Slack separation apparatus and method

Abstract

Hoppers for separating slack from a mixture of product and slack, and systems and methods using such hoppers, each including an inner gate configured to block product but not slack, and an outer gate configured to block product and slack, the inner and outer gates being movable between respective open and closed positions, such that when the inner and outer gates are in their respective closed positions and a mixture is introduced into the hopper, the product is retained by the inner gate, but the slack passes through the inner gate and is retained by the outer gate, and when the outer and inner gates are in their respective open positions, the product leaves the hopper along a first path.

Description

[Technical field]

[0001] The present disclosure relates to an apparatus, system and method for separating excess slack from a product stream that includes a mixture of product and slack. For example, the slack may be a food coating such as sugar in a confectionery product, crumbs in a breaded product, or seasoning for a seasoned snack.

[0002] More particularly, aspects of the present invention relate to an improved hopper design and systems and methods that utilize the same. The apparatus and methods according to the present invention are particularly suited for use in the food packaging industry. [Background technology]

[0003] Some products are packaged with additional ingredients, referred to herein as "slack." Slack is generally in a generally solid or liquid form and may be mixed with a solid product before the mixture is portioned and packaged. When the slack is generally solid, its dimensions are significantly smaller than those of the product itself, often at least 5 times smaller and more commonly at least an order of magnitude smaller (i.e., 10 times smaller) than the dimensions of the product. For example, the slack may be in the form of a powder or particles.

[0004] Slack may be included in product packaging to protect the product in some way, for example protecting the product from deterioration due to exposure to certain chemicals or from movement of the product within the packaging. Alternatively or additionally, slack may be included to improve the product in some way, for example sugar, crumbs or herbs may be provided to provide a light coating to a food product to improve taste, texture and / or appearance. Alternatively or additionally, slack may arise during processing of the product prior to packaging, for example a product such as a potato chip or crisp may crumble or break to form fragmented slack.

[0005] Additionally, in some processes (e.g., coating processes) it may be necessary to mix the product with slack in a manner that results in a higher percentage of slack to product than is required in the final packaged product, to ensure a uniform coating, etc. However, this raises the question of how to separate the excess slack from the product prior to packaging.

[0006] However, for some products, it is not desirable to have excess slack floating freely in the packaging. For example, if excess crumbs are floating in the packaging of a breaded food intended for oven cooking, the excess slack may bake onto the oven tray. Separating the excess slack before packaging helps to solve these problems.

[0007] An additional problem can occur when the product and slack mixture is allowed to fall into a package that is then sealed towards the top. If the slack falls at a slower rate than the product, such as when the product is a jelly confection and the slack is a sugar coating, the seal quality may be compromised by the slack (sugar) trapped in the seal. This can be avoided by delaying the sealing process to allow the slack to sink to the bottom before sealing, but this method slows down the process and reduces the production of packaged product.

[0008] Excess slack can also accumulate or stick to machinery that processes the product, which can cause the machinery to malfunction and, in the case of food-producing machinery, can pose a public health problem if slack remains trapped in the machinery for an extended period of time, causing spoilage or attracting pests.

[0009] Therefore, there is a need for an alternative method and / or apparatus for separating excess slack from a product stream, preferably one that contributes to solving one or more of the problems set forth above. Summary of the Invention

[0010] The present invention provides an improved apparatus, system, and method for removing slack from a product stream. Specifically, the apparatus and system according to the present invention include a hopper that can be used to store, meter, and discharge a product, and the degree of slack is reduced. For example, when used in the food industry, the present invention is suitable for separating the powdery sugar from confectionery, separating the extra flavorings and fragments from crisps and chips, separating the breadcrumbs from breadcrumb-coated products, and separating the extra marinade from raw meat products (but not limited to these).

[0011] As used herein, "slack" is to be understood to include solids having dimensions significantly smaller than the dimensions of the products (e.g., foods) within the liquid and / or product stream. Thus, the solid portion within the solid slack or slack containing both liquid and solid can be separated from or distinguished from the product based on size. For example, the solid slack is in the form of powder or particles, while the product is significantly larger. The solid slack has dimensions at least 5 times, more typically 10 times smaller than the dimensions of the product within the mixture of product and slack.

[0012] According to one aspect of the present invention, there is provided a hopper for separating slack from a mixture of product and slack, the hopper comprising an internal gate configured to allow slack to pass through but not the product, and an external gate configured to prevent the product and slack from passing through, the internal gate and the external gate being movable between their respective open and closed positions, and when the internal gate and the external gate are in their respective closed positions and the mixture is introduced into the hopper, the product is held by the internal gate while the slack passes through the internal gate and is held by the external gate, and when the external gate and the internal gate are in their respective open positions, the hopper is configured such that the product exits the hopper along a first path.

[0013] By removing excess slack from the product stream using such an apparatus, the reliability of the product processing system can be enhanced and the quality of the final product can be improved.

[0014] It will further be appreciated that the present invention provides a particularly fast and efficient means of removing slack from a product stream. Hopper according to the present invention is particularly space efficient since an element (i.e., an internal gate) that divides or separates the slack from the product is provided inside the hopper. Moreover, hoppers according to the present invention can be easily retrofitted to product processing machines to replace existing hoppers that are not suitable for separating slack from a product stream.

[0015] Furthermore, slack can be removed from the product stream while the product is settling in the hopper without significantly slowing the discharge of the product from the hopper, and therefore without significantly impacting the hopper's throughput and / or the output of the broader system.

[0016] The hopper separates slack from product when the inner and outer gates are each in a closed position, i.e., when the inner gate is in a closed position and the outer gate is also in a closed position. When the hopper is in this configuration, product introduced into the hopper is retained (i.e., held in place or captured) by the closed inner gate, while at least a portion of the slack passes through the closed inner gate (e.g., under gravity). Thus, the product captured by the inner gate is separated or divided from the slack that passed through the inner gate.

[0017] Slack that passes through the closed inner gate is then retained or captured by a closed outer gate located below the inner gate. The separated slack is then collected or dumped and collected separately from the product. Collection of the slack may be manual (i.e., by hand) or may be automated by equipment and / or a wider system. Excess slack separated and collected using the equipment may be reintroduced and reused in the production line upstream of the equipment to reduce waste.

[0018] The product held by the closed inner gate (and any remaining slack) is then discharged, i.e., exits the hopper, by opening the inner and outer gates, i.e., by moving the inner and outer gates to their respective open positions.

[0019] The amount of slack removed by the hopper from the mixture of product and slack may depend on the length of time the mixture resides in the hopper (i.e., the "residence time" of the product in the hopper). Similarly, the percentage of slack removed by the hopper may depend on the particular product and slack involved. For example, in preferred implementations, at least 15%, more preferably 25%, even more preferably 50%, and even more preferably 75% of the slack is removed from the mixture introduced into the hopper.

[0020] It is particularly beneficial to remove slack from the product and slack mixture at the hopper as compared to other stages of the production line, since the product may fall or drop significantly into the hopper (e.g., from a product supplying device such as a dispersion feeder, screw feeder, conveyor or other suitable machine). Such a fall may result in a significant amount of slack being created as the product bumps or collides against the hopper. Thus, the device according to the present invention can quickly remove the slack after it is formed and before it is transferred to a downstream product processing machine or before the product is dispensed into a package of a packaging machine. In particular, it is desirable to provide a slack removal hopper as the final hopper before the food product is dispensed into a package of a packaging machine, since slack is typically created whenever the product bumps or collides against a surface such as the inside of a hopper. A single slack removal hopper provided as the final hopper before packaging can act to remove all slack at the last moment when a large amount of slack is created, minimizing the amount of slack in the final packaged product. For example, a slack removal hopper may distribute product along a first path that leads directly or indirectly to a package of a packaging machine, for example, the product may drop directly from the hopper into the package or may be conveyed along one or more funnels or chutes into the package.

