SLACK SEPARATION APPARATUS AND METHOD

Abstract

There are provided hoppers for separating slack from a mixture of product and slack, and systems and method using such hoppers. Each hopper comprises: an internal gate configured to prevent the passage of product therethrough, but to allow the passage of slack therethrough; and, an external gate configured to prevent the passage of product and the passage of slack therethrough; the internal gate and the external gate being moveable between respective open and closed positions; the hopper configured such that: when the internal gate and external gate are in their respective closed positions and the mixture is introduced into the hopper, product is retained by the internal gate whilst slack passes through the internal gate and is retained by the external gate; and, when the external gate and internal gate are each in their respective open positions, product may exit the hopper along a first path.

Claims

1. A hopper for separating slack from a mixture of product and slack, the hopper comprising: an internal gate configured to prevent the passage of product therethrough, but to allow the passage of slack therethrough; and, an external gate configured to prevent the passage of product and the passage of slack therethrough; the internal gate and the external gate being moveable between respective open and closed positions; the hopper configured such that: when the internal gate and external gate are in their respective closed positions and the mixture is introduced into the hopper, product is retained by the internal gate whilst slack passes through the internal gate and is retained by the external gate; and, when the external gate and internal gate are each in their respective open positions, product may exit the hopper along a first path.

2. A hopper according to claim 1, the hopper configured such that when the external gate is in its respective closed position a second path is provided for slack retained by the external gate to exit the hopper, the second path being different from the first path.

3. A hopper according to claim 2, wherein the second path is angled relative to and/or laterally offset from the first path.

4. A hopper according to claim 1, wherein a lower end of the external gate comprises a trough, the trough being configured to receive slack when the external gate is in its respective closed position.

5. A hopper according to claim 4, the hopper being configured such that when the external gate is in its closed position, slack may travel along the trough and exit the hopper along a second path.

6. (canceled)

7. A hopper according to claim 2, wherein the hopper is configured to connect to a vacuum pump configured to collect slack which exits the hopper along the second path.

8. (canceled)

9. A hopper according to claim 1, the hopper configured such that the internal gate is fixed relative to the external gate.

10. A hopper according to claim 1, the hopper configured to move the external gate between its respective closed and open positions independently from the internal gate, such that when the external gate is in its respective open position and the internal gate in its respective closed position, slack may exit the hopper in the first direction whilst product is retained by the internal gate.

11. A hopper according to claim 1, wherein the internal gate comprises one or more apertures, each of the apertures being sized to permit slack to pass therethrough but to prevent the passage of product therethrough.

12. A hopper according to claim 11, wherein the minimum dimension of each of the apertures in the plane of the internal gate is in the range of 0.05 cm to 1 cm.

13. A hopper according to claim 9, wherein the internal gate comprises a filter, mesh, grating, grill, gauze, sieve and/ornet.

14. A hopper according to claim 1, wherein the internal gate is a first internal gate and the external gate is a first external gate; and wherein the hopper further comprises: a second internal gate configured to prevent the passage of product therethrough, but to allow the passage of slack therethrough, and wherein the first and second internal gates are opposed; and, a second external gate configured to prevent the passage of product therethrough and to prevent the passage of slack therethrough, and wherein the first and second external gates are opposed; the second internal gate and the second external gate being moveable between respective open and closed positions; the hopper being configured such that: when the first and second internal gates and first and second external gates are in their respective closed positions and the mixture is introduced into the hopper, product is retained by the first and second internal gates whilst slack passes through the first and second internal gates and is retained by the first and second external gates; and when the first and second internal gates and the first and second external gates are in their respective open positions, product may exit the hopper along the first path.

15. A hopper according to claim 1, wherein the hopper is a weighhopper, pool hopper, booster hopper, timing hopper, output hopper or discharge hopper.

16. A system comprising one or more hoppers according claim 1.

17. A system according to claim 16, the system comprising a vacuum pump connected to a first hopper of the one or more hoppers, the vacuum pump configured to collect slack which exits the first hopper along the second path.

18. (canceled)

19. A system according to claim 16, wherein the system comprises a weighing system wherein the weighing system is a combination weigher, multihead weigher, screw fed weigher, cut gate weigher, linear weigher, or mix weigher.

20. A system according to claim 16, wherein the system comprises a packaging machine, wherein the packaging machine is a bag maker, tray sealer, cartoniser orthermoformer.

