GB2596069A

GB2596069A - Slack separation apparatus and method

Info

Publication number: GB2596069A
Application number: GB2009055.1A
Authority: GB
Inventors: Meredith Sunter Adrian
Original assignee: Ishida Europe Ltd
Current assignee: Ishida Europe Ltd
Priority date: 2020-06-15
Filing date: 2020-06-15
Publication date: 2021-12-22
Also published as: GB202009055D0

Abstract

A device for separating slack from a mixture of product and slack (i.e. particulate material mixed with a solid packed product) which comprises a hollow drum 12 which has a drum wall with one or more apertures 12a extending through the drum well. The apertures are sized such that slack may pass through, but not product. The device further comprises a rotation unit 14 that rotates the drum, causing the contents to be tumbled and an actuation unit that conveys the contents of the drum towards the discharge end of the drum. Preferably the minimum dimension of the apertures is less than 1 cm, more preferably less than 0.5 cm and most preferably less than 0.25 cm. Preferably the actuation unit comprises a drive unit 24 configured to cause motion of the drum. Alternatively, the actuation unit may comprise a contact portion that pushes contents of the drum towards the discharge end, more preferably this may comprise a helical surface (fig 3 320b), this may also comprise a piston (fig 4a 420b).

Description

SLACK SEPARATION APPARATUS AND METHOD

FIELD

The present disclosure relates to devices and methods for separating excess slack out from a product stream comprising a mixture of product and slack.

More specifically, aspects of the invention relate to a device which efficiently and conveniently separates slack from a product stream, systems comprising said device, and a method of separating slack from a product stream using said device. The invention offers particular benefits for the handling, manufacture and packaging of food products.

BACKGROUND

Some products are packaged together with additional material, which will be referred to herein as slack. Slack, which is generally of a substantially solid or liquid form, may be mixed with solid product before the mixture is portioned into packaging. Where slack is substantially solid, its dimensions are significantly smaller than the dimensions of the product itself (and typically at least an order of magnitude smaller than the dimensions of the product). For example, slack may be in the form of powder or particulates. In the case of coated food products the slack may be in the form of loose coating such as (for example) sugar for sugared sweets, breadcrumbs for breaded foodstuffs or seasoning for savoury snacks.

Slack may be included to protect the product in some way, for example from degradation due to exposure to certain chemicals or due to motion of the product within its packaging. Alternatively or additionally, slack may be included to enhance the product in some way, for example food products may be provided with loose coatings of sugar, breadcrumbs, herbs and/or flavourings to improve one or more of their taste, texture, appearance or smell. However, slack may also be undesirably created when processing or handling of a product, for instance, products such as potato chips or crisps may crumble or break to form slack.

For many products it is not desirable for excess slack to be allowed to float freely within the packaging. For example if excess breadcrumbs are floating in the packaging of a breaded food product intended for oven cooking then that excess slack could end up burning on to the oven tray. Moreover, high quantities of slack can prevent products from being effectively packaged.

For example, in some cases a mixture of product and slack is dropped into packaging (e.g. an open bag) which is subsequently sealed towards its upper end. If slack falls at a slower rate than the product, slack may be trapped within the seal of the packaging. This may degrade the quality of the seal and allow ambient gases to penetrate the package, compromising the freshness of the food product. Hence excessive levels of slack can degrade the quality of the final packaged quality. This issue can occur (for instance) when the product is a jelly sweet or candy and the slack is a sugar coating packaged using a bag maker such as a vertical form fill seal (VFFS) machine. The sealing step can be delayed to allow the slack to settle before sealing so as to reduce the occurrence of this problem, but this approach does not entirely remove the problem and slows processing speed, reducing output of packaged products.

Excess slack may also collect in or adhere to product handling machinery. This may result in the machinery jamming. Equally, where the product is a food product, slack which is stuck in machinery for long periods may spoil or attract pests, thereby causing potential dangers to public health.

Therefore, excessive levels of slack contribute to a variety of issues when handling and packaging products, especially food products.

These problems are exacerbated in some cases because it may be necessary to introduce higher levels of slack into a product stream than is desired in the final packaged product. For instance, during coating processes for coated food products relatively large quantities of slack may be introduced into a product stream to ensure an even coating on each product. However, the excess slack which does not adhere to or coat the product will remain in the product stream as slack after the coating process is complete. Moreover, coating which is only loosely adhered to a coated product may easily fall off the product and create further slack downstream of the coating process. In view of the problems discussed above, it is desirable to separate this excess slack from the coated food product after the coating process.

Therefore, there is a need for an alternative method and/or apparatus for separating excess slack from product streams, which preferably contributes to solving one or more of the problems discussed above.

SUMMARY

The claimed invention provides improved devices, systems and methods for removing slack from a product stream. As discussed above, slack will be understood herein as comprising either a liquid, or a solid with dimensions that are significantly smaller than the product with which it is mixed (e.g. having an average dimension that is at least five or ten times smaller than the average dimension of the product).

One option for separating slack from a mixture of product and slack is to provide a grate or mesh in the surface of a conveyor. The mesh/grate comprises a series of apertures; the apertures being sized such that the product may not pass therethrough, whereas slack may pass through the apertures. As the mixture passes along the conveyor and over the mesh/grate, a portion of the slack in the mixture falls through the apertures, whilst continues along the conveyor. In this way the slack which passes through the apertures is separated from the mixture (i.e. from the product stream).

However, these devices are only capable of separating a relatively small proportion of the slack out of the mixture. Only slack which is in contact with the surface of the conveyor will be removed as the mixture passes over the mesh/grate. Slack that is supported on top of a product stream or travelling within the bulk of the product stream (i.e. internally within the mixture) will not be removed.

The claimed invention provides improved devices, systems and methods for removing slack from a product stream or other mixture. As discussed above, slack will be understood as being either a liquid, or a solid with dimensions that are at least five or ten times smaller than the product with which it is mixed.

In accordance with an aspect of the invention there is provided a device for separating slack from a mixture of product and slack, the device comprising: a hollow drum, wherein the drum comprises a drum wall and one or more apertures which extend through the drum wall, wherein the apertures are sized such that slack but not product may pass therethrough; a rotation unit, the rotation unit configured to rotate the drum such that, in use, the contents of the drum are tumbled; and an actuation unit configured to, in use, convey the contents of the drum towards a discharge end of the drum.

Therefore, when a mixture of product and slack is introduced into the centre of the hollow drum, slack may exit the drum via the apertures in the drum wall whilst the product is retained within the drum. As such, the drum wall acts as a filter, allowing slack from the mixture to leave therethrough but not product.

However, if a drum were to be held at a constant angular orientation (i.e. if a drum is not rotated) only the slack which is adjacent or close to the drum wall will pass through the apertures and be removed from the mixture. Slack which is supported on top of the mixture or held within the bulk of the mixture cannot travel through the mixture to the apertures, and will not exit the drum. In other words, if a mixture of product and slack is introduced into a non-rotating drum having the apertures discussed above, slack will only be removed from a relatively shallow layer of the mixture close to the drum wall. This is analogous to the conveyors with meshes or grates described above.

The rotation unit may be a motor (e.g. an electric motor) or any other piece of equipment or means suitable to rotate the drum and its contents. By providing a rotation unit and by rotating the drum whilst a mixture of product and slack is contained inside the drum, the proportion of slack which can be removed is significantly increased.

This is because when the drum is rotated the contents of in the drum will be tumbled by the rotation. The term tumbled is understood as meaning that different layers of the contents are mixed or blended together. As such, when a mixture of slack and product is within the drum, the slack and product in contact with the drum wall will be carried up the side of the drum as the drum rotates, until gravity causes this product and slack to fall back to the bottom of the drum to mix with the remaining contents of the drum. Rotation of the drum acts to blend or churn a mixture of slack and product within the drum, such that different layers and portions of the mixture are mixed together.

As the drum is rotated and the mixture within the drum is tumbled the portion of product and slack adjacent or close to the drum wall will continually change. Thus, a much greater proportion of the slack within the mixture is brought into contact with or close to the side wall of the drum during the tumbling. Therefore, a much greater proportion of slack is exposed the apertures, and a much greater proportion of slack can be removed from the mixture via the apertures.

Therefore it will be seen that devices in accordance with the invention are very successful at removing slack from a mixture of product and slack. This may improve the quality of a final packaged product (e.g. by removing trapped slack from inside the packaging and improve the quality of seals in the package) and reduce the cleaning and maintenance costs of downstream equipment.

Thus it will be seen that using devices in accordance with the invention slack may be quickly and efficiently sifted out of a mixture which is introduced into the drum when the drum is rotated by the rotation means. By reducing the amount of slack in the mixture claimed invention can improve the quality of packaged products (e.g. by reducing the proportion of slack in a packaged product, and avoiding poor package seals) and increase the output of a production system (e.g. by avoiding machinery jams and reducing the need for inspection and maintenance, and by avoiding settling time required when packaging products).

Moreover, devices in accordance with the invention offer further benefits when used with coated products. These coated products include coated food products such as sugared sweets, crisps and chips coated with flavourings, and breadcrumbed foods.

Handling coated products can create large amounts of slack. As the coated product is handled (e.g. by a piece of downstream machinery, or during transportation of the packaged product) loose coating on the surface of the product may be knocked off or dislodged to create undesirable slack.

By rotating a drum containing a coated product, any loose coating may be dislodged from the surface of the coated product as it is tumbled. This dislodged coating forms slack which may be immediately removed from the drum by the apertures in the drum wall. Hence, although the device generates slack the slack may be immediately removed from the product mixture.

Therefore, a mixture containing coated product which is discharged from the drum will both: (a) contain reduced levels of slack and (b) have reduced levels of loose coating on the surface of the products, such that handling the mixture downstream of the device will generate less slack. Hence, the level of slack present in the final packaged product may be greatly reduced.

Although tumbling products using the device generates sufficient forces to blend or mix the contents of the drum, and tumbling may dislodge loose coatings from the surfaces of coated products, these forces are typically not sufficient to cause any damage the products themselves. Therefore excess slack may be removed from a mixture of product and slack using devices in accordance with the invention without causing damage to the product.

Being hollow, the drum may comprise an internal volume or void such that the mixture of product and slack may be introduced into this internal volume.

The actuation unit allows for a product mixture with reduced levels of slack (and preferably no or negligible levels of excess slack) to be easily and consistently discharged from the drum. Thus a product stream may be automatically output from the discharge end of the drum for weighing, packaging or other downstream processes.

