surface 50 extends at an acute angle(typically 45°) to the plane of the base 49 of the container. As with the first described embodiment, the angle x may be varied:- the smaller the angle x, the greater the quantity of powder which will be dispensed in each dispensing cycle. The surface 51 need not be perpendicular to the surface 50, but must be at an acute angle Y to the plane of the base 49 of the container. As with the first embodiment, angles X and Y must be acute, for the reasons discussed with reference to the first embodiment.

The surfaces 50, 51 extend the full width of the container and the edges of the surfaces 50, 51 are formed integrally with the opposite walls of the container.

The lower end of the surface 50 merges with the base 49 of the container a short distance away from the lower end of 52 of the wall 46; this provides a metering gap b between the end 52 and the surface 50; it is the size of this gap b which governs the amount of powder which can pass from the main body of the container into the dispensing channel 44.

The other end of the dispensing channel 44 is formed as an externally screw threaded aperture 53 which may be closed when the container is not in use by a screw threaded cap59.

The embodiment shown in Figures 7 and 8 is used in exactly the same manner as the embodiment described with reference to Figures 1 -6.

As for the first embodiment, the container of Figures 7 and 8 may be fitted with a device for preventing powder from entering the dispensing channel during transport. This is shown in Figure 8 only:- a tube 60 is secured to the cap 59; the tube 60 is a sliding fit within the dispensing channel 44, and the end 61 of the tube 60 is closed off to prevent powder entering the tube. The tube 60 extends nearly to the lower end of the dispensing channel 44, and thus prevents any excess of powder from entering the channel. The tube 60 is removed with the cap 59. Instead of a tube 60, the dispensing channel could be blocked by a circular-cross- section plug, the same shape and position as the end 61 , but mounted on the cap 59 on a stem, rather than on a tube.

For a given size of container, the amount of powder which is dispensed each time the container is tilted can be altered by altering the spacing b between the lower edge 25, 52 of the inner wall of the dispensing channel and the adjacent sloping surface 22, 50 respectively. The spacing b can be altered either by altering the angle x and/or by lengthening or shortening the inner wall of the dispensing channel. In addition, the width a of the dispensing channel must be sufficient that the dispensing channel does not restrict the flow of powder when the dispenser is tipped.

In both the first and second embodiments, the metering device 20, 48 has been described as extending right across the container, i.e. from wall to wall of the container. This certainly is the simplest and most convenient way to form the metering device, but it is of course possible to form the metering device with a lesser width than the container:- the container walls could be indented on each side of the metering device, or the metering device could be formed with baffles at each side, to close off all gaps between the ends of the metering device and the adjacent walls of the container:- the essential point is that the metering device must be arranged within the container in such a way that powder can pass from the container into the dispensing channel only through the metering gap.

The description of use of the dispenser given above envisages that the container would be tilted manually, but it should be appreciated that the container could be tilted mechanically if necessary.