21. (canceled)

22. A method for separating slack from a mixture of product and slack, the method comprising: (a) introducing a mixture of product and slack into a hopper, the hopper comprising an internal gate configured to prevent the passage of product therethrough, but to allow the passage of slack therethrough, and an external gate configured to prevent the passage of product and the passage of slack therethrough, the internal gate and the external gate being moveable between respective open and closed positions; wherein the mixture is introduced into the hopper when the internal gate and external gate are in their respective closed positions, such that product is retained by the internal gate, and slack is retained by the external gate; (b) collecting the slack retained by the external gate; and (c) moving the internal gate and external gate into their respective open positions such that product retained by the internal gate exits the hopper via a first path.

23. Amethod according to claim 22, wherein collecting the slack retained by the external gate comprises either: allowing the slack retained by the external gate to exit the hopper by a second path, the second path being different from the first path; or, moving the external gate into its respective open position whilst the internal gate remains in its respective closed position such that slack retained by the external gate exits the hopper via the first path.

24. A method according claim 22, wherein collecting the slack retained by the external gate comprises operating a vacuum pump to collect slack from the hopper.

25. (canceled)

26. (canceled)

27. A method according to claim 22, further comprising the step of transferring the product that exits the hopper via the first path into an item of packaging, and subsequently sealing the item ofpackaging.

28. (canceled)

Description

BRIEF DESCRIPTION OF DRAWINGS

[0091] FIGS. 1a, 1b, 1c show schematic cross sections of a device in accordance with the invention; the figures show sequential arrangements of the device as the device performs of a method in accordance with the invention.

[0092] FIGS. 2a and 2b show schematic cross sections of a further device in accordance with the invention.

[0093] FIG. 3 shows a schematic cross section of a further device in accordance with the invention.

[0094] FIGS. 4a and 4b show perspective views of a further device in accordance with the invention in a closed arrangement and an open arrangement respectively; FIG. 4c shows a cross section through said device in its closed arrangement; FIG. 4d shows a side view of said device in its open arrangement; FIG. 4e shows a further cross section through said device in its closed arrangement.

[0095] FIG. 5 shows, schematically, the preferred position of the device of FIGS. 4a to 4d in a system according to the invention.

DETAILED DESCRIPTION

[0096] FIGS. 1a, 1b and 1c show a hopper 10 suitable for removing slack S from a mixture of product P and slack S. As shown, slack S is a solid particle (e.g. excess sugar) with significantly smaller dimensions than the product P. In more detail, the dimensions of the slack S shown in FIGS. 1a to 1c are approximately an order of magnitude smaller (i.e. 10 times smaller) than the dimensions of the products P. However, the hopper 10 is equally suited for use with mixtures containing liquid slack or solid slack having alternative dimensions relative to the product.

[0097] The hopper 10 comprises an upper opening 11 through which product P and slack S may be introduced into the hopper 10 (as shown in FIG. 1a). The hopper 10 comprises two gates: an internal gate 12; and an external gate 14.

[0098] The internal gate 12 comprises a plurality of apertures 13 which extend through the internal gate 12 (i.e. between the two opposed sides of the internal gate). The apertures 13 are sized such that slack S may pass through the apertures 13 (and therefore through the internal gate 12), but product P may not. Therefore, the internal gate 12 is configured to filter or separate slack S from product P. The dimension of each aperture 13 in the plane of the internal gate 12 is greater than the maximum dimension of the slack S and smaller than the minimum dimension of the product P.

[0099] In contrast the external gate 14 is continuous, and is formed without any apertures. Neither product P nor slack S may pass through the solid external gate 14. The external gate 14 is positioned lower than the internal gate 12 which is positioned within the hopper 10 (i.e. within the internal volume of the hopper 10 defined by the side walls 16a, 16b and the external gate 14), such that slack which passes through the internal gate 12 will be retained by the external gate 14.

[0100] The internal gate 12 is connected to a first side wall 16a of the hopper 10 by a hinge 12a about which the internal gate 12 may rotate. The internal gate 12 may be moved between two positions: a closed position as shown in FIGS. 1a and 1b, where the internal gate 12 extends between the side walls 16a, 16b of the hopper; and an open position as shown in FIG. 1c, where the internal gate 12 hangs from its respective hinge 12a such that there is a gap between a distal or free end of the internal gate 12 and the second side wall 16b of the hopper 10.