The actuation unit may be operated to motivate a mixture of product and slack within the drum to move longitudinally along the drum. As the mixture travels along the drum under the action of the actuation unit, slack within the mixture will encounter the aperture(s) in the drum wall and may be removed from the drum.

Consequently, product with reduced levels of slack may be output from the discharge end of the drum under the action of the actuation unit. The actuation unit may be configured to operate continuously or periodically, and in preferred examples is configured to operate simultaneously with the rotation unit so as to increase the proportion of slack that can be removed from the drum as the contents of the drum are simultaneously tumbled and conveyed longitudinally along the drum across the apertures in the drum wall.

The actuation unit may be configured to convey the contents of the drum directly (e.g. by physically contacting and pushing the drum contents through the drum) and/or indirectly (e.g. by causing the drum to move, such that forces are applied to the drum contents by the drum itself such that the drum contents are conveyed along the drum without direct contact between the actuation unit and the contents of the drum).

Preferably the rotation unit is configured to rotate the drum about a longitudinal axis of the drum. This is particularly preferred in embodiments in which the device is configured such that slack is removed from a mixture as is travels longitudinally through the drum.

Preferably the rotation unit is configured to rotate the drum by at least 90 degrees, more preferably at least 180 degrees, more preferably still by at least 360 degrees. For instance, the rotation unit may be configured to rotate the drum continuously or periodically in the clockwise and/or anticlockwise direction(s). Alternatively or additionally, the rotation unit may be configured to rotate the drum in a reciprocating or oscillatory manner such that the rotation unit alternately rotates the drum in clockwise and anticlockwise directions by (for instance) at least 90 or 180 degrees.

Preferably the rotation unit is configured to rotate the drum with a rotational speed from 10 rpm (revolutions per minute) to 30 rpm-i.e. from 1.05 rad/s to 3.14 rad/s. These figures are well suited for use with a wide variety of food products, and are especially suitable for use with sugared sweets and other coated food products.

However, other speeds may also be used. In further examples the rotation unit may be configured to rotate the drum at a rotational speed from 5 rpm (0.52 rad/s) to 60 rpm (6.28 rad/s).

In alternative examples the rotation unit may be configured to rotate the drum across alternative angular ranges and/or at alternative speeds to suit the specific mixture of product and slack within which the device is intended for use with. In further embodiments the rotation unit may also be configured to vary the speed of rotation and the direction of rotation to maximise the amount of slack which may be removed Preferably the drum comprises a substantially circular cross section. As such, the drum may be cylindrical or conical in form. A circular cross section minimises forces on the contents of the drum as the drum rotates. Therefore, the layers of the mixture may be blended or mixed without exposing the mixture to high forces which could damage the products or generate unexpected slack. Nevertheless, in further examples the drum may comprise a polygonal cross section. For instance, the drum may comprise an octagonal, hexagonal or square cross section. Similarly, in further examples the drum may comprise longitudinal fins or flutes which extend radially inwards from the drum wall. Varying the cross section of the drum may be used to modify the manner in which the contents of the drum are tumbled and thereby vary the forces applied to a mixture of product and slack as the drum is rotated.

The one or more apertures are holes or perforations which extend through the drum wall, forming opening(s) to the internal volume or void defined within the hollow drum. The one or more apertures are sized to separate slack from product -i.e. the apertures are sized such that slack but not product may pass through them. As such, the smallest dimension of each aperture may be greater than the largest dimension of a solid slack the device is intended for use with or sufficiently large to allow a liquid slack to flow therethrough, such that the slack may pass through said aperture. Additionally, the smallest dimension of each aperture may be smaller than the smallest dimension of the product the device is intended for use with, such that the product cannot pass through the aperture(s).

The minimum dimension (i.e. the smallest dimension) of each of the one or more apertures may be less than 1 cm, preferably less than 0.5 cm, and more preferably less than 0.25cm. For instance, the apertures may be circular with a dimeter of approximately 1 cm or elongate having a width of 1cm, but a length that is significantly larger. These apertures are appropriate for use with a large variety of products, including many food products. However, apertures with alternative dimensions are also possible.

The aperture(s) may be arranged in a wide variety of shapes and patterns. For instance, a plurality of apertures may be arranged in an irregular or regular array but this is not essential. The aperture(s) may be square, rectangular, circular, ovular or elongate, but many further options are possible. In some examples the drum may comprise a grill or mesh, such that the apertures are defined by the voids in the grill or mesh.

In examples where the drum comprises a plurality of apertures arranged in an array across the surface of the drum wall, preferably the array of apertures extends along at least 10% of the longitudinal length of the drum, preferably at least 20%, more preferably still at least 50%, more preferably still at least 65%.

Additionally or alternatively, the aperture(s) may extend through at least 10% of the drum wall (i.e. such that at least 10% of the drum wall is a void or gap defined by an aperture). More preferably apertures extend through at least 20% of the surface of the drum wall, more preferably at least 30%, more preferably still at least 40%. For instance, where a drum wall is formed by a mesh or grill a very high proportion of the surface drum wall will be missing since a mesh or grill comprises a large number of relatively large apertures.

Increasing the proportion of the drum through which apertures extend may increase the proportion of slack which can be separated from a mixture within the drum, whereas reducing the proportion of the drum through which apertures extend can increase the strength of the drum.

Preferably the discharge end of the drum is open, such that product may be discharged from the drum through the discharge end and/or an opposed end of the drum is open such that a mixture of product and slack may be introduced into 20 the drum through the opposed end.

For instance, the drum may comprise two opposed, open ends such that a product mixture containing a relatively large amount of slack may be introduced or fed into the drum at a first end (i.e. the input end) and a product mixture with relatively little slack may be output from the opposing second end (i.e. the discharge end) after the mixture has passed longitudinally through the rotating drum. It will be seen that such an embodiment can provide an efficient in-line process.

Alternatively, the drum may only comprise a single open end (i.e. the discharge 30 end) through which the drum may be fed and discharged. Such an embodiment may be well suited for batch processes.

In further embodiments the drum may comprise a cover or hatch configured to close an open end of the drum. For instance, a cover or hatch over an end of the drum may be opened to supply a mixture of product and slack to the drum and/or a cover or hatch over the discharge end of the drum may be opened to discharge product from the drum.

In some preferred examples the longitudinal axis of the drum is declined relative to the horizontal plane, the discharge end of the drum being arranged lower than an opposing end of the drum. Thus, in use the contents of the drum will tend to flow longitudinally along the drum towards the lower discharge end of the drum under gravity. For instance, in embodiments of declined drums having opposed input and discharge ends, a mixture of product and slack that is introduced to the drum at the higher, input end of the drum will tend to flow longitudinally along the drum towards the lower discharge end of the drum. This can increase the flow of specific combinations of product and slack through the drum.

Since the drum is continuously or periodically rotated by the rotation unit, a mixture of product and slack may flow through the drum even when the drum is arranged at relatively small angles of declination. For instance, the longitudinal axis of the drum may be declined relative to the horizontal plane be an angle from 0 to 20 degrees, preferably from 0 to 10 degrees, more preferably still from 0 to 5 degrees. The angle of declination may be selected to modify the speed at which a mixture progresses through the drum. This selection offers a method of controlling the dwell time of a mixture within the drum and the proportion of slack which is removed from the mixture as it passes through the drum.

Nevertheless, in further examples the drum may be arranged parallel to the horizontal. This may be suitable for combinations of product and slack for which the actuation unit (e.g. a drive unit as discussed below) alone is sufficient to convey the mixture of product and slack along the drum and/or if the device is intended to be used as a batch process in which product is retained in the drum for relatively long times (i.e. the dwell time within the drum is relatively high).

In particularly preferred examples the actuation unit comprises a drive unit, the drive unit configured to cause motion of the drum such that, in use, the contents of the drum are conveyed towards a discharge end of the drum. The drive unit is configured to move (e.g. translate, vibrate and/or rotate) the drum, such that the contents of the drum flow or travel towards the discharge end of the drum.

Therefore, in examples of devices with an actuation unit that comprises a drive unit (e.g. where the drive unit is the actuation unit) the drive unit enables smooth and consistent discharge of a product stream with reduced levels of slack from the drum.

The drive unit may be configured to translate the drum in a variety of directions including (but not limited to): horizontal and/or vertical directions; directions parallel and/or perpendicular to the axis of rotation; and/or directions parallel and/or perpendicular to the longitudinal axis of the drum.

The motion of the drum created by the drive unit may be transferred or transmitted to the contents of the drum by the structure of the drum. Thus the contents of the drum may be motivated to travel longitudinally along the drum without direct contact from the drive unit. In other words, the drive unit conveys the contents of the drum indirectly, by applying or transferring forces to the drum rather than directly to the contents of the drum.

As the mixture travels along the drum under the action of the drive unit, slack may be removed from the mixture via the aperture(s) in the drum wall. Consequently, product with reduced levels of slack may be discharged or output from the discharge end of the drum.

Preferably the drive unit is positioned outside the drum rather than internally within the drum. By avoiding components inside the drum (i.e. within the internal volume of the drum), slack and/or product is less likely to build up and create a jam or clog since there are fewer internal components (and preferably no internal components) against which the slack can gather. Therefore maintenance and cleaning of the drum may be reduced. For similar reasons, the rotation unit may be provided outside of the drum (although this is again not essential).

Preferably the rotation unit and the drive unit are configured to operate simultaneously. As such, the drum may be rotated by the rotation unit and driven by the drive unit at the same time. Whereas, in further examples the rotation unit and drive unit may be configured to operate alternately (e.g. such that the contents of the drum are tumbled for a predetermined duration, and then the contents are conveyed along the drum for a predetermined distance or time).

Operating the rotation unit and the drive unit simultaneously may offer particular benefits when the device is used as part of an in-line process. The drum may be continuously fed with a mixture of product and slack at an input end by a feed device and continuously output a mixture with reduced levels of slack from an opposing discharge end. This slack removal process can occur automatically without interaction from an operator or other machinery. Therefore devices in accordance with the invention may be configured to remove slack from a product stream without interrupting the normal operation of any upstream or downstream machinery.

However, additionally or alternatively, the rotation unit and drive unit may be configured to operate alternately (i.e. in turn). For instance, within a batch process the drum may be periodically loaded with a mixture of product and slack and rotated using the rotation unit to remove excess slack from the drum.