[0021] The inner and / or outer gates may move between their respective open and closed positions by rotation about a hinge (e.g., a corresponding hinge), or the gates may slide between their respective open and closed positions.

[0022] Preferably, the hopper is configured such that a second path, different from the first path, is provided for the exit of slack held by the external gate from the hopper when the external gate is in a closed position. In this way, the slack separated from the product by the internal gate is removed or collected from the hopper via the second path (e.g., via an opening or a slack collection duct defined by the hopper). This removal or collection may be automatic, i.e. without human intervention. Because the second path is different from the first path, the slack does not re-enter the product stream and does not interfere with downstream product processing equipment. Thus, the reliability of the system including the hopper and the quality of the product output by the system can be improved.

[0023] For example, the hopper may be configured to allow slack exiting the hopper along a second path to enter a receiving reservoir (or other container) that may be periodically or continuously emptied as needed (e.g., to reintroduce the slack into the product line upstream of the hopper).

[0024] In some embodiments, the second path may be angled and / or laterally offset relative to the first path. By "angled," it is meant that the second path is angled from the first path and extends in a direction that is not parallel to the direction in which the first path extends. However, in other examples, the separated slack may be discharged or collected from the hopper along the same path as the product (i.e., along the first path), as described further below.

[0025] Preferably, the outer gate includes a trough at its lower end, which is configured to receive slack when the outer gate is in a closed position. For example, slack separated from the product by the inner gate falls by gravity into the outer gate and accumulates or collects in the trough. Having a trough (e.g., a groove or slot) formed in or on the outer gate facilitates collection and removal of the slack.

[0026] Additionally, the recess prevents slack from being unintentionally pushed out of the hopper when the outer gate moves from the open position to the closed position (and vice versa), and thus a hopper having such a recess can be incorporated into an effective and reliable system for preventing slack from passing to other product processing machinery.

[0027] Preferably, the hopper is configured such that when the external gate is in the closed position, the slack travels along the recess and exits the hopper along a second path. For example, the second path may extend through an opening or gap in a side wall of the hopper adjacent the recess or through a duct or tube extending from the hopper when the external gate is in the closed position. In a further preferred example, the apparatus may be configured such that the slack can travel along the recess and exit the hopper (e.g., under gravity or suction) when the external gate is in either the open or closed position.

[0028] In some examples, the bottom of the cavity may be angled so that the slack moves along the bottom of the cavity under gravity. It will thus be understood that the bottom of the cavity is not parallel to either a horizontal or vertical axis in use. Thus, slack (particularly slack in liquid or particulate form) flows along the bottom of the cavity and exits the hopper along a second path. This slack can be readily collected at the lower end of the cavity or continues to exit the hopper along the second path (e.g. through a gap or opening in the hopper, or through a slack collection duct defined by the hopper). However, in further examples, the cavity may have a bottom that does not have an angle. That is, the hopper may have a cavity with a bottom that extends in a generally horizontal direction in use.

[0029] Additionally or alternatively, the hopper may be configured to be connected to a vacuum pump configured to collect slack exiting the hopper along the second path, such that excess slack separated from the product at the inner gate and retained by the outer gate may be quickly and easily removed from the hopper. For example, the hopper may be configured such that suction from the vacuum pump is applied to or near the outer gate when the gate is in at least a closed position to collect slack retained by the outer gate.

[0030] In a preferred configuration, the vacuum pump may be configured to connect to a recess formed at the bottom of the external gate as described above. In these embodiments, under the suction force of the vacuum pump, the slack moves along the bottom of the recess and out of the hopper. That is, the vacuum pump draws the slack along the recess and the slack exits the hopper along the second path. Preferably, the vacuum pump is connected to the bottom of a recess having an angled bottom so that the slack flowing or moving along the bottom of the recess can be easily collected and transported elsewhere (e.g., reintroduced into an upstream production line).

[0031] Alternatively or additionally, the hopper may be configured so that the separated slack is manually collected or flows from the hopper by gravity. In a further example, the hopper may be configured to keep the inner gate closed and move the outer gate to an open position so that the separated slack can be discharged from the hopper while the product is retained by the inner gate.

[0032] Preferably, the hopper is configured to connect to a tube, and the hopper is configured such that the second passage extends through the tube. Here, the term "tube" refers to a conduit of any shape for conveying the slack from the hopper, but typically the tube is cylindrical in cross section. The tube may be rigid or flexible as required. A "rigid" tube is one that does not substantially deform under the forces associated with use, whereas a "flexible" tube may deform or bend under the forces. Rigid tubes are made of materials such as metal or hard plastic, are relatively easy to clean, and typically have a long lifespan. Flexible tubes, on the other hand, are able to accommodate significant vibration or movement of the hopper components without breaking or becoming detached from the hopper. Flexible tubes are made of natural or synthetic rubber (e.g., silicone) or any other suitable material. The tube may be permanently connected to the hopper, but in preferred embodiments may be removable or selectively separable (e.g., for maintenance or cleaning).

[0033] In a preferred embodiment, the tube is configured to connect to the external gate. If the tube is flexible, the upstream end of the flexible tube moves with the external gate as it moves between the open and closed positions, and the downstream end is connected to a fixed duct through which the slack is transported. If the tube is rigid, the entire tube moves with the external gate as it moves between the open and closed positions, and a duct with an opening that coincides with the path traveled by the rigid tube is arranged so that all slack passing through the rigid tube is received by the duct. In an embodiment in which the hopper includes a recess formed at the lower end of the external gate, the tube may be configured to connect to the recess or to communicate with the recess. Thus, the slack separated by the internal gate and held by the external gate moves or flows along the recess and enters the tube for removal. In a particularly preferred embodiment, the slack received in the recess can be removed from the hopper in this way, regardless of whether the external gate is in the open or closed position. This allows slack to be removed from the hopper more effectively without slowing down the operation of the hopper (i.e., the discharge of product by the hopper).

[0034] Additionally or alternatively, the hopper may be configured to connect to a vacuum pump via a tube, i.e., the tube may be configured to connect to the hopper at a first end and to the vacuum pump at a second end such that suction from the vacuum pump is applied to the hopper via the tube and slack separated at the internal gate is collected along a second path extending through the tube.

[0035] The tube may be integrally formed with the hopper and / or may be permanently connected (e.g., by adhesive) to the hopper, although in a preferred example the hopper is configured to removably connect to the tube, allowing the tube to be removed, for example for cleaning or maintenance.

[0036] For example, the hopper may include a rigid slack collection duct through which the hopper is connected to the tube. Thus, the hopper may be configured such that the tube can be inserted into the slack connection duct and / or the slack connection duct can be inserted into the flexible tube. Thus, the tube can be easily and quickly connected to the hopper by simply pushing the tube over or into the end of the rigid slack connection duct.

[0037] The slack connection duct thus allows the slack to be transferred from the hopper to the tube. The slack leaves the hopper along a second path through both the rigid slack connection duct and the tube. The slack connection duct may be formed as a tube or an open channel, but is not limited to these forms. Alternatively, other means may be provided for connecting the tube to the hopper.

[0038] In yet another example, the hopper may include a rigid slack collection duct that allows the separated slack to be discharged from the hopper and collected without the need for ducts to direct the slack away from the hopper, for example, the slack collection duct may feed the separated slack directly into a receiving reservoir.