[0101] Similarly, the external gate 14 is connected to a first side wall 16a of the hopper 10 by a hinge 14a about which the external gate 14 may rotate. As with the internal gate 12, the external gate 14 may be placed in two positions: a closed position as shown in FIGS. 1a and 1b, where the internal gate 14 extends between the side walls 16a, 16b of the hopper so as to close a lower opening 19 of the hopper 10; and an open position as shown in FIG. 1c, where the external gate 14 hangs from its hinge 14a such that there is a gap between a distal or free end of the external gate 14 and the second side wall 16b of the hopper 10. When the external gate 14 is in its open position (as shown in FIG. 1c) a lower opening 19 of the hopper 10 is opened, such that the contents of the hopper 10 may exit the hopper 10.

[0102] A process for separating slack S from a mixture of product P and slack S will now be discussed with reference to FIGS. 1a, 1b and 1c. These figures illustrate sequential steps performed using the hopper 10.

[0103] Firstly a mixture of product P and slack S is introduced into the hopper 10 whilst the internal gate 12 and the external gate 14 are in their respective closed positions (as shown in FIG. 1a).

[0104] Having entered the hopper 10, the product P and slack S encounter the internal gate 12. Slack S may pass through the apertures 13 in this internal gate 12, whereas product P may not. Therefore, the product P is retained by the internal gate 12, whereas a proportion of (and preferably substantially all of) the slack S contained in the hopper 10 travels through the internal gate 12. The slack S which passes through the internal gate 12 falls to the lower external gate 14. Hence, the slack S which travels past the internal gate 12 is retained or caught by the underlying external gate 14. The resulting arrangement is shown in FIG. 1b.

[0105] From FIG. 1b it will be seen that small amounts of slack S may remain with the product P retained by the internal gate 12. In many cases it will be preferable to remove large proportions of slack S from a mixture of product P and slack S (e.g. at least 75% of slack or at least 90% of slack). However, in practice it is difficult and/or unnecessary to separate all slack S from product P.

[0106] It will be appreciated that the proportion of slack S removed from a mixture using the hopper be controlled by (for instance): varying the length of time the mixture spends in the hopper 10 (i.e. the dwell time of product P); and the size and distribution of apertures in the internal gate 12; and the dimensions of the hopper 10. These parameters may be varied to change the proportion of slack S which is removed from a given mixture of slack S and product P.

[0107] Once slack S has been separated from the product P by the internal gate 12, the separated slack S is allowed to exit the hopper 10. The slack S may be automatically or manually collected, and may be reintroduced into the production line upstream of the hopper 10 so as to reduce waste. For instance, the separated slack S retained by the external gate 14 may be removed from the hopper 10 by operating a vacuum pump (not shown), and/or by opening the external gate 14 whilst keeping the internal gate 12 closed to discharge only the separated slack S through the lower opening 19 of the hopper (although other techniques may also be used).

[0108] Subsequently, the product P retained by the internal gate 12 may be discharged or dispensed by the hopper 10, as shown in FIG. 1c. The remaining contents of the hopper 10 are released by opening the internal gate 12 and the external gate 14 at the same time - i.e. by moving the internal gate and the external gate into their respective open positions. FIG. 1c demonstrates this step, showing product P passing through the lower opening 19 of the hopper 10.

[0109] Thus the product P (and any remaining slack S) exits the hopper 10 along a first path that extends through the lower opening 19 of the hopper 10. It will be seen that the product mixture discharged by the hopper 10 in FIG. 1c has significantly less slack S than the product mixture introduced into the hopper 10 in FIG. 1a.

[0110] This process may be repeated by returning the internal gate 12 and the external gate 14 to their respective closed positions (shown in FIG. 1a) and refiling the hopper 10 with a fresh mixture of product P and slackS.

[0111] A delay may be provided between closing the internal and external gates 12, 14 and re-opening the internal and external gates 12, 14. This delay may allow the mixture of product P and slack S to enter the hopper 10, and enables the slack S to be separated and to be collected from the hopper 10. Additionally, the delay may allow the remaining contents of the hopper 10 to settle, and the weight of the contents of the hopper to stabilise. The delay may be, for example, 400 ms or 800 ms.