Subsequently, the rotation of the drum may be stopped (e.g. once predetermined time has elapsed, or once the weight of the contents of the drum has changed by a predetermined amount) and the drive unit may be operated to convey the remaining contents of the drum towards the discharge end of the drum such that the remaining contents with reduced levels of slack may be output or discharged.

In preferred examples the actuation unit comprises a vibration drive unit configured to vibrate the drum. Therefore, a mixture introduced into the hollow drum may be automatically conveyed longitudinally through the drum by operating the vibration drive unit.

The vibration drive unit (e.g. a motor or other vibration means) may be configured to vertically and/or longitudinally vibrate the drum. Such vibrations have been found to be particularly successful at conveying or transferring mixtures of product and slack along the drum. However, a vibration drive unit that is configured to provide alternative vibrations may also be used.

For many products, including food products, the vibration drive unit may be configured to vertically vibrate with an amplitude of from 0.1 mm to 5 mm, and with a frequency of from 10 Hz to 60 Hz However, alternative vibration parameters may also be used.

In further examples the actuation unit comprises a reciprocating drive unit configured to reciprocally move the drum along an axis that extends towards the discharge end of the drum from an opposing end of the drum; wherein the movement of the drum in a forward direction extending towards the discharge end of the drum is slower than the movement of the drum in the reverse direction. As such it will be seen that these reciprocating drive units (e.g. a reciprocating motor or alternative means) apply a reciprocating or oscillatory motion to a drum along the longitudinal axis of the drum offer In these examples, during the relatively slow forward stroke (e.g. in a direction from an input end of a drum to the discharge end of a drum) a mixture contained in the drum is carried forward by the drum. The frictional force between the mixture and drum wall which supports the mixture causes the drum and mixture to move forward together.

In contrast, during the relatively quick backward stroke the drum applies significantly greater forces and acceleration to the mixture contained therein.

Consequently, the frictional forces between the drum and the mixture are overcome, and the mixture remains in place as the drum moves quickly backwards beneath the mixture. Therefore, during each cycle a mixture contained in the drum is conveyed a small distance longitudinally along the drum towards the discharge end of the drum.

The axis along which the reciprocating drive unit reciprocally moves the drum (i.e. the axis that extends from the discharge end of the drum towards the opposing or input end of the drum) may be parallel to or substantially parallel to the longitudinal axis of the drum. However, this is not essential, and in some cases the reciprocating drive unit may be configured to reciprocally drive a drum that is declined relative to the horizontal (i.e. such that the longitudinal axis of the drum is angled relative to the horizontal) along a horizontal axis. In these cases a mixture of product and slack may flow consistently and easily from the input end of the drum towards the discharge end of the drum under the action of both gravity and the drive unit.

Although in some cases a reciprocating drive unit may also apply relatively small vertical motions or vibration to the drum (when compared to the longitudinal movement), reciprocating drive units offer the benefit that the contents of the drum may be conveyed along the drum without applying significant forces perpendicular to the direction in which the contents travel -e.g. without large vertical forces. By avoiding large vertical forces during the horizontal (or substantially horizontal) movement of the contents of the drum, damage to product within the drum may be reduced and creation of unnecessary additional slack may be avoided.

Suitable reciprocating drive units include the drive units produced for use in horizontal motion conveyors (also termed differential impulse conveyors). For instance, suitable drive units are produced by Heat and Control, Inc. as part of the horizontal motion conveyors sold under the tradename FastBack (RTM).

The vibration drive unit and reciprocating drive unit discussed above are particularly successful at conveying a mixture of product and slack along the drum when the drum is angled downwards (i.e. declined) relative to the horizontal. In these cases the mixture may travel smoothly along the sloped or angled drum as the drum is driven. As such, a mixture of product and slack introduced to the drum (e.g. at an input end of the drum) can flow consistently and predictably to the discharge end of the drum.

Preferably the drive unit and the rotation unit are configured to operate simultaneously, such that slack may be removed from a mixture of product and slack as the mixture is conveyed along the drum. As such, the rotation unit and the vibration drive unit and/or reciprocating drive unit may be configured to operate simultaneously.

In some examples the actuation unit may comprise a contact portion configured to, in use, push the contents of the drum towards the discharge end of the drum. Such contact portions may directly contact the contents of the drum to push or propel the drum contents longitudinally along the drum.

Actuation units with contact portions offer a simple and efficient means of outputting a product stream with reduced levels of slack (and in some cases negligible amounts of slack or no slack) from the discharge end of the drum.

However, contact portions that are provided internally within the drum and/or that are configured to enter the internal volume of the drum can, for some combinations of product and slack, increase the build-up or accumulation of slack within the drum. Therefore, depending on the combination of the product and slack in question, the maintenance and/or cleaning requirements for devices with contact portions may be increased when compared to devices comprising the drive units discussed above.

The contact portion may comprise: a helical surface configured to rotate about a longitudinal axis of the drum; a piston configured to move along the longitudinal axis of the drum; or one or more fins that extend radially inwards from the drum wall, wherein each fin is angled relative to the longitudinal axis of the drum such that the circumferential position of the fin varies along the length of the drum and wherein each fin is configured to rotate about the longitudinal axis of the drum.

Nevertheless, the contact portion is not limited to the forms discussed above and a variety of alternative contact portions are equally suitable. In some examples the actuation unit may comprise a plurality of contact portions. For instance, the actuation unit may comprise a plurality of helical surfaces (e.g. arranged as a double or triple helix) or a plurality of pistons.

In the case of a helical surface the drum may act as an Archimedes screw, such that a mixture of product and slack is conveyed or pushed along the drum by the rotating helical (e.g. screw-shaped) surface. This helical surface may be fixed relative to the drum, such that the rotation unit is configured to rotate both the drum and the helical surface. In these examples, in use (i.e. during the operation of the rotation unit), the contents of the drum may be simultaneously tumbled and conveyed towards the discharge end of the drum as the drum and helical surface are rotated. However, in further examples, the helical (i.e. screw-shaped) surface may be configured to rotate independently from the drum and may be rotated by a further component (e.g. a separate helical surface rotation unit such as an electrical motor).

Similarly, where the device comprises one or more angled fins, the fin(s) may be fixed relative to the drum (such that the rotation unit is configured to rotate the drum and the fin(s) simultaneously) or the fin(s) may be configured to rotate independently from the drum. In use, as the angled fin(s) rotate the contents of the drum may be pushed (i.e. propelled or conveyed) towards a discharge end of the drum.

In examples that comprise pistons, the pistons are configured to move longitudinally through the drum, pushing any drum contents ahead of them towards the discharge end of the drum. For instance, a piston may be configured to move periodically through the drum so as to expel or discharge the contents of the drum. During operation of the device a mixture of product and slack introduced into the drum may be tumbled to remove slack from the mixture before the piston is operated to output the remaining mixture from the discharge end of the drum. Thus, embodiments which comprise a piston are well suited for use as part of a batch process, whereas helical surfaces and fins may be preferred for use in in-line processes.

In some embodiments the actuation unit may comprise a drive unit and one or more contact portions. For instance, the device may comprise a reciprocating or vibration drive unit and a helical surface or angled fin configured to rotate about the longitudinal axis of the drum. However, this is not essential and in further embodiments the actuation unit may solely comprise a drive unit -i.e. such that the actuation unit is a drive unit configured to cause motion of the drum such that, in use, the contents of the drum are conveyed towards a discharge end of the drum -such as the vibration or reciprocating drive units discussed above.

In particularly preferred examples the device further comprises a slack collection reservoir configured to receive slack which has passed through the one or more apertures. This slack collection reservoir may store the separated slack, preventing the slack from re-entering the production line. The excess slack collected by the slack collection reservoir may be removed for disposal or preferably recycled or returned to an earlier stage in the production line. Therefore, a slack collection reservoir may help avoid unnecessary waste.

Alternatively, the separated slack may not be collected or contained after it passes through the apertures, and could instead be collected periodically from the ground or another surface beneath the drum. However, in these cases care should be taken to ensure that the separated slack does not unexpectedly or accidentally re-enter the production line.

Where the device comprises a single slack collection reservoir the length of the slack collection reservoir (as defined along the longitudinal axis of the drum) is preferably greater than the length drum wall (again in the longitudinal direction) over which apertures are provided. Hence slack which passes out of any aperture may enter the slack collection reservoir.

Alternatively, the device may comprise a plurality of slack collection reservoirs that are each arranged to receive slack which has passed through a respective subset of the one or more apertures. As such different apertures of the one or more apertures in the drum will feed different slack collection reservoirs.

Preferably the slack collection reservoir comprises an extraction point, wherein slack received in the slack collection reservoir may exit the slack collection reservoir via the extraction point. Thus, after slack has entered a slack collection reservoir via the one or more apertures, it may be removed through a separate extraction point, thereby emptying the slack collection reservoir. As such, slack may be removed from the slack collection reservoir in situ -i.e. without moving the slack receiving container relative to the dispersion table, or moving the drum or the slack removal device relative to other upstream or downstream machinery. This avoids any interruption of the operation of the device when collecting and removing slack.

Most preferably there is provided a single slack collection reservoir, with a single extraction point. This minimises the space required for the storage and removal of slack, and simplifies the removal and collection of slack. However, as mentioned above, the drum may alternatively comprise a plurality of slack collection reservoir each comprising one or more extraction points.

The extraction point(s) may be openings that extend through a wall of the slack collection reservoir(s). Alternatively, where the slack collection reservoir is a shroud the extraction point may be defined by an open end of the shroud. The extraction point(s) are preferably located in or near a base surface of the slack collection reservoir and/or at or near the lowest point of the collection reservoir container when in use. Therefore, substantially all of the slack within the slack collection reservoir may be drained or removed from the container quickly and easily with the aid of gravity which may cause the slack to flow towards the lowest point of the slack collection reservoir.

Extraction points offer a convenient means of removing slack from slack collection reservoir. Slack may be removed whilst the slack collection reservoir remains in place. However, in alternative embodiments, emptying a slack collection reservoir could involve separating the slack collection reservoir from the device.

Preferably a wall of the slack collection reservoir is declined towards the extraction point, such that slack received in the slack collection reservoir tends to flow towards the extraction point under gravity. As such, slack may tend to empty or drain from the slack collection reservoir under gravity and without, for instance, human interaction. In particularly preferred embodiments the slack collection reservoir comprises a base surface and an extraction point, wherein the base surface is angled towards the extraction point such that slack collects toward the extraction point.

