APPARATUS AND METHOD FOR TREATING A SUBSTRATE WITH SOLID PARTICLES

The present disclosure relates to an apparatus that employs a multiplicity of solid particles in the treatment of substrates, particularly a substrate which is or comprises a textile. The present disclosure further relates to a method for the treatment of substrates with solid particles using the apparatus. The present disclosure further relates to components of the apparatus, in particular to the lifter of the apparatus. The present disclosure particularly relates to an apparatus, components thereof (in particular to the lifters) and a method suitable for cleaning of soiled substrates. The present disclosure further relates to a kit and method suitable for retrofitting or converting an apparatus into an apparatus according to the present disclosure.

Conventional methods for treating and cleaning of textiles and fabrics typically involve aqueous cleaning using large volumes of water. These methods generally involve aqueous submersion of fabrics followed by soil removal, aqueous soil suspension, and water rinsing. The use of solid particles to provide improvements in, and advantages over, these conventional methods is known in the art. For example PCT patent publication WO2007/128962 discloses a method for cleaning a soiled substrate using a multiplicity of solid particles. Other PCT patent publications which have related disclosures of cleaning methods include: WO2012/056252; W02014/006424; WO2015/004444; WO2014/147390; WO2014/147391 ; WO2014/06425; WO2012/035343 WO2012/167545; WO2011/098815; WO2011/064581 ; WO2010/094959; and WO2014/147389. These disclosures teach apparatus and methods for treating or cleaning a substrate which offers several advantages over conventional methods including: improved treating/cleaning performance, reduced water consumption, reduced consumption of detergent and other treatment agents, and better low temperature treating/cleaning (and thus more energy efficient treating/cleaning). Other patent applications, for instance WO2014/167358, WO2014/167359, WO2016/05118, WO/2016/055789 and WO2016/055788, teach the advantages provided by solid particles in other fields such as leather treatment and tanning.

It would be desirable to provide even better apparatus for treatment methods which involve the use of a multiplicity of solid particles. In particular, it would be desirable to improve the efficiency and reliability, to further reduce water consumption, to facilitate quieter operation, to improve fabric care, and/or to reduce the power consumption and costs (including capital costs and/or running costs) of the apparatus and the operation thereof. It would also be desirable to reduce the complexity of the apparatus and the number of moving components therein. Furthermore, it would also be desirable to retrofit a conventional apparatus so that it is suitable for operation with a multiplicity of solid particles.

The present Applicant’s pending PCT application PCT/GB2017/053815 discloses an apparatus in which solid particles are stored in a rotatable drum which further provides a plurality of dispensing flow path(s) for the solid particles to flow from the storage compartment(s) to the interior of the drum, and a plurality of collecting flow paths for the solid particles to flow from the interior of the drum to the storage compartment(s), such that the direction of flow between the storage compartment(s) and the interior of the drum is controlled by the direction of rotation of the drum.

The present inventors sought to provide further improvements to the apparatus. In particular, the present inventors sought to increase the rate of collection of solid particles from the interior of the drum. Furthermore, the present inventors sought to reduce the complexity of cycles of rotations needed in order to collect solid particles from the interior of the drum while also keeping substrate tangling to a minimum.

It is an object of the present invention to address one or more of the aforementioned problems.

According to a first aspect of the invention, there is provided an apparatus for use in the treatment of substrates with a solid particulate material, said apparatus comprising a housing having mounted therein a rotatably mounted drum having an inner surface and an end wall and access means for introducing said substrates into said drum, wherein

(a) said drum comprises storage means for storage of said solid particulate material; and

(b) said drum comprises a first collecting flow path to facilitate flow of said solid particulate material from the interior of said drum to said storage means when said drum rotates in a first collecting direction,

characterised in that said drum comprises a second collecting flow path to facilitate flow of said solid particulate material from the interior of said drum to said storage means when said drum rotates in a second collecting direction, wherein said second collecting direction is in the opposite rotational direction to said first collecting direction, and wherein said first collecting flow path and said second collecting flow path are different flow paths.