[0112] Additionally, or alternatively, the weight of the contents of the hopper 10 may be periodically or continuously monitored so that the opening of the gates 12, 14 of the hopper 10 is performed once the weight of the hopper 10 has stabilised (indicating that the contents of the hopper 10 have settled and excess slack S has been removed), but not before. For example, weight measurements can be taken of the contents of the hopper 10 on a periodic basis, for example once every 10 ms. The weight of the contents of the hopper 10 could be determined to have stabilised if three consecutive measurements are of the same value, or are within a predetermined range of, for example, 0.15 g.

[0113] The product P discharged by the hopper 10 may subsequently be transferred or fed into an item of packaging (e.g. a bag, tray, or carton). The method may further comprise the step of sealing the item of packaging (e.g. using a bag maker, tray sealer, cartoniser or thermoformer).

[0114] FIGS. 2a and 2b show a modified version of the hopper 10 of FIGS. 1a, 1b and 1c. This modified hopper 10 is again suitable for separating slack S from product P using the methods described above and shares many features and benefits with the hopper 10 shown in FIGS. 1a, 1b and 1c. Corresponding features of the two hoppers 10, 10´ are indicated by reference signs with the prime symbol.

[0115] The hopper 10´ of FIGS. 2a and 2b comprises two side walls 16a´, 16b´ between which is defined an upper opening 11´ through which product and slack may be introduced into the hopper 10´. The hopper 10´ comprises an internal gate 12´ and an external gate 14´, the external gate 14´ being positioned below the internal gate 12´ (as shown).

[0116] The internal gate 12´ comprises a plurality of apertures 13´, the apertures 13´ being sized so that slack but not product may pass through the internal gate 12´. Therefore the internal gate 12´ may filter slack out of a mixture of product and slack. In contrast, the external gate 14´ is continuous, being formed without gaps or apertures, so that slack may not pass through the external gate 14´.

[0117] The internal gate 12´ and external gate 14´ may rotate about respective hinges 12a´, 14a´ connected to a first side wall 16a´ of the hopper 10´. Therefore, the internal gate 12´ and external gate 14´ may be moved between respective open and closed positions.

[0118] FIG. 2b shows the internal gate 12´ and the external gate 14´ in their respective open positions. In this arrangement a lower opening 19´ of the hopper 10´ is defined. The contents of the hopper 10´ may exit the hopper 10´ along a first path extending through this lower opening 19´, as indicated by arrow R.sub.1.

[0119] Unlike the preceding example, the hopper 10´ of FIGS. 2a and 2b comprises a slack collection duct 17 provided in the second side wall 16b´ of the hopper 10´. This slack collection duct 17 may be used to collect slack that has passed through the internal gate 12´ and been retained by the external gate 14´.

[0120] Therefore, slack may exit the hopper 10´ along a second path (indicated by arrow R.sub.2) that is different to the first path, the second path extending through the slack collection duct 17. As will be seen from the Figures, the second path is laterally offset and angled from the first path.

[0121] The hopper 10´ is configured such that the slack collection duct 17 is located at the lower end of the second wall 16b´. Moreover, the external gate 14´ is angled relative to the horizontal and slopes towards the slack collection duct 17 when the external gate 14´ its closed position (as shown in FIG. 2a). Therefore, slack which reaches the closed external gate 14´ may flow towards the slack collection duct 17 and out of the hopper 10´ along the second path.

[0122] A vacuum pump (not shown) may be connected to the slack collection duct 17 (e.g. via a flexible tube) to pull slack from the hopper 10´. However, in alternative examples slack may flow down the second path R.sub.2 and through the slack collection duct 17 under gravity and without assistance.

[0123] FIG. 3 shows a further hopper 20 comprising a “double door” arrangement. This hopper 20 is well suited for use with sticky products which might adhere to the side walls and gates of “single door” hoppers (such as hoppers 10, 10´ shown in FIGS. 1 and 2).

[0124] The hopper 20 comprises an upper opening 21 is defined between a pair of side walls 26a, 26b. Between the side walls are provided a pair of opposed internal gates 22, and a pair of opposed external gates 24 (each shown in a respective closed position in FIG. 3). Each internal gate 22 comprises a plurality of apertures 23 through which slack, but not product, may pass. Each internal gate 22 and each external gate 24 may rotate between a respective closed position and a respective open position about their respective hinge 22a, 24a.