Additionally or alternatively, the device may comprise a vacuum pump connected to the extraction point, the vacuum pump configured to remove slack from the slack collection reservoir. Therefore slack may be removed or emptied from the slack collection reservoir under suction provided by the vacuum pump. This may avoid the need for human interaction and reduce the operation requirements of the device.

The vacuum pump may be configured to operate continuously or periodically so as to prevent excessive accumulation of slack within the slack collection reservoir. In embodiments having multiple slack collection reservoirs a vacuum pump may be connected to each extraction point such that all slack receiving containers may be emptied automatically.

Alternatively or additionally, the extraction point may be closed with a plug or gate. The plug or gate may be opened periodically (e.g. automatically or by hand) such that slack may be removed from the slack receiving container.

In particularly preferred embodiments the slack collection reservoir is a shroud arranged concentrically around the drum. As such, the drum may be surrounded by the shroud in all radial directions, such that any slack that exits the drum radially via the apertures will be retained by the shroud. The shroud is preferably greater in length in its longitudinal direction than the portion of the drum over which apertures are arranged, and may have a similar length in the longitudinal direction as the drum.

An extraction point, from which slack may be removed from the shroud, may be defined by an open end of the shroud and/or be defined by an opening that extends through a side wall of the shroud. In particularly preferred examples the shroud may be have the shape of a frustum (i.e. a truncated cone or pyramid). In these cases the diameter or width of the shroud increases along the longitudinal length of the shroud and the wall of the shroud may be angled relative to the horizontal such that slack collected by the shroud may flow longitudinally along the wall of the shroud under gravity towards an extraction point (e.g. an open end of the shroud).

Where the slack collection reservoir is a shroud that surrounds the drum it is particularly preferred that the shroud may be removed from the device. For instance, the shroud may be configured to be detachably coupled to the drum (e.g. using clamps or bolts). This may allow an operator to access the drum and/or may allow cleaning and maintenance of the shroud and drum.

As an alternative to a shroud, the slack collection reservoir may comprise a container that directly underlies the drum in use, wherein the container comprises an opening that faces towards the drum. Thus slack which passes through the apertures of the drum may fall under gravity through the opening and into the container. To simplify removal of slack from the container, the container may comprise an extraction point provided close to or in a base of the container and the base (and/or any other walls of the container) may be angled towards the extraction point.

Advantageously the slack collection reservoir may be fixed or configured to be fixed relative to the drum. As such, a sack collection reservoir that is fixed relative to the drum may not move and/or rotate relative to the drum. For example, the slack collection reservoir may be permanently coupled to the drum (e.g. by adhesive or welding) or detachably coupled to the drum (e.g. by clamps, screws or bolts).

Therefore, the actions of the rotation unit and any drive unit may be applied to both the drum and the slack collection reservoir. For instance, forces applied to the drum by the rotation unit, and any drive unit (e.g. vibration drive unit, reciprocating drive unit, or any other drive unit) may be transmitted to the slack collection reservoir whilst the slack collection reservoir is fixed to the drum (and vice versa).

Indeed, in preferred examples: the rotation unit is further configured to rotate the slack collection reservoir; and/or the actuation unit comprises a drive unit, the drive unit being configured to cause motion of the slack collection reservoir; such that, in use, the contents of the slack collection reservoir are conveyed towards the extraction point. For instance, operating the rotation unit to rotate the drum may also rotate an attached slack collection reservoir. Similarly, vibrating or reciprocally driving the drum using a vibration drive unit and/or reciprocating drive unit may cause a slack collection reservoir to respectively vibrate and/or move reciprocally.

In such embodiments, as the slack collection reservoir is rotated or motivated, slack contained within the slack collection reservoir may flow or be conveyed along the reservoir -e.g. to an extraction point. Therefore, slack may be easily collected and extracted from the device (e.g. for recycling, reuse or disposal) as slack is separated from a mixture of slack and product by the rotation of the drum. Maintenance and operational requirements associated with emptying the slack collection reservoir may therefore be reduced.

In these examples the rotation unit and/or the drive unit cause motion of the slack collection reservoir, and may cause the contents of the slack collection reservoir to travel through the slack collection reservoir without direct contact between the slack and the rotation unit and/or drive unit. However, this is not essential and in further embodiments additional or alternative components such as pistons or helical (i.e. screw-shaped) surfaces may be provided within the slack collection reservoir to convey slack (e.g. to an extraction point) via direct contact with the slack.

As discussed above, when the slack collection reservoir is fixed to the drum, the drum and the slack collection reservoir may rotate and translate together. For instance, forces applied to the drum by the rotation unit and the drive unit will be transmitted to the slack collection reservoir (and vice versa). As such a single rotation component (e.g. a single motor) may rotate both the drum and the slack collection reservoir and a single drive component (e.g. a single vibrating motor or reciprocating motor) may move or translate the drum. Such an arrangement, may simplify manufacture and maintenance of the device.

However, in further examples the rotation unit may comprise two separate rotation components (e.g. separate motors) configured to respectively rotate the drum and the slack collection reservoir. Equally, the drive unit may comprise a first drive component (e.g. a first vibrating and/or reciprocating motor) configured to cause the drum to move and a second drive component (e.g. a second vibrating and/or reciprocating motor) configured to cause the slack collection reservoir to move. Such an arrangement may minimise operational costs.

According to a further aspect of the invention there is provided a system 25 comprising a device in accordance with any of the examples and embodiments discussed above.

Preferably the system further comprises a feed device configured to supply a mixture of product and slack to the drum. Thus the drum may be positions at an exit or discharge point of the feed device. For example, the feed device may be a conveyor that supplies a mixture of product and slack to an input end of the drum. A wide variety of conveyors may be used for this purpose including belt conveyors, vibrating conveyors, or a reciprocating horizontal motion conveyor (e.g. as manufactured by Heat and Control, Inc. under the tradename FastBack (RTM)).

In some embodiments the feed device comprises a vibratory conveyor; wherein the actuation means comprises a vibration drive unit configured to vibrate the vibratory conveyor and the drum, such that in use a mixture of product and slack on the vibratory conveyor is conveyed along the vibratory conveyor towards the drum, and the contents of the drum are conveyed towards the discharge end of the drum. In other words the system comprises a vibration drive unit that is configured to drive both the drum and the vibratory conveyor.

To achieve this, the drum may be configured to be coupled or fixed to the vibratory conveyor, such that vibration applied by the vibration drive unit to any the vibratory conveyor is transmitted to the drum (and vice versa). Preferably the connection between a vibratory conveyor and the drum is non-permanent such that the drum may be removed (e.g. to clean or maintain the drum and/or feed conveyor), but this is not essential. Suitable non-permanent fixings include bolts and clamps. The vibratory conveyor may be declined or angled relative to the horizontal such that a mixture of product and slack may more easily flow along the conveyor.

Benefits of these embodiments include that the design, manufacture and maintenance of the system may be simplified as a single vibration component is configured to vibrate both the feed conveyor and the drum to convey a product stream across both the vibrating conveyor and the drum. This single vibration component may comprise any of the features of the vibration unit discussed above and offer corresponding benefits.

The vibration drive unit may be further configured to vibrate a shroud (or other slack collection reservoir). As such, the vibration drive unit may be configured to cause the contents of the slack collection reservoir to travel through the slack collection reservoir -e.g. to an extraction point. The slack collection reservoir may be fixed to or configured to be fixed to the drum and/or the vibratory conveyor.

For example, the vibration drive unit may comprise a single vibrating component (e.g. a single vibrating motor) configured to vibrate the drum, the surface of the vibratory conveyor and any slack collection unit. However, this is not essential.

In alternative equally preferred embodiments the feed device comprises a horizontal motion conveyor; wherein the actuation means comprises a reciprocating drive unit configured to reciprocally move the horizontal motion conveyor and the drum along an axis that extends from the input end of the drum towards a discharge end of the drum, such that in use a mixture of product and slack on the horizontal motion conveyor is conveyed along the horizontal conveyor towards the drum and the contents of the drum are conveyed towards the discharge end of the drum. Again this approach simplifies the manufacture and maintenance of the system, since the system comprises a single reciprocating drive unit that may be used to reciprocate or oscillate both the drum and the feed conveyor.

As discussed previously, such a reciprocating drive unit is preferably configured to move the drum and the surface of the feed conveyor relatively slowly on a forward stroke (i.e. towards the discharge end of the drum) such that the product stream is carried forward on the drum and conveyor, before moving relatively quickly on the reverse or backwards stroke such that the product stream remains in place as the drum and conveyor move beneath the stream. This reciprocating motion avoids significant vertical forces and can reduce the risk of damage to products on the conveyor and within the drum and thereby minimises the unnecessary creation of slack. Nevertheless, in some examples the reciprocating drive unit may be configured to apply a relatively small vertical motion or vibrations to the feed conveyor and/or the drum (when compared to the motion of the feed conveyor and/or the drum along the longitudinal axis of the drum and when compared to vertical vibrations that may be applied by a vibration drive unit) so to improve conveyance of product along the conveyor and through the drum.

In preferred examples, the drum may be configured to be coupled or fixed to the horizontal motion conveyor such that reciprocating motion applied by the reciprocating drive unit to the conveyor is transmitted or transferred to the drum (and vice versa). Preferably the connection or coupling between the horizontal motion conveyor and the drum is non-permanent such that the drum may be removed (e.g. to clean or maintain the drum and/or feed conveyor), but this is not essential. Suitable non-permanent fixings include bolts and clamps.

Additionally or alternatively, the reciprocating drive unit may be configured to drive a shroud or other slack collection reservoir in a reciprocating or oscillatory manner -e.g. so as to convey the contents of the slack collection reservoir to an extraction point. The slack collection reservoir may be fixed to or configured to be fixed to the drum and/or the horizontal motion conveyor For example, the reciprocating drive unit may comprise a single reciprocating component (e.g. a reciprocating motor) configured to vibrate the drum, the surface of the vibratory conveyor and any slack collection unit. However, this is not essential.

In preferred embodiments the system comprises a dispersion feeder, weighing device and/or a packaging machine configured to receive product discharged from drum.