[0039] In the above example where the slack is discharged from the hopper via the second path, the inner and outer gates may be configured to move simultaneously (e.g., in tandem) between their respective open and closed positions. For example, the hopper may be configured such that the inner gate is secured to the outer gate. In such an embodiment, the inner and outer gates, which are rigidly connected (e.g., by screws, adhesive, or welding), move simultaneously in tandem.

[0040] However, this is not required, and in a further example, the hopper may be configured such that the positions of the inner and outer gates are separately controlled (so that the outer and inner gates are opened and closed independently), i.e., the inner and outer gates may each be separately coupled.

[0041] The hopper may be configured to move the outer gate between the closed and open positions independently of the inner gate such that when the outer gate is in the open position and the inner gate is in the closed position, product is retained by the inner gate and slack exits the hopper in a first direction. Thus, excess slack separated from product by the inner gate is discharged separately (i.e., at a different time) from product by opening the outer gate without opening the inner gate.

[0042] In such an embodiment, the hopper may be configured to alternately discharge product and excess slack along a first path, i.e., excess slack separated from product by an internal gate of the hopper exits the hopper at a different time than the product, rather than along a different path than the product.

[0043] Additional machinery or components may be used to collect the slack traveling along the first path. For example, a vacuum pump may be configured to collect the separated slack as it is discharged from the hopper along the first path. Additionally or alternatively, the first path may pass across or over a filter, mesh, grate, grill, or net with a plurality of openings (e.g., in a regular or irregular array). These openings may be sized to allow the slack to pass but not the product. Thus, once the product and slack have passed through the filter, the product continues to travel along the first path, but the slack is separated and diverted along a path separate from the product.

[0044] In further embodiments, the apparatus may be switchable (i.e., configured to be switchable) between two different modes, where in a first mode the outer and inner gates move together and in a second mode the outer and inner gates move independently. Thus, the hopper may be configured to discharge excess slack along either the first path or the second path.

[0045] In a preferred embodiment, the internal gate comprises one or more openings, each of which is sized to allow slack to pass through but not product. Thus, slack can pass through the openings (i.e. holes or perforations extending entirely through the internal gate) but product cannot. Thus, product is retained by the internal gate but slack is not. Additionally or alternatively, the hopper may be configured such that a gap or opening is formed between the internal gate and a fixed wall of the hopper, allowing slack to pass through the gap or opening but not product.

[0046] It will be appreciated that the multiple openings may be arranged in a wide variety of layouts across the surface of the inner gate. Further, the openings may have a wide range of sizes and shapes.

[0047] Preferably, at least one dimension of the opening is smaller than the smallest dimension of the product for which the hopper is intended to be used, so that the product cannot pass through the opening, and equally preferably, the dimension of the opening is larger than the largest dimension of the slack, so that the slack can pass through the opening.

[0048] For example, the smallest dimension of each opening in the plane of the internal gate is preferably in the range of 0.1 cm to 1 cm, preferably in the range of 0.1 cm to 0.5 cm. The term "smallest dimension" should be understood to mean the smallest dimension of the opening in the plane of the internal gate. For example, if the opening is circular, its smallest dimension is the diameter of the opening. On the other hand, if the opening is elongated, its smallest dimension is its width perpendicular to the direction in which the opening extends.

[0049] The above dimensions are suitable for a wide range of applications, particularly in the food packaging industry. For example, an internal gate with an opening having at least one dimension ranging from 1 cm to 0.1 cm is suitable for separating lightly coated sugar from confectionery, for separating excess seasoning from crisps and chips, and for separating excess marinade from marinated meat products. However, for other mixtures of products and slacks, openings of other dimensions may be selected.

[0050] In a preferred example, the internal gate may comprise a filter, mesh, grid, grill, gauze, sieve or net. Thus, the internal gate comprises a plurality of openings arranged in a regular or irregular array.

[0051] In contrast, the outer gate may be formed of a continuous sheet of material. For example, the outer gate may be constructed of sheet or plate metal with no openings or holes therethrough. In this manner, the outer gate does not allow the passage of both product and slack. However, in alternative embodiments, the outer gate may have a small number of openings or openings that are small enough in size to allow neither slack nor product to pass through.

[0052] The inner gate, outer gate, and / or any fixed walls of the hopper are formed from metals, alloys, plastics, or composite materials, such as stainless steel, steel, and aluminum (although other suitable materials may be used). In a preferred example, the hopper gate and walls may be constructed from folded stainless steel (although this is not required).

[0053] In a preferred embodiment, the surface roughness Ra (i.e. the average deviation of the surface) of the inner gate, the outer gate and / or any fixed wall of the hopper is less than 10 μm, more preferably less than 5 μm, more preferably less than 2 μm. In a particularly preferred embodiment, the surface roughness is less than 1.6 μm. The use of a material with a low surface roughness can prevent the product and / or slack from adhering or sticking to the hopper. Additionally or alternatively, the inner gate, the outer gate and / or any fixed wall of the hopper may be provided with a surface relief configured to reduce friction between the hopper and the product and / or slack, thereby preventing the product and / or slack from adhering to the hopper surface.

[0054] In a particularly preferred embodiment, the hopper comprises two opposing internal gates and / or two opposing external gates. By opposing gates, it is meant that the free ends (e.g. lower ends) of the opposing gates face or abut when the opposing gates are in their respective closed positions. On the other hand, when the opposing gates are in their respective open positions, the free ends are laterally spaced apart and define an opening through which the product leaves the hopper (e.g. under gravity). That is, the two opposing internal gates are configured to close to each other when they are in their respective closed positions, and similarly, the two opposing external gates are configured to close to each other when they are in their respective closed positions. In practice, the hopper is closed by two consecutive "double door" pairs in the form of internal and external gates.

[0055] Thus, in a preferred embodiment, the internal gate is a first internal gate and the external gate is a first external gate. The hopper further comprises a second internal gate configured to pass slack but not product, the first and second internal gates facing each other, and a second external gate configured to pass neither product nor slack, the first and second external gates facing each other. The second internal gate and the second external gate are movable between their respective open and closed positions. The hopper is configured such that when the first and second internal gates and the first and second external gates are in their respective closed positions and a mixture is introduced into the hopper, the product is retained by the first and second internal gates, while the 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, the product leaves the hopper along the first path.

[0056] The device may be configured to move the first and second internal gates between their respective open and closed positions substantially simultaneously (i.e., coordinated or simultaneous). Similarly, the device may be configured to move the first and second external gates between their respective open and closed positions substantially simultaneously. Thus, the movement of the first and second internal gates may be mirrored and the movement of the first and second external gates may also be mirrored.

[0057] The first and second internal gates may each include any of the internal gate features described above. In a preferred embodiment, the first and second internal gates are substantially identical and mirrored about the centerline of the hopper (although this is not required). Similarly, the first and second external gates may each include any of the external gate features described above, and the first and second external gates are substantially identical and mirrored about the centerline of the hopper (also not required).

[0058] Hoppers with opposing gates (so-called "double doors") are particularly suitable for use with sticky products and / or slack (e.g., meat coated with marinades, sticky confections, etc.). In these instances, the product and / or slack may adhere or stick to the inside of the hopper. Opposing gates, especially opposing gates that open and close at approximately the same time, exert a greater force on the contents of the hopper, preventing the product and / or slack from sticking to the inside of the hopper. Such "double doors" hoppers are therefore more stable and reliable when discharging sticky products.

[0059] In some embodiments, the hopper may be a weigh hopper, a pool hopper, a booster hopper, a timing hopper, an output hopper, or a discharge hopper. Such hoppers are commonly used in computer controlled weigh scales and other product processing equipment. Thus, the product processing equipment can benefit from a reduced degree of slack in the product line.

[0060] According to a further aspect of the present invention there is provided a system comprising one or more hoppers according to the previous aspect of the present invention, each of which comprises any of the preferred or optional features described above.