[0125] The internal gates 22 and external gates 24 are shown in their respective closed positions in FIG. 3. As will be seen, the internal gates 22 project from their respective side walls 26a, 26b such that the free ends of the internal gates 22 meet at a centre of the hopper 20. Similarly, the external gates 24 project from the side walls 26a, 26b of the hopper 20 such that their free ends meet at a centre of the hopper 20.

[0126] In this arrangement slack may be filtered from a mixture of product and slack introduced into the hopper 20. Slack introduced into the internal volume of the hopper 20 may pass through the apertures 23 within the internal gates 22, whereas product may not. This separated slack will subsequently be retained by the underlying external gate 24 which is of a continuous sheet without apertures.

[0127] The separated slack may subsequently be removed from the hopper 20 and collected. For instance, the separated slack may be removed from the hopper 20 manually, by opening only the external gates 24 or by operating a vacuum pump (not shown). In further examples a slack collection duct or an aperture in the walls of the hopper 20 may be provided through which slack may exit the hopper 20.

[0128] Subsequently, the product remaining in the hopper 20 may be discharged from the hopper 20 by moving the internal gates 22 and external gates 24 to their respective open positions. Hence the hopper 20 may be used to discharge a product mixture with reduced levels of slack - i.e. a mixture from which slack has been removed.

[0129] It will be appreciated that the hoppers 10´, 20 shown in FIGS. 2 and 3 may comprise any of the preferable or optional features discussed in relation to the hopper 10 shown in FIG. 1 (and vice versa). Equally, the hoppers 10´, 20 of FIGS. 2 and 3 may perform corresponding process steps to those described in relation to the hopper 10 of FIG. 1.

[0130] A further hopper 30 with “double doors” that is suitable for separating slack from a mixture of product and slack is shown in FIGS. 4a to 4e.

[0131] The hopper 30 comprises a pair of opposed external gates 34. The external gates 34 may each rotate relative to the side walls 36 of the hopper 30 between a respective closed position (shown in FIGS. 4a, 4c and 4e) and a respective open position (shown in FIGS. 4b and 4d). When each external gate 34 is in its respective closed position the free ends of the external gates 34 meet or abut at the centre of the hopper 30, closing a lower opening 39 of the hopper 30. Whereas, when each external gate 34 is in its open position the external gates 34 are laterally offset or spaced apart, and a lower opening 39 extends between the external gates 34.

[0132] The rotation of each external gate 34 is controlled using a respective lever arm 34b. Each lever arm 34b is fixed to the corresponding external gate 34, and rotatably coupled to the side walls 36 of the hopper 30 by a hinge (not shown) that extends through holes 34c in the lever arm 34b and the side walls 36 of the hopper 30.

[0133] The hopper 30 further comprises a pair of oppo sed internal gates 32. Each internal gate 32 is fixedly coupled to a corresponding external gate 34 by coupling portions 35 (as seen most clearly in FIG. 4c). Each internal gate 32 extends parallel to the external gate 34 to which it is attached (although this is not essential). The connection between the corresponding internal and external gates 32, 34 may be permanent (e.g. the gates 32, 34 may be welded or bonded together using adhesive) or non-permanent (e.g. using threaded fasteners such as screws).

[0134] As the internal gates 32 are fixed relative to the external gates 34, each internal gate 32 will rotate with the external gate 34 to which they are attached. Therefore, each internal gate 32 may be moved between a respective open position and a respective closed position by moving the corresponding external gate 34 between its respective open and closed positions.

[0135] When the internal gates 32 are in their respective closed positions, the internal gates 32 meet at the centre of the hopper 34. Each internal gate 32 comprises an array of apertures 33 which extend through the internal gate 32. The apertures 33 are sized such that a relatively large product may not pass through the internal gate 32, whereas the relatively small or liquid slack may travel through the internal gate 32. Therefore, the internal gates 32 may act as filters, separating product from slack when each internal gate 32 is in its respective closed position.

[0136] As shown, each internal gate 32 comprises a repeating array of oval apertures 32. However, it will be appreciated that apertures with a wide variety of sizes and arrangements may be selected for use in the hopper 30, depending on the mixture of product and slack in question.

[0137] When the internal gates 32 and external gates 34 are placed in their closed positions (as shown in FIG. 4c, which is a cross section along line E-E of FIG. 4e) and a mixture of product and slack is introduced into the hopper 30, product will be retained by the internal gates 32 whereas slack may pass through the internal gates 32 and fall to the underlying external gates 34.