For instance, a dispersion feeder, weighing device and/or packaging machine may be arranged to receive a product stream directly from a discharge end of the drum (e.g. the dispersion feeder, weighing device or packaging machine may be positioned beneath the discharge end of the drum). In alternative embodiments the system may comprise an output conveyor, the output conveyor configured to receive product discharged from the drum. In such cases a dispersion feeder, weighing device and/or packaging machine may receive product discharged from the drum via the output conveyor. In further examples the mixture discharged or output by the drum may be delivered to downstream equipment manually.

A dispersion feeder, a weighing device and a packaging machine are typically found in sequence within many food production lines (although this is not essential). A dispersion feeder is configured enable a product stream (e.g. a food product stream) to be divided into roughly equal portions. These roughly equal portions are collected (for instance in feeder troughs or weigh hoppers), and then may be weighed and combined by a weighing device to provide final product portions with highly accurate weights. These product portions created by the weighing device may then be discharged to a packaging machine for final packaging.

Appropriate dispersion feeders include vibrating and/or rotating dispersion tables. The weighing device may be a computer controlled weigher (COW), such as a combination weigher, multihead weigher, screw fed weigher, cut gate weigher, linear weigher, or mix weigher. The packaging machine may be a bag maker (e.g. such as a vertical form fill seal (VFFS) machine), tray sealer, cartoniser or thermoformer. These weighers and packaging machines are well suited for use with (for example) food products.

Each of the dispersion feeders, weighing devices and/or packaging machines (and any alternative or additional machinery downstream of the drum) will benefit from reduced levels of slack. Lower levels of slack may reduce maintenance requirements and will increase the quality of the final products produced in a production line (as discussed above).

In accordance with a further aspect of the invention there is provided a method for separating slack from a mixture of product and slack using any of the devices discussed above or any of the systems discussed above, the method comprising the steps of: introducing a mixture of product and slack into the drum; operating the actuation unit to convey the contents of the drum towards the discharge end of the drum; and rotating the drum so as to tumble the contents of the drum. These steps may be performed as part of either an in-line process or a batch process.

Operating the actuation unit may comprise operating a drive unit (such as the vibration drive unit or reciprocating drive unit discussed above) to move the drum. Additionally or alternatively, operating the actuation unit could comprise moving (e.g. rotating or translating) a contact portion to push the contents of the drum towards the discharge end of the drum (e.g. rotating a helical surface or angled fin(s) about a central axis of the drum or moving a piston longitudinally through the drum).

During an in-line process the initial mixture of product and slack may be continuously or periodically introduced to the drum through an input end of the drum (the input end of the drum being an open end opposed to the discharge end of the drum). Whereas, the tumbled product (and any remaining slack) will be output from the discharge end of the drum.

In contrast, as part of a batch process, the initial mixture of product and slack will be periodically introduced to the drum, which will then be rotated to tumble its contents and remove slack. In such examples the mixture of product and slack may be introduced through either end of the drum, or through a gate or hatch provided within the drum wall itself.

Preferably the method comprises the step of discharging product from the drum and subsequently: dispersing product discharged from the drum using a dispersion feeder; weighing product discharged from the drum using a weighing device; and/or packaging product discharged from the drum using a packaging machine. The features and operation of suitable dispersion feeders, weighing devices and packaging machines are discussed above.

For instance, the product may be discharged or output from the discharge end of the drum directly to the downstream equipment. However, alternatively, a batch of mixture may be removed periodically from the discharge end of the drum and transferred to a dispersion feeder, weighing device, packaging machine or an alternative piece of downstream machinery.

In many preferred examples very low or negligible amounts of slack are output with the product from the drum. For instance, the product stream discharged by the drum may comprise less than 5% slack by weight, more preferably less than 1% slack by weight, more preferably still less than 0.5% slack by weight, more preferably still less than 0.1% slack by weight.

However, removing all slack from a mixture may be impractical, undesirable or unnecessary. For example, for products such as marinated meats it may be desirable to only remove a portion of the slack (e.g. marinade) from the mixture of product and slack, such that a final packaged product still contains an appropriate or predetermined level of slack.

The mixture of product and slack within the drum may be tumbled within the drum for a predetermined period of time in order to remove a desired proportion of slack.

For instance the mixture may be tumbled to remove 50% of the slack from the mixture introduced into the drum, more preferably to remove 75% of the slack, more preferably still to remove 90% of the slack.

For a given drum and aperture arrangement, the dwell time of product within the drum -i.e. the maximum time a mixture of product and slack may be tumbled within the drum -may be controlled by (for instance) varying the drive parameters of the drive unit (e.g. the frequency and amplitude of vibration of a vibration drive unit, and/or the frequency and the speed of the forward and reverse strokes of the reciprocating drive unit), varying the rotation parameters of the rotation unit (e.g. the speed and direction of rotation) and varying the angle of declination of the drum. Thus, controlling the above parameters may affect the proportion of slack that is separated from the mixture by the drum. However, it will be appreciated that a wide variety of further parameters may also be varied to affect the proportion of slack removed by the method and to affect the throughput of the system.

Alternatively, as part of a batch process, after an initial batch of product and slack has been introduced or supplied to the drum, the drum may be rotated until the weight of the contents of the drum has been reduced by a predetermined amount or a predetermined proportion. Thus a predetermined weight or proportion of slack may be removed from the batch of mixture originally supplied to the drum.

Preferably the method further comprises the step of collecting the slack separated from the mixture. For instance, the slack may be collected in a slack collection reservoir such as a shroud as discussed above. The collected slack may subsequently be extracted (e.g. via an extraction point) and recycled or reintroduced back to a point in the product line upstream of the drum. For instance, excess coating (e.g. sugar, flavourings or breadcrumbs) which has been removed from a mixture containing a coated food product (e.g. sugared sweets, crisps or breaded products) can be returned to a coating machine upstream of the drum to be used coating subsequent products. Alternatively the collected slack may be disposed of or processed in an alternative manner.

Preferably the product is a food product, more preferably a coated food product.

Preferably the slack is either a liquid or a solid, wherein the slack comprises a liquid and/or a solid, wherein the largest dimension of each solid piece of slack is smaller than the smallest dimension of each individual product.. For instance, a solid slack may be a powder or particulate. In many cases the average dimension of a solid slack is typically significantly smaller (e.g. at least five times or at least ten times smaller) than the average dimension of the product.

The products handled in the methods discussed above may be sugared sweets, crisps or chips, breaded products, or marinated meats, in which case the slack may be excess sugar, flavourings, breadcrumbs and marinade, respectively.

These methods offer corresponding benefits to the device and systems discussed above. In particular, methods in accordance with the invention significantly reduces the amount of slack which passes downstream from the drum, thereby improving packaged product quality, reducing maintenance requirements and increasing product output.

Methods in accordance with the invention (which are preferably performed in-line) and the devices and systems discussed above may not interrupt the normal operation or maintenance of other equipment along a production line. As such, devices and systems in accordance with the invention may be easily retro-fit into existing systems and machinery.

BRIEF SUMMARY OF FIGURES

Embodiments of the invention will now be described with reference to the following 10 figures: Figures la to id show views of a system in accordance with an embodiment of the invention; Specifically, Figure la shows a perspective view of an embodiment of the system; Figure lb shows the reverse perspective view of this system; Figure 1 c shows a projection view of the system; and Figure 1 d shows a cross-section of the system; Figure 2 shows a schematic view of a further system in accordance with an embodiment of the invention, this further system incorporates a device in accordance with the invention; Figure 3 shows a schematic cross section of an exemplary drum and actuation unit suitable for use in accordance with an embodiment of the invention; Figures 4a and 4b show schematic cross sections of a further exemplary drum and actuation unit suitable for use in an embodiment of the invention.

DETAILED DESCRIPTION

Devices and systems in accordance with the invention quickly and effectively remove slack from a product stream such that a packaged product is of a higher quality.

The systems and devices discussed in detail below are particularly well suited for use with food products and can remove the slack from a mixture of coated food products (e.g. sugared sweets, favoured potato crisps or chips and marinated meats) and their corresponding slacks (sugar, flavouring and marinade, respectively). In each of these exemplary mixtures it will be appreciated that the slack is either a liquid or a particulate solid with dimensions that are significantly less than the corresponding product (e.g. where the average dimension of the slack is at least 5 or 10 times smaller than the average dimension of the product).

Figures la to 1d show a system 1 capable of reducing the levels of slack within a product stream or mixture that contains both product and slack. The system 1 is shown in perspective views in Figures la and 1 b, from the side in Figure 1 c and in cross section in Figure Id.

The system 1 comprises a slack separating device 10 coupled to a feed device 20. As will be seen, the slack separating device 10 comprises a drum 12, rotation unit 14, shroud 16 (an example of a slack collection reservoir), chute 17 and slack separating device supports 18. The feed device 20 comprises a horizontal motion conveyor 22, drive unit 24 and feed device supports 26. The system 1 is configured to simultaneously rotate the drum 12 and to reciprocally drive the drum 12 in a horizontal direction that is substantially parallel to the longitudinal drum axis.

The drum 12 is formed as a hollow cylinder (although other shapes are possible).

The drum 12 comprises a plurality of apertures 12a that extend through the side wall of the drum 12 (i.e. the apertures extend from an inner surface of the side wall of the drum 12 to an outer surface of the side wall of the drum 12). The apertures 12a are configured to allow the slack but not the product within the mixture for which the system is to be used to pass through the side wall of the drum 12.

The drum 12 comprises an empty internal volume into which a mixture of product and slack may be introduced, the internal volume being accessible via two open ends -an input end 12b at which a product stream or mixture with a relatively large proportion of slack may be received from the feed device 20, and a discharge end 12c from which a product stream or mixture with reduced levels of slack may be output. The drum 12 is rotationally symmetric about its longitudinal axis (marked with broken line in Figures 1c and 1d).

As seen most clearly in Figure 1d, the apertures 12a of the drum 12 are ovular in shape, are consistently sized and arranged in a regular array around the circumference of the drum 12. The array of apertures 12a extends across over 60% of the longitudinal length of the drum 12 (i.e. the distance from the input end 12b of the drum 12 to the output end 12c of the drum 12). Apertures 12a extend through approximately 25% of the surface of the drum wall (although in further examples apertures may extend through approximately 10% to 50% of the surface of the drum wall).

However, it should be noted that this arrangement is not essential and a wide variety of shapes and arrangements of apertures can be used in alternative 20 embodiments.