[0061] The system includes a vacuum pump connected to a first hopper of the one or more hoppers, the vacuum pump configured to collect slack that exits the first hopper along the second path. The vacuum pump thus provides suction to remove or draw slack from the first hopper. In some cases, the collected slack may be reintroduced into the system upstream of the first hopper to reduce waste. The vacuum pump may be connected to multiple hoppers of the one or more hoppers to collect slack from the multiple hoppers. Alternatively, each hopper may be connected to a separate vacuum pump.

[0062] Additionally or alternatively, the system may include one or more vacuum pumps to collect slack discharged from each hopper along the first path (e.g., by opening the outer gate of the first hopper while keeping the inner gate of the first hopper closed).

[0063] The system may further comprise a tube configured to connect to a first hopper of the one or more hoppers, the second path extending through the tube, such that the slack can exit or be discharged from the hopper through the tube (although this is not required). The advantages of these tubes are discussed above, and these tubes may be provided as rigid or flexible tubes to meet any cleaning or maintenance requirements of the system. Preferably, each hopper may be connected to a separate tube.

[0064] Preferably, the system comprises a weighing system such as a combination weigher, a multi-head weigher, a screw feed weigher, a cut gate weigher, a linear weigher or a mixed weigher. Used in combination with the above hoppers, these machines can output a given volume or weight of product accurately, quickly and with a reduced degree of slack. The weighing system may comprise a plurality of hoppers, preferably a plurality of hoppers according to the first aspect of the invention. For example, the weigher may comprise a plurality of hoppers as described above, arranged in a circumferential direction and fed by a feeding device (e.g. a distributed feeding device).

[0065] In a preferred example, the system includes a packaging machine, preferably a bag maker, tray sealer, box maker, or thermoformer, such that a product stream having a reduced slack discharged from one or more hoppers can be fed into an appropriate container within the packaging machine, such that the system can output or produce a packaged product having a reduced slack output by the system.

[0066] As described above, it is particularly advantageous to provide a hopper immediately upstream of the packaging machine, as slack can be removed at the last stage before the product is packaged. Thus, preferably, the hopper is configured to distribute the product to the packaging material of the packaging machine along a first path. As described above, the product may fall directly onto the packaging material of the packaging machine and / or the product may pass through one or more funnels or chutes by way of the first path before entering the packaging material.

[0067] Further advantages of the system according to the invention have been described above with reference to the first aspect of the invention. These systems may comprise any of the preferred or optional features described above.

[0068] According to a further aspect of the invention, there is provided a method for separating slack from a mixture of product and slack, (a) introducing a mixture of product and slack into a hopper, the hopper comprising an internal gate configured to allow slack but not product to pass through, and an external gate configured to prevent both product and slack from passing through, the internal and external gates being movable between their respective open and closed positions, and when the internal and external gates are in their respective closed positions and the mixture is introduced into the hopper, the product is retained by the internal gate and the slack is retained by the external gate; (b) recovering the slack retained by the external gate; (c) moving the internal and external gates to their respective open positions and discharging the product retained by the internal gate from the hopper via a first path.

[0069] By this method, slack can be removed from the product stream. The contents of the hopper discharged by opening the internal and external gates in step (c) have a reduced degree of slack compared to the mixture introduced into the hopper in step (a). Thus, according to this method, a very reliable and improved quality product is provided. Further advantages of this method have been described above with reference to the first aspect of the invention.

[0070] Preferably, the step of recovering the slack held by the external gate comprises either a step of enabling the slack held by the external gate to be discharged from the hopper via a second path different from the first path, or a step of moving the external gate to an open position while maintaining the internal gate in a closed position so that the slack held by the external gate exits the hopper via the first path.

[0071] Thus, in the first case, the excess slack is separated from the product by an internal gate in the hopper and directed out of the hopper along a different path than the product (e.g., allowing the excess slack to be collected and reused), while in the second case, the excess slack separated by the internal gate is directed out of the hopper along the same path as the product. Unlike the first case, the excess slack and the product are discharged at different times, and the excess slack and the product are separated in time, rather than in space (as in the previously described method in which the slack and the product are discharged from the hopper along different paths). In a further example, the slack separated by the internal gate and retained by the external gate may be manually removed (i.e., collected) from the hopper.

[0072] It will be appreciated that in some embodiments, a single device or system may be configured to perform either or both of these method steps. For example, the device and system may be switched (i.e., the device or system may be controlled to switch) between two different modes. In a first mode, the device or system performs a first method, and in a second mode, the device or system performs a second method, although this is not required.

[0073] In a preferred example, the step of recovering the slack retained by the external gate comprises operating a vacuum pump to recover the slack from the hopper. The vacuum pump may be operated continuously or periodically. For example, the vacuum pump may be operated simultaneously with step (b) in each manner in which excess slack is discharged from the hopper. Depending on the configuration of the system, the vacuum pump recovers the slack exiting the hopper along either the first path or the second path.

[0074] In a further preferred embodiment, the method comprises: (d) moving the inner gate and the outer gate to their respective closed positions; Steps (a) to (d) are performed repeatedly, preferably with each repetition of step (c) occurring at least 100 ms after the previous repetition of step (d), preferably at least 200 ms after the previous repetition of step (d), more preferably at least 300 ms after the previous repetition of step (d), more preferably at least 400 ms after the previous repetition of step (d). This delay allows time for slack to separate in the hopper before the product is discharged. The greater the delay, the less slack there will be in the final product, resulting in a higher quality. However, when the hopper distributes the product to the packaging material of the packaging machine, it is desirable for each repetition of step (c) to occur at most 1000 ms after the previous repetition of step (d), preferably at most 800 s after the previous repetition of step (d), more preferably at most 600 ms after the previous repetition of step (d), and most preferably at most 500 ms after the previous repetition of step (d). Reducing the delay between each repetition helps maintain overall system throughput, which is particularly important when the packaging machine is bottlenecked at a hopper dispensing packaging material. In a preferred range, each repetition of step (c) occurs between 200 ms and 800 ms, preferably between 400 ms and 600 ms, after the preceding repetition of step (d).

[0075] In alternative examples, the hopper may form part of a scale, such as a computer combination weigher (CCW). In such examples, a longer delay time may be preferred to more accurately measure the weight of the product. In such examples, since multiple hoppers of the scale may simultaneously weigh and selectively dispense amounts of product to form predetermined weight batches, a longer delay may have less impact on the overall system throughput and therefore may be preferred to improve slack removal. In such examples, it is preferred that each repetition of step (c) occurs at least 400 ms after the preceding repetition of step (d), preferably at least 600 ms after the preceding repetition of step (d), more preferably at least 800 ms after the preceding repetition of step (d), and more preferably at least 1000 ms after the preceding repetition of step (d). However, the delay time may be defined to strike a balance between settling time and throughput of the apparatus.

[0076] The inner and outer gates may be returned to their respective closed positions at approximately the same time or simultaneously, although this is not required.

[0077] As mentioned above, this hopper can be integrated into a weighing system, in which case the method additionally or alternatively comprises, following step (c), (i) obtaining weight measurements of the contents of the hopper over time; (ii) determining that the weight of the contents of the hopper has stabilized based on the weight measurements, where step c) is performed only if this determination is made.

[0078] Thus, the weight of the contents of the hopper is monitored and the contents of the hopper are discharged only when the measurements are stable, i.e., the weight of the contents of the hopper is precisely known. For example, the weight measurements may be taken continuously or periodically (e.g., every 10 ms). In a further example, the weight measurements may be taken at least every 0.5 s, preferably at least every 0.25 s, more preferably at least every 0.1 s, and even more preferably at least every 0.05 s. The weight of the contents of a particular hopper may be determined to be stable when two or more consecutive measurements (e.g., three consecutive measurements) have the same value and / or when the difference or range of two or more consecutive measurements is less than a predetermined value (e.g., less than 1 g, more preferably less than 0.5 g, and even more preferably less than 0.15 g).