[0138] Each of the external gates 34 further comprises a trough 38 (most easily seen in FIG. 4c). The troughs 38 are open channels or a duct which may receive slack which has passed through the overlying internal gates 32. In particular, the hopper 30 is configured such that, when the internal and external gates 32, 34 are in their respective closed positions, slack which has passed through the internal gates 32 may fall to the external gates 34 and accumulate in the troughs 38.

[0139] When the external gates 34 are in their respective closed positions, the external gates 34 are angled towards their respective troughs 38. Indeed, when each external gate 34 is in its closed position, the external gate 34 is angled downwards from an end proximal to the respective hinge and lever arm 34b towards a free end which comprises the trough 38. Since each external gate 34 is angled towards its respective trough 38 when the external gate 34 is in its respective closed position, slack which passes through the internal gates 32 and subsequently reaches the external gates 34 may fall or flow along the surface of the external gates 34 into the troughs 38 (e.g. under gravity).

[0140] The base 38a of each trough 38 is angled relative to the horizontal, such that the depth of the trough 38 increases along the length of the trough 38. Therefore, slack which accumulates in the trough 38 may flow or travel laterally along the base 38a of the trough 38 (e.g. undergravity).

[0141] The hopper 30 further comprises a slack collection duct 37 connected to each external gate 34 at its lower edge. More specifically, each slack collection duct 37 connects to the lower end of a corresponding trough 38. Therefore, slack which passes through the internal gates 32 and falls to the external gates 34 will flow or drain along the angled surface of the external gates 34 into the troughs 38, and will subsequently flow or drain to the slack collection duct along the angled base 38a of each trough 38. Thus each trough 38 and the corresponding slack collection duct 37 communicate, and slack may exit the hopper 30 along a path (i.e. a second path) that extends from each trough through the corresponding slack collection duct 37. This path is offset and angled relative to the substantially vertical path (i.e. a first path) that the contents of the hopper 30 will take through the lower opening 39 of the hopper when the internal and external gates 32, 34 are moved to their respective open positions.

[0142] The passage of slack out of the hopper 30 via the slack collection duct 37 may occur under gravity, by vibrating the hopper and/or slack collection duct 37, and/or by applying a suction force by connecting a vacuum pump (not shown) to the slack collection duct 37.

[0143] The slack connection duct 37 may be connected to a flexible tube (not shown), although as described above a rigid tube may also be used. A flexible tube may accommodate change in the position of the slack removal duct 37 as the external gate 34 of the hopper 30 is opened and closed. For instance, a vacuum pump may be connected to the slack connection duct 37 via a flexible tube. However, this is not essential and in further examples the slack removal duct 37 may itself be formed of a flexible material and/or may directly connect to a vacuum pump or reservoir. In these cases slack may continue to travel along the second path which continues through the flexible tube.

[0144] It will be appreciated that in the example shown in FIGS. 4a to 4e, slack may flow from the troughs 38 into the slack collection ducts 37 and therefore exit the hopper when the external gates 34 are in their respective closed position and in their respective open position. Therefore, excess slack may continue draining from the hopper 30 without delaying the hopper 30 from discharging its remaining contents.

[0145] Thus, once a mixture of product and slack has been introduced to the hopper 30, slack will be separated from the product by the internal gates 32. The separated slack will accumulate in the troughs 38 of the external gates and will exit the hopper for collection through the slack collection ducts 37. Subsequently the remaining contents of the hopper may be discharged through the lower opening 39 of the hopper 30 by opening the internal and external gates 32, 34.

[0146] The contents of the hopper may only be discharged once the contents of the hopper 30 have had an opportunity to settle. For instance, the internal and external gates 32, 34 of the hopper 30 may only be opened after a predetermined delay has elapsed (e.g. 400 ms, 800 ms or 1000 ms) or when the weight of the contents of the hopper has stabilised (e.g. when the weight measurement(s) from the hopper are constant or fall within a predetermined tolerance).

[0147] The discharged product with reduced levels of slack dispensed by the hopper 30 may subsequently be packaged using a packaging apparatus and/or continue to be handled and/or modified by subsequent machinery. This subsequent packaging and product handling operations will be more reliable and of higher quality thanks to the reduced levels of slack.

[0148] Any of the hoppers discussed above may be installed in wider product handling system.