Each of the apertures 12a in the drum 12 is sized such that its smallest or minimum dimension is smaller than the smallest or minimum dimension of the product with which the system 1 is intended to be used. As such, the product may not pass through any of the apertures 12a and cannot exit the drum 12 through the external side wall of the drum 12.

In contrast, the minimum dimension of each aperture 12a is preferably sized such that: when intended for use with solid slack, the smallest dimension of each aperture 12a is greater than the greatest dimension of the solid slack (the slack being significantly smaller in size than the product); or when intended for use with liquid slack, the liquid slack may easily flow therethrough. Consequently, slack may pass through the apertures 12a and drain out of the drum 12.

The drum 12 is surrounded by and coupled to the shroud 16, the shroud 16 being arranged concentrically around the drum 12. Slack which passes through the apertures 12a in the drum 12 falls under gravity and is received and collected by the surrounding shroud 16 (i.e. the shroud 16 acts as a collection reservoir for separated slack).

The shroud 16 has a solid (i.e. continuous) outer wall and has the form of a truncated cone or frustum, having a larger diameter towards the feed end 12a of the drum 12 than towards the discharge end 12b of the drum 12. Thus slack which falls from the drum 12 collects at the bottom of the shroud 16 and may subsequently flow along the angled surface of the shroud 16 under gravity (i.e. towards the input end 12b of the shroud 16) until it is discharged from an extraction point 16a at the end of the shroud 16.

Slack discharged from the extraction point 16a of the shroud is collected by the chute 17 -an angled member that directs the slack away from the drum 12 and shroud 16 under gravity. From the chute 17 the separated slack may be stored and subsequently collected (e.g. in a container or reservoir (not shown)). This collected excess slack may then be reintroduced to the production cycle upstream to avoid waste. The collection may be performed manually or automatically (e.g. using a conveyor system).

The shroud 16 is clamped to the drum 12. This non-permanent fixing allows the shroud 16 to be easily removed from the device 10 (e.g. for cleaning or maintenance of the shroud 16 and/or drum 12). In further examples a variety of other permanent and non-permanent attachment methods may also be used.

Similarly, the chute 17 is non-permanently attached to the remaining components of the slack separating device 10 (e.g. using clamps or bolts) such that the chute 17 may be separated from the slack separating device 10 for cleaning or maintenance.

The rotation unit 14 is configured to rotate the drum 12 and the shroud 16 about the longitudinal axis of the drum 12 (illustrated by the broken line of Figure 1d). In this example the rotation unit 14 is an electric motor although other means of rotating the drum 12 and shroud 16 may also be used.

Rotating the drum 12 using the rotation unit 14 significantly increases the proportion of slack removed from a mixture using the slack separation device 1. As the drum 12 is rotated product and slack will be carried up the inner surface of the drum wall until gravity causes the product and slack to fall from the inner surface of the drum 12 and mix with the remaining contents of the product stream.

Therefore, the product and slack is tumbled or churned, such that different layers within the mixture are continually mixed together. Consequently, the portion of the mixture of product and slack which is in contact with the inner surface of the drum 12 is continually refreshed. Therefore, a high proportion of slack travelling through the drum 12 encounters and passes through the apertures 12a in the drum wall.

Rotating the drum 12 using the rotation unit 14 offers further benefits when used with coated products since loose coating may be dislodged from the products by the tumbling motion. This loose coating (which forms slack as it is separated from the product) may be immediately separated out of the mixture within the drum via apertures 12a. Thus the product stream discharged by the drum 12 has reduced levels of slack and will generate less slack as the coated product is subsequently handled (both during subsequent production processes and after packaging).

Rotating the shroud 16 using the rotation unit 14 improves the flow of separated slack along the angled surface of the shroud 16 towards the extraction point 16a and the chute 17. Thus a build-up of slack in the shroud 16 is prevented, reducing the need to clean or maintain the system 1.

The slack separating device 10 is supported by four slack separating device supports 18. However this is not essential and a wide variety of alternative support systems may be provided.

The drum 12 of the slack separating device 10 is fed by the feed device 20-i.e. a mixture of product and slack may be introduced to the drum 12 using the feed device 20. As discussed above, the feed device 20 comprises a horizontal motion conveyor 22 (i.e. a feed conveyor) driven by drive unit 24 (e.g. a reciprocating motor).

The horizontal motion conveyor 22 is configured to transport articles (such as a mixture of product and slack) that are placed on its surface 22a in a substantially horizontal direction towards the drum 12 (i.e. towards the discharge end 22c of the drum 12). Specifically, the drive unit 24 is a reciprocating drive unit configured to move the surface 22a of the horizontal motion conveyor 22 reciprocally in the horizontal plane via a plurality of drive arms 24a (although other means for coupling the surface 22a of the horizontal motion conveyor 22 to the drive unit 24 are possible).

In more detail, the drive unit 24 is configured to move the horizontal motion conveyor 22 slowly in its forward direction (i.e. in a direction towards the distal end 24b of the feed conveyor and towards the drum 12) before it returns to its original position at a relatively high speed in the opposite, reverse direction (i.e. in a direction away from the drum 12). These movements are substantially horizontal, parallel to the surface 22a of the horizontal motion conveyor 22. Consequently a mixture of product and slack on the surface 22a of the horizontal motion conveyor 22 will be moved slowly towards the drum 12 in the forward direction on the slow forward stroke, but will be left in place as the surface 22a of the horizontal motion conveyor 22 moves quickly backwards in the reverse direction away from the drum 12. With each repeating cycle, the horizontal motion conveyor 22 moves the mixture of product and slack slightly further towards the drum 12. This approach minimises the generation of slack when conveying the mixture as large vertical forces are avoided.

As most clearly seen from Figure 1d, the distal end 22b of the horizontal motion conveyor 22 extends into the input end 12b of the drum 12. Therefore, when a mixture of product and slack reaches the distal end 22b of the horizontal motion conveyor 22, the mixture will fall into the drum 12. Hence a mixture of product and slack may be introduced or fed into the drum 12 by the horizontal motion conveyor 22.

In addition, the drum 12, rotation unit 14 and the shroud 16 are coupled to the horizontal motion conveyor 22 such that forces applied to the surface 22a of the horizontal motion conveyor 22 by the drive unit 24 are transmitted to the drum 12 and the shroud 16. As such, when the drive unit 24 reciprocates or oscillates the surface 22a of the horizontal motion conveyor 22, the drive unit 24 will also move the drum 12, rotation unit 14 and the shroud 16 in a reciprocating manner.

Thus, a mixture of product and slack introduced into the drum 12 (e.g. by the horizontal motion conveyor 22) may be conveyed from the input end 12b of the drum 12 towards the discharge end 12c of the drum 12 by the reciprocating movement of the drum 12.

It will be seen that, the drive unit 24 which is configured to cause motion of the drum 12 to convey drum contents longitudinally along the drum 12 is an example of the actuation units discussed above. The drive unit 24 is configured to, in use, convey the contents of the drum 12 towards a discharge end 12c of the drum 12.

The rotation unit 14 is configured to rotate the drum 12 and the shroud 16 as they are reciprocally driven by the drive unit 24 (and as a corollary the drive unit 24 is configured to reciprocally drive the drum 12, shroud 16 and rotation unit as the drum 12 and shroud 16 rotate). Therefore, a large proportion of slack may be removed from a mixture within the drum 12 as the mixture travels along the drum 12.

Therefore, the system 1 discussed above may consistently receive a feed mixture containing product and a large proportion of slack to the horizontal motion conveyor 22 and output a mixture containing product and significantly lower proportion of slack from the discharge end 12c of the drum 12. Ideally the mixture output from the drum 12 has no slack, or very small or negligible levels of slack. However, in practice it may be difficult to entirely remove slack from a mixture.

The mixture output by the system 1 may be fed (i.e. delivered to) a variety of subsequent equipment such as dispersion feeders, weighing devices and packaging machines for further processing. The mixture may be discharged to this subsequent equipment directly or using an output conveyor equipment.

In modified versions of the system 1 shown in Figure 1 the flow of mixture along the drum 12 can be increased by declining the longitudinal axis of the drum 12 relative to the horizontal plane -e.g. by between 0 and 10 degrees, more preferably between 0 and 5 degrees (as shown by the broken line in Figure 1d). In such cases, the discharge end 12c of the drum will be lower than the input end 12b of the drum. Therefore a mixture will tend to travel longitudinally along the drum 12 under both the action of the drive unit 24 and rotation unit 14, and gravitational forces. Thus the flow of a mixture through the drum 12 may be controlled through the selection of an appropriate declination of the drum and/or selection of appropriate operational parameters for the rotation unit 14 and drive unit 24.

Preferably the drum 12, rotation unit 14 and the shroud 16 are non-permanently coupled to the horizontal motion conveyor 22, such that these components may be separated -e.g. for cleaning or maintenance.

Figure 2 shows schematically a wider system 100 which is capable of receiving a product stream that contains product and a large proportion of slack and producing packaged products with reduced levels of slack. The system 100 comprises a slack separating device 200. The slack separating device 200 is fed by a feed device 160 and outputs to a weighing device 170, which in turn feeds a packaging machine 180.

The slack separating device 200 comprises a drum 120, a rotation unit 140 (e.g. an electric motor) configured to rotate the drum 120 about the longitudinal axis of the drum 120 and a drive unit 150 configured to cause the drum to move (e.g. translate). As shown, the rotation unit 140 and drive unit 150 are located outside of the drum 120.

The drum 120 is hollow, such that it comprises (i.e. defines) an internal void that may receive a mixture of product and slack. The drum 120 further comprises a plurality of apertures 120a that extend through the outer drum wall 120d of the drum 120. The apertures 120a are elongate, arranged in an array having two columns and are sized such that slack but not product may pass therethrough. Therefore, the drum wall 120d acts as a filter, such that slack may pass through the drum wall 120d whilst product is retained in the drum 120. The array of apertures 120a extends across over 50% of the length of the drum 120, and over 25% of the surface of the drum wall 120d is formed as apertures 120a. Nevertheless, a wide variety of alternative aperture arrangements may be used in further embodiments.

Operating the rotation unit 140 to rotate the drum 120 increases the proportion of slack which can be removed from a mixture within the drum 120. As the drum 120 is rotated its contents are tumbled, such that layers of a mixture within the drum are mixed or blended together. Therefore, when a mixture of product and slack is within the rotating drum 120 the portion of the mixture which is close to or adjacent to the drum wall 120d is frequently refreshed. As such a high proportion of the slack within the mixture will encounter and pass through the apertures 120a in the drum 120 and be removed from the mixture. This includes slack which was initially supported on top of the mixture or within the bulk of the mixture when the mixture was introduced to the drum 120.