[0079] The method may further comprise transferring the product leaving the hopper via the first path into a packaging component, followed by sealing the packaging component. This may be performed in a bag-making machine, a tray-sealing machine, a box-making machine, or a thermoforming machine. The packaging components filled in this step may be bags, trays, or boxes (although other packaging components may be suitable). The final packaged goods have a reduced degree of slack and improved quality.

[0080] In a preferred embodiment, the method may be carried out using any of the devices or systems described above with reference to the preceding aspects of the invention. Furthermore, further optional preferred features of the method have been described above with reference to the preceding aspects of the invention (i.e. the devices and systems described above). Similarly, a number of further advantages achieved using the method have also been detailed above in relation to the devices and systems. [Brief description of the drawings]

[0081] [Figure 1a] 1A-1D are schematic cross-sectional views of an apparatus according to the invention, showing the successive configurations of the apparatus when it carries out a method according to the invention; [Figure 1b]1A-1D are schematic cross-sectional views of an apparatus according to the invention, showing the successive configurations of the apparatus when it carries out a method according to the invention; [Figure 1c] 1A-1D are schematic cross-sectional views of an apparatus according to the invention, showing the successive configurations of the apparatus when it carries out a method according to the invention; [Figure 2a] 3 is a schematic cross-sectional view of a further device according to the invention; [Figure 2b] 3 is a schematic cross-sectional view of a further device according to the invention; [Diagram 3] 3 is a schematic cross-sectional view of a further device according to the invention; [Figure 4a] 1A-1D are perspective views of a further device according to the invention in a closed and an open configuration, respectively; [Figure 4b] 1A-1D are perspective views of a further device according to the invention in a closed and an open configuration, respectively; [Figure 4c] FIG. 2 is a cross-sectional view of the device in a closed configuration. [Figure 4d] FIG. 2 is a side view of the device in an open configuration. [Figure 4e] FIG. 2 is another cross-sectional view of the device in a closed configuration. [Diagram 5] FIG. 4B is a schematic diagram showing a preferred location of the device of FIGS. 4a to 4d in a system according to the invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0082] Figures 1a, 1b and 1c show a hopper 10 suitable for removing slack S from a mixture of product P and slack S. Slack S is thus a solid particle (e.g. excess sugar) of significantly smaller dimensions than product P. More specifically, the dimensions of slack S shown in Figures 1a to 1c are approximately an order of magnitude smaller (i.e. 10 times smaller) than the dimensions of product P. However, the hopper 10 is also suitable for use with mixtures containing liquid slack or solid slack having another dimension relative to the product.

[0083] The hopper 10 has an upper opening 11 through which the product P and slack S can be introduced into the hopper 10 (as shown in FIG. 1a). The hopper 10 has two gates, an inner gate 12 and an outer gate 14.

[0084] The internal gate 12 comprises a number of openings 13 extending therethrough (i.e., between two opposing sides of the internal gate). The openings 13 are sized to allow slack S to pass through them (and thus through the internal gate 12) but not product P. Thus, the internal gate 12 is configured to remove or separate the slack S from the product P. The dimension of each opening 13 in the plane of the internal gate 12 is greater than the maximum dimension of the slack S and less than the minimum dimension of the product P.

[0085] In contrast, the outer gate 14 is continuous and does not form any openings. Neither product P nor slack S can pass through this solid outer gate 14. The outer gate 14 is located lower than the inner gate 12, which is located within the hopper 10 (i.e., within the interior volume of the hopper 10 defined by the side walls 16a, 16b and the outer gate 14) so ​​that the slack that passes through the inner gate 12 is retained by the outer gate 14.

[0086] The internal gate 12 is connected to the first side wall 16a of the hopper 10 by a hinge 12a about which the internal gate 12 can rotate. The internal gate 12 is movable between two positions: a closed position, shown in Figures 1a and 1b, in which the internal gate 12 extends between the hopper's side walls 16a, 16b, and an open position, shown in Figure 1c, in which the internal gate 12 hangs from the hinge 12a such that a gap is provided between the distal or free end of the internal gate 12 and the second side wall 16b of the hopper 10.

[0087] Similarly, the outer gate 14 is connected to the first side wall 16a of the hopper 10 by a hinge 14a about which the outer gate 14 can rotate. Like the inner gate 12, the outer gate 14 is positionable in two positions: a closed position, shown in Figures 1a and 1b, in which the inner gate 14 extends between the side walls 16a, 16b of the hopper so as to close the bottom opening 19 of the hopper 10, and an open position, shown in Figure 1c, in which the outer gate 14 hangs from the hinge 14a such that a gap is formed between the distal or free end of the outer gate 14 and the second side wall 16b of the hopper 10. When the outer gate 14 is in the open position (as shown in Figure 1c), the bottom opening 19 of the hopper 10 is open to allow the contents of the hopper 10 to exit the hopper 10.

[0088] A method for separating slack S from a mixture of product P and slack S will now be described with reference to Figures 1a, 1b and 1c, which show a series of steps carried out using a hopper 10.

[0089] First, a mixture of product P and slack S (as shown in FIG. 1a) is introduced into the hopper 10 while the inner gate 12 and outer gate 14 are in their respective closed positions.

[0090] The product P and slack S entering the hopper 10 impinge on the internal gate 12. The slack S passes through an opening 13 in the internal gate 12, but the product P does not. Thus, the product P is retained by the internal gate 12, but some (preferably substantially all) of the slack S contained in the hopper 10 moves through the internal gate 12. The slack S that passes through the internal gate 12 falls into the external gate 14 below. Thus, the slack S that passes through the internal gate 12 is retained or captured by the external gate 14 below. This results in the arrangement shown in FIG. 1b.

[0091] From Figure 1b it can be seen that a small amount of slack S may remain in the product P retained in the internal gate 12. In many cases it is preferable to remove most of the slack S (e.g., at least 75% of the slack or at least 90% of the slack) from the mixture of product P and slack S. However, in practice it may be difficult and / or unnecessary to separate all of the slack S from the product P.

[0092] It will be appreciated that the percentage of slack S removed from the mixture using the hopper can be controlled by, for example, varying the length of time the mixture resides in the hopper 10 (i.e., the residence time of the product P), the size and distribution of the openings in the internal gate 12, and the size of the hopper 10. By varying these parameters, the percentage of slack S removed from a given mixture of slack S and product P can be varied.

[0093] Once the slack S has been separated from the product P by the internal gate 12, the separated slack S may be discharged from the hopper 10. The slack S may be automatically or manually collected and reintroduced into the production line upstream of the hopper 10 to reduce waste. For example, 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 while keeping the internal gate 12 closed and discharging only the separated slack S through the hopper bottom opening 19 (although other techniques may be used).

[0094] Thereafter, the product P held by the inner gate 12 may be discharged or dispensed by the hopper 10, as shown in Figure 1c. The remaining contents of the hopper 10 are discharged by simultaneously opening the inner gate 12 and the outer gate 14, i.e., by moving the inner and outer gates to their respective open positions. Figure 1c illustrates this process, showing the product P passing through the bottom opening 19 of the hopper 10.

[0095] In this manner, product P (and any remaining slack S) exits hopper 10 along a first path that extends through a lower opening 19 of hopper 10. It can be seen that the product mix discharged by hopper 10 of Figure 1c has significantly less slack S than the product mix introduced into hopper 10 of Figure 1a.