[0149] For instance, the hoppers may be provided as part of a weighing system and used to accurately discharge known quantities of product with reduced levels of slack. The product handling system may further comprise a packaging apparatus to package the discharged product. Alternatively, the product may continue along a production line and be further modified by subsequent machinery. The subsequent packaging and product handling operations may be more reliable and provide packaged articles of higher quality thanks to the reduced levels of slack dispensed by the hoppers discussed above.

[0150] A preferred example of the hopper of FIGS. 4a to 4d installed in a system according to the invention will now be described with reference to FIG. 5.

[0151] FIG. 5 shows, schematically, the hopper 30, described above, installed in a system 100 that forms batches of product having a predetermined weight and provides these fixed-weight batches to a packaging machine.

[0152] The system 100 comprises a combination weigher 200 located upstream of the hopper 30. An example of a suitable combination weigher would be the RV-Series Multihead Weigher sold by Ishida Europe Limited of 11 Kettles Wood Drive, Woodgate Business Park, Birmingham. B32 3DB.

[0153] Generally, a combination weigher comprises a series of weigh hoppers 210, only two of which are visible in FIG. 5, arranged in a circle about a central axis. Each weigh hopper is fed by a supply, e.g. a product dispersion table, to receive an amount of product. The weights of product in each hopper are continuously monitored and the combination weigher selects any two or more hoppers whose total weight satisfies criteria relating to the weight of a batch of product to be formed and dispenses the product from those hoppers, bringing the product together into a single batch of product having the desired weight. In the present example, the combination weigher 200 is shown as having a funnel 220 that encompasses all of the weigh hoppers 210 for bringing together product dispensed by any two or more weigh hoppers 210 and depositing the productin the slack-separating hopper 30. It should be noted that each weigh hopper 210 could also be formed as a slack-separating hopper according to the invention, although this is not essential.

[0154] The slack-separating hopper 30 is thereby provided with a mixture of product and slack whose weight satisfies the predetermined weight criteria for a batch of product. Slack is removed from the hopper 30 by the mechanism described above and this will typically have a negligible effect on the weight of the batch of product. In a case where a significant amount of slack is removed at the hopper 30, it will typically be possible to adjust for this in the combination weigher 200 by forming batches that are overweight by a predetermined amount to compensate for anticipated weight loss as slack is removed. Having received a batch of product, the hopper 30 then dispenses the batch of product into a packaging machine 300 located downstream.

[0155] Only a portion of a packaging machine 300 is shown schematically in FIG. 5. An example of a suitable packaging machine for use in the present system would be the Astro Bagmaker sold by Ishida Europe Limited of 11 Kettles Wood Drive, Woodgate Business Park, Birmingham. B32 3DB.

[0156] The packaging machine 300 includes a former 310 which forms a supply film into a cylinder, which cylinder of film is sealed at intervals by a sealer (not shown) to form individual bags. The former 310 comprises an inner forming tube 311 and an outer forming collar 312, which together shape the supply film into a cylinder. The packaging machine also comprises a funnel 320 that connects into the upper opening of the inner forming tube 311 and which feeds product into bags as they are being formed.

[0157] In the present system, the hopper 30, having received the product from the weigher 200 and separated out the slack, dispenses the batch of product along the first path, which in this case involves the product falling vertically under gravity as the hopper opens, into the funnel 320 of the packaging machine 300, where it is received in a package, i.e. in a bag as it is formed by the packaging machine. The product will typically be dispensed by the hopper 30 once the lower seal of a bag has been made and once the product is received in the bag an upper seal will be made to seal the bag, which upper seal will thereby form the lower seal of the next bag so that the process can be repeated.

[0158] The timing of the hopper 30 opening to dispense product into the packaging machine will typically be controlled by a system controller (not shown) that controls together the weigher 200, the hopper 30 and the packaging machine 300 of the system 100. Typically the system will operate a full cycle in between 100 to 1000 ms and most typically about 500 ms. That is, batches of product will be dispensed by the hopper 30 at regular intervals of approximately 500 ms in order to match the production rate of packages by the packaging machine 300.

[0159] While the above system shows the hopper 30 integrated between a weigher 200 and a packaging machine 300, it will be appreciated that this hopper 30 is suitable for use anywhere along the production of a mixture of product and slack. For example, as mentioned, the hoppers could be integrated into the weigher 200, or could be integrated as part of the supply to the weigher 200.