The drum 120 is cylindrical (although other shapes are possible) and comprises two open ends: an input end 120a and a discharge end 120c.

The drive unit 150 (which may be a vibration drive unit such as a vibrating motor, a reciprocating drive unit such as a reciprocating motor, or any other drive means) is configured to cause the drum 120 to move, such that the contents of the drum 120 (e.g. a mixture of product and slack) travel through the drum 120 from the input end 120b of the drum 120 towards the output end 120c of the drum 120. In other words, the motion of the drum 120 created by operation of the drive unit 150 is transferred by the drum 120 to its contents. The contents of the drum 120 may travel longitudinally along the drum 120 under the forces transferred via the drum 120, rather than directly from the drive unit 150. The drive unit 150 thus forms an actuation unit configured to, in use, convey the contents of the drum 120 towards a discharge end 120c of the drum 120.

The feed device 160 is configured to supply a mixture of product and slack to the input end 120b of the drum 120. The feed device 160 may be a conveyor (i.e. a feed conveyor) such as a belt conveyor, vibrating conveyor or horizontal motion conveyor.

The drum 120 is configured to supply a mixture containing product and reduced levels of slack from its discharge end 120c to the weighing device 170 and the packaging machine 180. The weighing device 170 may be a computer controlled weigher (CC), such as a combination weigher, multihead weigher, screw fed weigher, cut gate weigher, linear weigher, or mix weigher. The weighing device 180 is configured to receive the mixture of portion and reduced levels of slack from the drum 120 and to output accurate portions of product to the packaging machine 180. The packaging machine 180 may be a bag maker, tray sealer, cartoniser, thermoformer or other packaging machine. The packaging machine 180 is configured to receive the product portions from the weighing device 170, to package the product and to output a packaged product. In further examples the system may comprise a dispersion feeder (not shown). For instance, the weighing device 170 may comprise a dispersion feeder.

A method of operating the system 100 shown in Figure 2 will now be described. This discussion refers to the flows through the systems illustrated by the arrows labelled P + S, S, P and P in Figure 2.

During an initial step of the method a mixture of product and slack is received by the feed conveyor 160, as shown by arrow P + S. The product in this mixture may be a food product such as a coated food product (in which case the method may include a preceding step of applying a coating to a food product using a coating machine position upstream of the feed conveyor 160). The feed conveyor 160 delivers the mixture of product and slack to the slack separating device 200. The mixture of product and slack is thus introduced to the drum 120 at the input end 120b of the drum.

After the mixture of product and slack is introduced to the drum 120, the drum 120 is rotated using the rotation unit 140 and caused to move (e.g. vibrated, reciprocated or driven in an alternative fashion) by drive unit 150 Under the action of the drive unit 150, the mixture of product and slack travels longitudinally along the drum 120. As the mixture P + S travels through the drum 120, slack is separated from the mixture by the drum 120 since slack but not product may pass through the apertures 120a that extend through the external drum wall 120d. As mentioned above, a large proportion of excess slack may be removed from the mixture fed into the drum 120 since the drum contents are tumbled by the rotation unit 140. Under this tumbling action, slack which would otherwise be trapped on top of or within the bulk of the mixture of product and slack can still be removed.

The separated slack falls from the drum 120 under gravity as indicated by arrow S and may be collected -e.g. for reuse or recycling, including reintroduction back into the production line upstream of the system 100. This collection of the slack may be performed using a slack collection reservoir or other alternative equipment (not shown).

Product that has passed longitudinally through the drum 120 is output from the discharge end 120c of the drum 120 to the weighing device 170, as shown by arrow P. In practice small amounts of slack may still be discharged with the product from the drum 120 since it may be difficult or undesirable to eradicate all slack from a mixture, however, preferably no or negligible amounts of excess slack are discharged from the drum 120 to the weighing device 170.

It will be seen that the product is discharged directly to the weighing device 170. However, this is not essential and in further examples an output conveyor may receive the product output from the drum 120 and convey it to the weighing device (or alternative downstream equipment).

The weighing device 170 receives the product from the drum 120 of the slack separating device 200, weighs the product, and divides the product into product portions of a predetermined weight or weights. The weighing device 170 subsequently outputs the product portions to the packaging device 180.

The packaging device 180 receives the product portions from the weighing device 170 and packages the product e.g. into bags, trays, cartons or containers). The packaging device outputs a final packaged product (as shown by arrow P'). The packaged product, which contains less slack than could be achieved without use of the system 100, may subsequently be delivered to consumers.

Thanks to the reduction in slack passing to the weighing device 170 and packaging machine 180 It will be appreciated that not only is the final packaged product produced by the system 100 of increased quality (since the packaging contains less slack and may be more effectively sealed), but also the operational and maintenance requirements of the weighing device 170 and packaging machine 180 may be significantly reduced since less slack passes through the machinery downstream of the slack separating device 200.

As discussed above, although the slack separating device 200 shown in Figure 2 does not include a slack collection reservoir, such as reservoir may be provided to collect the slack separated using the drum. Moreover, the system 200 of Figure 2 could be modified by replacing the feed conveyor 160 and slack separating device 200 discussed above with the system 1 described above in reference to Figures 1a to 1d.

The specific systems 1, 100 discussed above are well suited for use in an in-line process (e.g. the method described above with reference to Figure 2) where a product stream continually flows through the systems 1, 100. However, this is not essential and the slack separating devices 10, 100 discussed above could equally be used as part of a batch process.

For instance, a batch or portion of a product mixture with high levels of slack could be periodically fed or introduced into one of the slack separating devices 10, 100, the respective rotation unit 14, 140 may then be operated to rotate the respective drum 12, 120 to separate slack from the batch of product mixture before the respective drive unit 24, 150 is operated to convey the remaining contents of the drum 12, 120 to the discharge end 12c, 120c of the drum 12, 120 such that the batch of tumbled contents -a product mixture with a low level of slack -may be discharged.

Further examples of devices suitable for separating slack from a mixture of product and slack will now be discussed with references to Figures 3, 4a and 4b. Specifically, these figures show assemblies 300, 400 suitable for use within slack separating devices. These assemblies 300, 400 incorporate actuation units comprising contact portions configured to, in use, push the contents of the drum longitudinally along the drum towards a discharge end.

Figure 3 shows in cross section an assembly 300 comprising a drum 320 with an internal screw assembly 340. Together the drum 320 and the screw sub-assembly 340 act as an Archimedes screw, and are configured to push drum contents longitudinally along the drum when the screw sub-assembly 340 is rotated. Thus, the assembly 300 is configured to, in use (i.e. when the drum 320 and screw sub-assembly 340 are each rotated about the longitudinal axis of the drum 320), simultaneously convey product longitudinally along the drum 320 and remove excess slack from a mixture of product and slack Individual products p are shown on Figure 3 to show their passage through the drum 320. The relatively small slack (which typically has dimensions that are at least an order of magnitude smaller than the each individual product p) is omitted for clarity.

The drum 320 is hollow, being bounded by the drum wall 320d, and defines an internal volume 320e which may be accessed by two open ends: an input end 320b; and an opposing discharge end 320c. As will be seen from Figure 3, the drum 320 comprises a plurality of apertures 320a (e.g. an array of apertures 320a) extending through the external drum wall 320d. Each aperture is sized such that slack but not product may pass therethrough -the greatest dimension of each aperture 320a being smaller than the smallest dimension of each individual product p. Within the internal volume 320e of the drum 320 is mounted a screw subassembly 340 comprising a central axle 340a and a continuous helical surface 340b. The central axle 340a extends along the longitudinal axis of the drum 320 (shown by the broken line). The helical surface 340b -i.e. a screw-shaped surface -extends helically around the central axle 340a and the longitudinal axis of the drum 320 from the input end 320b of the drum 320 to the discharge end 320c of the drum 320.

The screw sub-assembly 340 is fixed relative to the drum 320, such that the screw sub-assembly 340 and drum 320 may, in use, rotate together about their longitudinal axis. Preferably the screw sub-assembly 340 is preferably non-permanently or detachably coupled to the drum 320 such that the screw sub-assembly 340 and drum 320 may be separated (e.g. for cleaning or maintenance).

A flow of product and slack through the assembly 300 shown in Figure 3 during use is shown by arrows P + S, P and S, whilst the rotation of the drum 320 and screw sub-assembly 340 are illustrated by arrow Ri.

A mixture of product and slack may first be introduced into the drum 320 (i.e. into the internal volume 320e of the drum) via the input end 320b of the drum 320, as shown by arrow P + S. Subsequently, the assembly 300 is rotated as shown by arrow Pl. Under the rotation action the contents of the drum 320 are simultaneously tumbled and pushed or propelled longitudinally along the drum towards the discharge end 320c of the drum 320 by the helical surface 340b of the screw sub-assembly 320. Thus the helical surface 340b forms part of an actuation unit, being configured to contact and push (i.e. convey) the contents of the drum 320 towards the discharge 320b of the drum 320. Simultaneously, the rotation of the drum 320 tumbles the drum contents, refreshing the portion of any contents that are adjacent to or in contact with the internal surface of the drum wall 320d. Thus large proportions of slack will encounter and pass through the apertures 320a in the drum wall 320d. This slack will exit the drum 320, as shown by arrow S, being separated or filtered away from the product that remains within the drum 320.

Finally, product which reaches the discharge end 320c of the drum 320 will be propelled from the drum 320 by the helical surface 340b (as shown by arrow P). Thus the assembly 300 shown in Figure 3 will discharge a mixture with reduced levels of slack from the discharge end 320c of the drum 320 as the drum 320 and the screw sub-assembly 320 are rotated. In practice a mixture discharged from the drum 320 may still contain small levels of slack, however, in some cases preferably all or substantially all of the excess slack within the initial mixture will be removed via the apertures 320a.