[0096] The process can be repeated by returning the inner gate 12 and outer gate 14 to their closed positions (as shown in FIG. 1a) and refilling the hopper 10 with another mixture of product P and slack S.

[0097] A delay time may be provided between closing the inner gate 12, the outer gate 14 and reopening the inner gate 12, the outer gate 14. This delay time allows the mixture of product P and slack S to enter the hopper 10 and allows the slack S to be separated and removed from the hopper 10. Additionally, this delay time allows the remaining contents of the hopper 10 to settle and the weight of the hopper contents to stabilize. The delay time may be, for example, 400 ms or 800 ms.

[0098] Additionally or alternatively, the weight of the contents of the hopper 10 may be monitored periodically or continuously, and the gates 12, 14 of the hopper 10 may be opened once the weight of the hopper 10 has stabilized (indicating that the contents of the hopper 10 have settled and removed excess slack S) and not opened before then. For example, measurements of the weight of the contents of the hopper 10 may be taken periodically, e.g., once every 10 ms. The weight of the contents of the hopper 10 may be determined to be stable if three consecutive measurements are the same value or if the measurements are within a predetermined range, e.g., 0.15 g.

[0099] The product P discharged by the hopper 10 may then be transferred to or fed into a packaging component (e.g., a bag, tray, or box). The method may further comprise sealing the packaging component (e.g., using a bag-making machine, tray sealer, cartoniser, or thermoformer).

[0100] Figures 2a and 2b show a variant of the hopper 10 of Figures 1a, 1b and 1c, which is also suitable for separating slack S from product P using the method described above and shares many of the features and advantages of the hopper 10 shown in Figures 1a, 1b and 1c. Corresponding features of the two hoppers 10, 10' are indicated by reference numbers followed by a prime symbol (').

[0101] The hopper 10' of Figures 2a and 2b comprises two side walls 16a', 16b' between which is formed an upper opening 11' through which product and slack can be introduced into the hopper 10'. The hopper 10' comprises an inner gate 12' and an outer gate 14', the outer gate 14' being located below the inner gate 12' (as shown).

[0102] The inner gate 12' has a number of openings 13' sized to allow slack to pass through the inner gate 12' but not product. Thus, the inner gate 12' is capable of removing slack from the product and slack mixture. In contrast, the outer gate 14' is continuous and is formed without gaps or openings, preventing slack from passing through the outer gate 14'.

[0103] The inner gate 12' and the outer gate 14' are rotatable about respective hinges 12a', 14a' and connected to a first side wall 16a' of the hopper 10'. Thus, the inner gate 12' and the outer gate 14' are movable between respective open and closed positions.

[0104] 2b shows the inner gate 12' and outer gate 14' in an open position. This position defines a lower opening 19' for the hopper 10'. The contents of the hopper 10' can be removed by the flow of air through the lower opening 19' as indicated by arrow R. 1 The material exits the hopper 10' along a first path which extends through the lower opening 19', as indicated by .

[0105] Unlike the previous examples, the hopper 10' of Figures 2a and 2b comprises a slack recovery duct 17 provided in the second side wall 16b' of the hopper 10'. This slack recovery duct 17 passes through the inner gate 12' and can be used to recover the slack held by the outer gate 14'.

[0106] Therefore, the slack is transferred to the second path (arrow R 2 The slack can exit the hopper 10' along a first path (shown as a slack recovery duct 17) and a second path extends through the slack recovery duct 17. As can be seen, the second path is at an angle laterally offset from the first path.

[0107] The hopper 10' is configured such that the slack recovery duct 17 is located at the lower end of the second side wall 16b'. Furthermore, the external gate 14' is angled relative to the horizontal such that when the external gate 14' is in the closed position (as shown in FIG. 2a), the external gate 14' is inclined towards the slack recovery duct 17. This causes any slack that reaches the closed external gate 14' to flow towards the slack recovery duct 17 and out of the hopper 10' along the second path.

[0108] A vacuum pump (not shown) may be connected (e.g., via flexible tubing) to the slack recovery duct 17 to draw the slack out of the hopper 10'. Alternatively, the slack may flow unassisted under gravity along the second path R. 2 and may pass through a slack recovery duct 17.

[0109] 3 illustrates another hopper 20 with a "dual door" configuration that is suitable for use with sticky products that may adhere to the side walls and gates of "single door" hoppers (such as hoppers 10, 10' shown in FIGS. 1 and 2).

[0110] The hopper 20 has an upper opening 21 formed between a pair of side walls 26a, 26b. Provided between the side walls are a pair of opposing internal gates 22 and a pair of opposing external gates 24 (shown in their closed positions in FIG. 3). Each internal gate 22 has a number of openings 23 through which slack, but not product, can pass. Each internal gate 22 and each external gate 24 is rotatable about a corresponding hinge 22a, 24a between a closed position and an open position.

[0111] 3 shows the inner gate 22 and the outer gate 24 in a closed position. As can be seen, the inner gate 22 projects from each of the side walls 26a, 26b of the hopper 20 such that the free ends of the inner gate 22 meet at the center of the hopper 20. Similarly, the outer gate 24 projects from the side walls 26a, 26b of the hopper 20 such that the free ends meet at the center of the hopper 20.

[0112] In this configuration, slack can be removed from a mixture of product and slack introduced into the hopper 20. Slack introduced into the interior volume of the hopper 20 can pass through openings 23 in the inner gate 22, but product cannot. The separated slack is then retained by the underlying outer gate 24, which is a continuous plate with no openings.

[0113] The separated slack may then be removed and collected from the hopper 20. For example, the separated slack may be manually removed from the hopper 20 by opening only the exterior gate 24 or by operating a vacuum pump (not shown). In a further example, a slack collection duct or an opening in the wall of the hopper 20 may be provided through which the slack may exit the hopper 20.

[0114] Thereafter, the inner gate 22 and the outer gate 24 can be moved to their respective open positions to allow any product remaining within the hopper 20 to be discharged from the hopper 20. Thus, the hopper 20 can be used to discharge a product mix with a reduced amount of slack, i.e., a mix from which the slack has been removed.

[0115] It will be understood that the hoppers 10', 20 shown in Figures 2 and 3 may include any of the preferred or optional features described for the hopper 10 shown in Figure 1 (and vice versa). Similarly, the hoppers 10', 20 of Figures 2 and 3 are capable of performing the corresponding steps of the method described for the hopper 10 of Figure 1.

[0116] A further hopper 30 with a "double door" suitable for separating slack from the product and slack mixture is shown in Figures 4a to 4e.

[0117] The hopper 30 includes a pair of opposing outer gates 34. Each of the outer gates 34 is rotatable relative to a side wall 36 of the hopper 30 between a closed position (shown in FIGS. 4a, 4c, and 4e) and an open position (shown in FIGS. 4b and 4d). When each of the outer gates 34 is in the closed position, the free ends of the outer gates 34 face or abut at the center of the hopper 30, closing a lower opening 39 of the hopper 30. On the other hand, when each of the outer gates 34 is in the open position, the outer gates 34 are laterally offset or spaced apart, with the lower opening 39 extending between the outer gates 34.

[0118] Rotation of each exterior gate 34 is controlled using a corresponding lever arm 34b. Each lever arm 34b is fixed to a corresponding exterior gate 34 and rotatably connected to a side wall 36 of the hopper 30 by a hinge (not shown) that extends through a hole 34c in the lever arm 34b and through the side wall 36 of the hopper 30.

[0119] The hopper 30 further includes a pair of opposing internal gates 32. Each internal gate 32 is fixedly coupled to a corresponding external gate 34 by a coupling 35 (as best seen in FIG. 4c). Each internal gate 32 extends parallel to the attached external gate 34 (although this is not required). The connection between the corresponding internal gates 32 and external gates 34 may be permanent (e.g., the gates 32, 34 are joined using welding or adhesive) or non-permanent (e.g., using threaded fasteners such as screws).

[0120] Because the inner gates 32 are fixed to the outer gates 34, each inner gate 32 rotates with its attached outer gate 34. Each inner gate 32 is therefore movable between open and closed positions by moving the corresponding outer gate 34 between the open and closed positions.

[0121] When the internal gates 32 are in their respective closed positions, they face each other at the center of the hopper 34. Each internal gate 32 has an array of openings 33 extending therethrough. The openings 33 are sized such that relatively large product does not pass through the internal gates 32, but relatively small or liquid slack does pass through the internal gates 32. Thus, the internal gates 32 function as a filter, separating product and slack when each internal gate 32 is in its respective closed position.

[0122] As shown, each interior gate 32 is comprised of a repeating array of oval shaped openings 32. However, it will be understood that openings having a wide variety of sizes and configurations may be selected for use in the hopper 30 depending on the intended product and slack mix.

[0123] When the inner gate 32 and the outer gate 34 are placed in the closed position (as shown in FIG. 4c, which is a cross-sectional view taken along line EE of FIG. 4e), and a mixture of product and slack is introduced into the hopper 30, the product is retained by the inner gate 32, but the slack passes through the inner gate 32 and falls towards the outer gate 34 below.

[0124] Each outer gate 34 further includes a recess 38 (best seen in FIG. 4c), which is an open channel or duct capable of receiving slack after it has passed through the overlying inner gate 32. In particular, the hopper 30 is configured such that when the inner and outer gates 32, 34 are in their respective closed positions, slack that has passed through the inner gate 32 falls into the outer gate 34 and accumulates within the recess 38.

[0125] When each of the outer gates 34 is in its closed position, the outer gate 34 is angled relative to the corresponding recess 38. Indeed, when each of the outer gates 34 is in its closed position, the outer gate 34 is angled downward from the end proximate the corresponding hinge and lever arm 34b toward the free end that includes the recess 38. Because each of the outer gates 34 is angled toward the corresponding recess 38 when each of the outer gates 34 is in its closed position, slack that reaches the outer gate 34 after passing through the inner gate 32 falls or flows (e.g., under gravity) along the surface of the outer gate 34 and into the recess 38.

[0126] The bottom 38a of each depression 38 is angled relative to the horizontal such that the depth of the depression 38 increases along the length of the depression 38. Thus, slack that accumulates in the depression 38 flows or moves laterally (e.g., under the force of gravity) along the bottom 38a of the depression 38.

[0127] The hopper 30 further includes a slack collection duct 37 connected to the lower edge of each of the external gates 34. More specifically, each of the slack collection ducts 37 connects to the lower end of the corresponding recessed portion 38. Thus, slack that passes through the internal gate 32 and falls into the external gate 34 flows into or out of the recessed portion 38 along the angled surface of the external gate 34, and then flows into or out of the slack collection duct along the angled bottom 38a of each recessed portion 38. In this manner, each recessed portion 38 communicates with the corresponding slack collection duct 37, and the slack leaves the hopper 30 along a path (i.e., a second path) that extends from each recessed portion through the corresponding slack collection duct 37. This path is offset and angled with respect to a substantially vertical path (i.e., a first path) through which the contents of the hopper 30 pass through the lower opening 39 of the hopper when the internal and external gates 32, 34 are moved to the open position.

[0128] The passage of the slack in the hopper 30 through the slack collection duct 37 can occur under gravity by vibrating the hopper and / or the slack collection duct 37 and / or by connecting a vacuum pump (not shown) to the slack collection duct 37 to apply suction.

[0129] The slack connection duct 37 may be a rigid tube as described above, but may also be connected to a flexible tube (not shown). A flexible tube can accommodate the change in position of the slack removal duct 37 as the external gate 34 of the hopper 30 opens and closes. For example, a vacuum pump may be connected to the slack connection duct 37 via a flexible tube. However, this is not required, and in further embodiments, the slack removal duct 37 itself may be made of a flexible material and / or may be directly connected to the vacuum pump or reservoir. In such a case, the slack can continue to travel along a second path that continues through the flexible tube.

[0130] 4a-4e, it will be appreciated that slack will exit the hopper whether the exterior gate 34 is in the closed or open position as the slack flows from the recess 38 into the slack collection duct 37. Thus, excess slack can continue to be discharged from the hopper 30 without delaying the timing of the hopper 30 discharging the remaining contents.

[0131] Thus, when a mixture of product and slack is introduced into the hopper 30, the slack is separated from the product by the inner gate 32. The separated slack accumulates in the recess 38 of the outer gate and leaves the hopper for collection through the slack collection duct 37. The remaining contents of the hopper are then discharged through the lower opening 39 of the hopper 30 by opening the inner and outer gates 32, 34.

[0132] The contents of the hopper may be discharged only after the contents of the hopper 30 have settled. For example, the inner and outer gates 32, 34 of the hopper 30 may only be opened after a predetermined delay time has elapsed (e.g., 400 ms, 800 ms, or 1000 ms) or when the weight of the contents of the hopper has stabilized (e.g., when the weight measurement of the hopper is constant or within a predetermined tolerance).

[0133] The discharged product with reduced slack dispensed by hopper 30 may then be packaged using packaging equipment and / or further processed and / or retouched by subsequent machinery. Subsequent packaging and product handling operations are more reliable and of higher quality due to the reduced slack.

[0134] Any of the above hoppers may be installed in a larger product handling system.

[0135] For example, these hoppers may be provided as part of a weighing system and used to precisely dispense a predetermined amount of product with reduced slack. The product processing system may further include a packaging device for packaging the product after it is discharged. Alternatively, the product may continue along the production line for further processing in subsequent machines. By dispensing reduced slack using the above-described hoppers, subsequent packaging and product processing operations are more reliable and provide higher quality packaged goods.

[0136] Referring now to FIG. 5, a preferred embodiment of the hopper of FIGS. 4a-4d installed in a system according to the invention will be described.

[0137] FIG. 5 is a schematic diagram of the hopper 30 described above installed in a system 100 for forming product batches having predetermined weights and providing these constant weight batches to a packaging machine.

[0138] The system 100 comprises a combination weigher 200 located upstream of the hopper 30. An example of a suitable combination weigher is the RV-series multi-head weigher sold by Ishida Europe Limited, 11 Kettle's Wood Drive, Woodgate Business Park, Birmingham B32 3DB.

[0139] In general, the combination weigher comprises a series of weighing hoppers 210 (only two of which are shown in FIG. 5 ), arranged in a circle around a central axis. Each weighing hopper is fed by a feeding device, such as a product dispersion table, and receives a certain amount of product. The weight of the products in each hopper is continuously monitored, and the combination weigher selects any two or more hoppers whose total weight meets a criterion for the weight of the product batch to be formed, distributes the products from the selected hoppers, and combines these products into a single product batch having a desired weight. In this embodiment, the illustrated combination weigher 200 has a funnel 220 surrounding all the weighing hoppers 210 to combine the products distributed by any two or more weighing hoppers 210 and deposit the products in the slack separation hopper 30. It should be noted that each weighing hopper 210 can also be formed as a slack separation hopper according to the present invention, but this is not required.

[0140] This provides the slack separation hopper 30 with a mixture of product and slack having a weight that meets the predetermined weight criteria for the product batch. The mechanism described above removes slack from the hopper 30, but this typically has little effect on the weight of the product batch. If a significant amount of slack is removed in the hopper 30, it is generally possible to adjust the amount in the combination weigher 200 by forming a batch that is a predetermined amount heavier to compensate for the expected weight loss due to the slack being removed. Upon receiving the product batches, the hopper 30 distributes the product batches to a packaging machine 300 located downstream.