As shown, the helical surface 340b is formed as a left-handed screw, such that the assembly 300 must be rotated in a clockwise direction when viewed from the input end 320b of the drum 320 to convey the drum contents towards the discharge end of the drum 320. However, this is not essential, and in alternative examples a helical surface may be formed as a right-handed screw and the assembly may be rotated in the anti-clockwise direction when viewed from the input end of a drum to drive the contents of the drum from the input end to the discharge end A slack separating device comprising the assembly 300 shown in Figure 3 may further comprise a rotation unit (not shown) configured to rotate the assembly 300 as discussed above. In further examples a slack separating device comprising the assembly 300 discussed above may further comprise a drive unit (e.g. a vibration drive unit) which may act in tandem with the screw sub-assembly 340 at conveying the drum contents through the drum 320 (i.e. such that the slack separating device comprises an actuation unit incorporating both the drive unit and the Archimedes Screw 340).

Slack separating devices and systems that incorporate the assembly 300 shown in Figure 3 may be configured to operate continuously -e.g. as part of an in-line process -during which an initial mixture of product and slack is continuously supplied to the drum 320 via the input end 320b, the assembly 300 is continuously rotated, and a mixture containing product and relatively less slack is continuously discharged from the output end 320c of the drum 320. However, this is not essential and a slack separating device incorporating the assembly 300 shown in Figure 3 may also be used as part of a batch process.

Figures 4a and 4b show a further assembly 400 suitable for use in a slack separating device in cross section. The assembly 400 comprises a drum 420 configured to separate slack from product, and a piston 440 configured to push the contents of the drum along the drum 420 longitudinally along the drum 420 and out of the discharge end of the drum 420.

The drum 420 comprises a plurality of apertures 420a (e.g. a regular array of apertures 42a) that extend through an external drum wall 420d of the drum 420. The apertures 420a are each sized such that slack but not product within the intended mixture of product and slack may pass therethrough. The drum 420 comprises an open discharge end 420c through which both a mixture of product and slack may be introduced into the drum 420 and product may be discharged from the drum 420. The opposing end 420b of the drum 420 is closed.

The piston 440 comprises a piston rod 440a that extends through the closed opposing end 420b of the drum 420 and a piston head 440b that positioned within the internal volume 420e of the drum 420. The piston rod 440a and piston head 440b are configured to move along the longitudinal axis of the drum 420 (indicated by the broken line through the drum 420). The dimensions of the piston head 420b are configured to closely match the internal dimensions of the drum 420 such that the piston head 420b may push or propel any contents of the drum 420 along the drum as the piston head 420b is moved through the drum 420.

The operation of the assembly 400 shown in Figures 4a and 4b within a slack separating device will now be discussed with reference to arrows P + S, P and S which represent flows of product and slack. In addition, individual products p are shown on Figure 4 to illustrate their movements within the drum 420. The relatively small slack (which typically has dimensions that are at least an order of magnitude smaller than the each individual product p) is omitted from the figure for clarity.

As an initial process step, whilst the piston 440 is in a first, retracted position (i.e. where the piston head 440b is adjacent to the closed end 420b of the drum 420, as shown in Figure 4a), a batch of a mixture of product and slack is introduced into the drum 420. The mixture is introduced into the drum 420 via the open discharge end 420c of the drum 420, as shown by arrow P + S. Subsequently, the drum 420 is rotated, R2, using a rotation unit (not shown). Consequently, the contents of the drum 420 are tumbled by the rotation action, such that a large proportion of the slack is removed from the drum 420 via the apertures 420a, as shown by arrow S. In contrast, the product which cannot pass through the apertures 420a will be retained in the drum 420. For instance, the drum 420 may be rotated for a pre-determined period of time and/or until a predetermined amount of slack has been removed from the drum 420. The drum 420 may be rotated in either direction, and/or in each direction alternately.

Thereafter, the remaining contents of the drum 420 are expelled from the drum 420 using the piston 420, as shown by flow P in Figure 4b. To expel the remaining drum contents, the piston 440 is moved to a second, extended position, in which the piston head 440b is adjacent to the open discharge end 420c of the drum 420 (shown in Figure 4b). As the piston 440 is moved between these positions the piston head 440b will push or drive any drum contents that are located ahead of it, expelling product from the discharge end 420c of the drum 420. Thus a slack separating device or system that comprises the assembly 400 shown in Figures 4a and 4b may discharge or output a mixture containing relatively low levels of slack in comparison to the mixture initially introduced into the drum. As part of this process the piston head 440b acts as a contact portion that, in use, contacts the contents of the drum 420 and pushes the drum contents towards the discharge end 420b of the drum 420.

In the example above, the drum 420 is free to rotate about the piston 440. However, this is not essential and in further examples a drum and a piston may be configured to rotate together; this may be necessary where, for instance, the drum has a polygonal cross section.

It will be appreciated that each of the assemblies 300, 400 shown in Figures 3 and 4 may be incorporated into wide variety of product handling devices and systems similar to those shown in Figures 1 and 2.

All of the devices, methods and systems discussed above are well suited for use with a wide variety of products including food products, and especially coated food products such as sugared sweets and breaded foodstuffs.

Claims

CLAIMS1. A device for separating slack from a mixture of product and slack, the device comprising: a hollow drum, wherein the drum comprises a drum wall and one or more apertures which extend through the drum wall, wherein the apertures are sized such that slack but not product may pass therethrough; a rotation unit, the rotation unit configured to rotate the drum such that, in use, the contents of the drum are tumbled; and an actuation unit configured to, in use, convey the contents of the drum towards a discharge end of the drum.
2. A device according to claim 1, wherein the rotation unit is configured to rotate the drum by at least 90 degrees, more preferably at least 180 degrees, more preferably still by at least 360 degrees.
3. A device according to any preceding claim, wherein the rotation unit is configured to rotate the drum with a rotational speed from 10 rpm to 30 rpm.
4. A device according to any preceding claim, wherein the drum comprises a substantially circular cross-section.
5. A device according to any preceding claim, wherein the minimum dimension of each of the one or more apertures is less than 1 cm, preferably less than 0.5 cm, and more preferably less than 0.25cm.
6. A device according to any preceding claim, wherein the discharge end of the drum is open, such that product may be discharged from the drum through the discharge end and/or an opposing end of the drum is open such that a mixture of product and slack may be introduced into the drum through the opposing end.
7. A device according to any preceding claim, wherein a longitudinal axis of the drum is declined relative to the horizontal plane, the discharge end of the drum being arranged lower than an opposing end of the drum.
8. A device according to any preceding claim, wherein the actuation unit comprises a drive unit, the drive unit configured to cause motion of the drum such that, in use, the contents of the drum are conveyed towards a discharge end of the drum.
9. A device according to claim 8, wherein the actuation unit comprises a vibration drive unit configured to vibrate the drum.
10. A device according to claim 9, wherein: the actuation unit comprises a reciprocating drive unit configured to reciprocally move the drum along an axis that extends towards the discharge end of the drum from an opposing end of the drum; and wherein the movement of the drum in a forward direction extending towards the discharge end of the drum is slower than the movement of the drum in the reverse direction.
11. A device according to any preceding claim, wherein the actuation unit comprises a contact portion configured to, in use, push the contents of the drum towards the discharge end of the drum.
12. A device according to claim 11, wherein the contact portion comprises: a helical surface configured to rotate about a longitudinal axis of the drum; a piston configured to move along the longitudinal axis of the drum; or one or more fins that extend radially inwards from the drum wall, wherein each fin is angled relative to the longitudinal axis of the drum such that the circumferential position of the fin varies along the length of the drum and wherein each fin is configured to rotate about the longitudinal axis of the drum.
13. A device according to any preceding claim, further comprising a slack collection reservoir configured to receive slack which has passed through the one or more apertures.
14. A device according to claim 13, wherein the slack collection reservoir comprises an extraction point, wherein slack received in the slack collection reservoir may exit the slack collection reservoir via the extraction point.
15. A device according to claim 14, wherein a wall of the slack collection reservoir is declined towards the extraction point, such that slack received in the slack collection reservoir tends to flow towards the extraction point under gravity.
16. A device according to any of claims 14 to 15, further comprising a vacuum pump connected to the extraction point, the vacuum pump configured to remove slack from the slack collection reservoir via the extraction point.
17. A device according to any of claims 13 to 16, wherein the slack collection reservoir is a shroud arranged concentrically around the drum.
18. A device according to any of claims 13 to 17, wherein the slack collection reservoir is fixed, or configured to be fixed relative to the drum.
19. A device according to any of claims 13 to 18, wherein: the rotation unit is further configured to rotate the slack collection reservoir; and/or the actuation unit comprises a drive unit, the drive unit being configured to cause motion of the slack collection reservoir; such that, in use, the contents of the slack collection reservoir are conveyed towards the extraction point.
20. A system comprising a device according to any proceeding claim.
21. A system according to claim 20, the system further comprising a feed device configured to supply a mixture of product and slack to the drum.
22. A system according to claim 21, wherein: the feed device comprises a vibratory conveyor; and wherein the actuation means comprises a vibration drive unit configured to vibrate the vibratory conveyor and the drum, such that in use a mixture of product and slack on the vibratory conveyor is conveyed along the vibratory conveyor towards the drum, and the contents of the drum are conveyed towards the discharge end of the drum.
23. A system according to claim 21, wherein: the feed device comprises a horizontal motion conveyor; and wherein the actuation means comprises a reciprocating drive unit configured to reciprocally move the horizontal motion conveyor and the drum along an axis that extends from the input end of the drum towards a discharge end of the drum, such that in use a mixture of product and slack on the horizontal motion conveyor is conveyed along the horizontal conveyor towards the drum and the contents of the drum are conveyed towards the discharge end of the drum.
24. A system according to any of claims 20 to 23, further comprising a dispersion feeder, weighing device and/or a packaging machine configured to receive product discharged from the drum.
25. A method for separating slack from a mixture of product and slack using the device according to any of claims 1 to 19 or a system according to any of claims 20 to 24, the method comprising the steps of: introducing a mixture of product and slack into the drum; operating the actuation unit to convey the contents of the drum towards 30 the discharge end of the drum; and rotating the drum so as to tumble the contents of the drum.
26. A method according to claim 25 further comprising: discharging product from the drum and subsequently: dispersing product discharged from the drum using a dispersion feeder weighing product discharged from the drum using a weighing device; and/or packaging product discharged from the drum using a packaging machine.
27. A method according to any of claims 25 to 26 comprising the further step of: collecting the slack separated from the mixture.
28. A method according to any of claims 25 to 27, wherein the product is a food product, preferably a coated food product. 15
29. A method according to any of claims 25 to 28, wherein the slack comprises a liquid and/or a solid, wherein the largest dimension of each solid piece of slack is smaller than the smallest dimension of each individual product.