[0141] Figure 5 shows diagrammatically only part of a packaging machine 300. An example of a packaging machine suitable for use in the present system is the Astro Bagmaker sold by Ishida Europe Limited, 11 Kettle's Wood Drive, Woodgate Business Park, Birmingham B32 3DB.

[0142] The packaging machine 300 includes a former 310 that forms the feed film into a cylindrical shape that is sealed at intervals by a sealer (not shown) to form individual bags. The former 310 includes an inner forming tube 311 and an outer forming ring 312 that together form the feed film into a cylindrical shape. The packaging machine further includes a funnel 320 that connects to the top opening of the inner forming tube 311 and feeds product into the interior of the bag being formed.

[0143] In this system, a hopper 30, which receives product from the scale 200 and separates the slack, distributes product batches along a first path such that the hopper opens and gravity allows the product to fall vertically into a funnel 320 of a packaging machine 300, which receives the product into a package formed by the packaging machine, i.e., into a bag. Product is typically discharged by the hopper 30 as a bottom seal of the bag is formed, and as the product is received in the bag, a top seal is made to seal the bag, which then forms the bottom seal for the next bag, and the process is repeated.

[0144] The timing of opening of the hopper 30 to distribute product to the packaging machine is typically controlled by a system controller (not shown) which collectively controls the weigher 200, hopper 30, and packaging machine 300 of the system 100. Typically, the system operates in one cycle every 100-1000 ms, most typically about 500 ms. That is, product batches are distributed by the hopper 30 at regular intervals of about 500 ms to match the rate at which packaging material is produced by the packaging machine 300.

[0145] While the above system shows the hopper 30 integrated between the weigher 200 and the packaging machine 300, it will be appreciated that the hopper 30 is suitable for use anywhere along the production process of the product and slack mixture. For example, as discussed above, the hopper can be incorporated into the weigher 200 or can be incorporated as part of the feed to the weigher 200.

Claims

1. 1. A hopper for separating slack from a mixture of product and slack, comprising: an internal gate configured to pass slack but not product; an exterior gate configured to prevent the passage of product and slack; Equipped with the inner gate and the outer gate are movable between respective open and closed positions; when the inner gate and the outer gate are in their respective closed positions and the mixture is introduced into the hopper, product is retained by the inner gate, but slack passes through the inner gate and is retained by the outer gate; With the outer gate and the inner gate in their respective open positions, product exits the hopper along a first path; a second path, different from the first path, is provided for discharging slack held by the outer gate from the hopper when the outer gate is in a closed position; Hopper.

2. the second path being angled and / or laterally offset relative to the first path; 2. The hopper of claim 1.

3. The lower end of the outer gate has a recessed portion, the recess receives slack when the outer gate is in a closed position.

3. A hopper according to claim 1 or 2.

4. When the exterior gate is in a closed position, slack travels along the recess and exits the hopper along the second path.

4. The hopper of claim 3.

5. the bottom of the recess is angled to allow slack to move along the recess under gravity; 5. A hopper according to claim 3 or 4.

6. the hopper is connected to a vacuum pump configured to collect slack exiting the hopper along the second path. A hopper according to any one of claims 1 to 5.

7. The hopper is connected to a pipe; the second passageway extends through the tube; A hopper according to any one of claims 1 to 6.

8. the inner gate is fixed relative to the outer gate; A hopper according to any one of claims 1 to 7.

9. moving the outer gate between the closed and open positions independently of the inner gate such that when the outer gate is in the open position and the inner gate is in the closed position, product is retained by the inner gate and slack exits the hopper in a first direction. A hopper according to any one of claims 1 to 7.

10. the internal gate having one or more openings; each of said openings is sized to allow passage of slack but not product; A hopper according to any one of claims 1 to 9.

11. the smallest dimension of each of the openings in the plane of the internal gate is in the range of 0.05 cm to 1 cm; 11. The hopper of claim 10.

12. The inner gate comprises a filter, mesh, grate, grill, gauze, sieve, or net. A hopper according to claim 10 or 11.

13. the inner gate is a first inner gate and the outer gate is a first outer gate; a second internal gate that does not allow the product to pass but allows the slack to pass, the first internal gate and the second internal gate being opposed to each other; a second external gate that does not allow the product and the slack to pass therethrough, the first external gate and the second external gate being opposed to each other; the second inner gate and the second outer gate are movable between respective open and closed positions; when the first and second inner gates and the first and second outer gates are in their respective closed positions and the mixture is introduced into the hopper, product is retained by the first and second inner gates while slack passes through the first and second inner gates and is retained by the first and second outer gates; when said first and second interior gates and said first and second exterior gates are in their respective open positions, product exits said hopper along said first path; A hopper according to any preceding claim.

14. The hopper is a weigh hopper, a pool hopper, a booster hopper, a timing hopper, an output hopper or a discharge hopper; A hopper according to any preceding claim.

15. A system comprising one or more hoppers described in any one of claims 1 to 14.

16. a vacuum pump connected to a first hopper of the one or more hoppers; The vacuum pump collects the slack that has left the first hopper along the second path. The system of claim 15.

17. a tube configured to connect to a first hopper of the one or more hoppers; the second passageway extends through the tube; 17. A system according to claim 15 or 16.

18. The system comprises a weighing system such as a combination weigher, a multi-head weigher, a screw feed weigher, a cut gate weigher, a linear weigher, or a mixed weigher.

18. A system according to any one of claims 15 to 17.

19. The system includes a packaging machine; The packaging machine is a bag making machine, a tray sealing machine, a box making machine, or a thermoforming machine.

19. A system according to any one of claims 15 to 18.

20. the hopper is positioned to dispense product along the first path into a packaging material of the packaging machine.

20. The system of claim 19.

21. 1. A method for separating slack from a mixture of product and slack, comprising: (a) introducing a mixture of product and slack into a hopper having an inner gate configured to block product but not slack, and an outer gate configured to block product and slack, the inner gate and the outer gate being movable between respective open and closed positions, such that when the inner gate and the outer gate are in their respective closed positions and the mixture is introduced into the hopper, the product is retained by the inner gate and the slack is retained by the outer gate; (b) recovering slack held by the outer gate; (c) moving the inner gate and the outer gate to their respective open positions to eject product held by the inner gate from the hopper via a first path; Equipped with method.

22. The step of recovering the slack held by the external gate includes either a step of discharging the slack held by the external gate from the hopper via a second path different from the first path, or a step of moving the external gate to an open position while maintaining the internal gate in a closed position so that the slack held by the external gate leaves the hopper via the first path.

22. The method of claim 21.

23. The step of recovering slack held by the outer gate includes operating a vacuum pump to recover slack from the hopper.

23. The method of claim 21 or 22.

24. (d) moving the inner gate and the outer gate to their respective closed positions; Further equipped with Steps (a) to (d) are repeatedly performed; Each repetition of step (c) occurs at least 100 ms after the preceding repetition of step (d); 24. The method of any one of claims 21 to 23.

25. After step (a), (i) obtaining weight measurements of the contents of the hopper over time; (ii) determining that the weight of the contents of the hopper has stabilized based on the weight measurements; Step (c) is performed only if said determination is made.

25. The method of any one of claims 21 to 24.

26. transferring the product exiting the hopper via the first path into a packaging part, followed by sealing the packaging part.

26. The method of any one of claims 21 to 25.

27. Implemented using an apparatus according to any one of claims 1 to 14 or a system according to any one of claims 15 to 20, 27. The method of any one of claims 21 to 26.

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