It will be appreciated that the term“in the opposite rotational direction” means that if the drum is rotating in a first collecting direction that is clockwise, then the second collecting direction is counter-clockwise. Similarly, if the second collecting direction is clockwise, then the first collecting direction is counter-clockwise.

The apparatus of the present invention can collect solid particulate material from the interior of the drum regardless of the direction in which the drum is rotated. As such, the apparatus of the present invention can enable a reduced number and/or less complex series of substrate treatment rotation cycles. In particular, when drum rotation direction is reversed in order to reduce or avoid tangling of substrates during treatment, collection of solid particulate material from the interior of the drum is still able to continue. In this way, the apparatus of the present invention is able to continually collect the solid particulate material from the interior of the drum.

The apparatus of the present invention can also dispense with, and preferably does not comprise, a further storage means which is not attached to or integral with the drum (for instance a sump for storage of solid particulate material, such as a sump located beneath the drum). Similarly, the apparatus can dispense with, and preferably does not comprise, a pump for circulating said solid particulate material between the storage means and the interior of the drum (i.e. from the storage means to the interior of the drum, and from the interior of the drum to the storage means). Preferably, the apparatus can dispense with, and preferably does not comprise, a pump for circulating said solid particulate material.

In addition, the amount of water used in the treatment of the substrates is reduced because water is not required to transport the solid particulate material around the apparatus. The apparatus and methods of the present invention therefore only require the water needed as the liquid medium in the treatment of the substrates, which provides a significant reduction in water consumption.

A further advantage of the storage means being located in the rotatable drum is that solid particulate material can be centrifugally dried, i.e. it can undergo one or more spin cycles to dry the particles. Centrifugal drying of the solid particulate material may be separate from or included in the operation of the apparatus to treat substrates. For instance, centrifugal drying may be effected concurrently with extraction step(s) for removing liquid medium, as described herein. Thus, the method described herein for treating a substrate optionally comprises the step of centrifugal drying of the solid particulate material. It will therefore be appreciated that an advantage of the present invention is the dry storage of the solid particulate material.

Preferably, the drum is configured to bias solid particulate material present inside the drum towards said first collecting apertures during rotation of the drum in said first collecting direction and/or towards said second collecting apertures during rotation of the drum in said second collecting direction.

It will be appreciated that the rate of flow of the solid particulate material between the interior of the drum and the storage means may also be controlled, additionally or alternatively, by varying the rate of rotation of the drum and/or by intermittently rotating the drum.

The apparatus is preferably a front-loading apparatus, with the access means disposed in the front of the apparatus. Preferably the access means is or comprises a door. It will be appreciated that the drum has an opening at the opposite

end of the drum to the end wall, suitably wherein the opening is aligned with the access means, and through which opening said substrates are introduced into said drum.

The rotatably mounted drum (also referred to herein as a rotatable drum) is preferably cylindrical, but other configurations are also envisaged, including for instance hexagonal drums.

Thus, the inner surface of the drum is preferably a cylindrical inner surface.

The inner surface of the drum is the surface of the inner wall(s) of the drum. The inner wall(s) of the drum is/are joined to the end wall of the drum at the juncture of the inner and end walls. Thus, the inner surface is the surface of the inner wall of the drum which is disposed around the rotational axis of the drum, i.e. substantially perpendicular to the end wall of the drum.

For a cylindrical drum, the axis of the cylindrical drum is preferably the rotational axis of the drum. More generally, the inner and end walls of the drum define a three-dimensional volume in which the end wall intersects the rotational axis of the drum, and preferably intersects said rotational axis in a substantially perpendicular manner, and wherein the inner wall(s) is/are disposed around the rotational axis, preferably wherein the inner walls are substantially parallel to the rotational axis.

The inner surface of the drum preferably comprises perforations which have dimensions smaller than the longest dimension of the solid particulate material so as to permit passage of fluids into and out of said drum but to prevent egress of said solid particulate material (which is the opposite of many prior art apparatus, in which both fluids and solid particulate material exit the drum via perforations in its inner surface). Preferably the housing of the apparatus is a tub which surrounds said drum, preferably wherein said tub and said drum are substantially concentric, preferably wherein the walls of said tub are unperforated but having disposed therein one or more inlets and/or one or more outlets suitable for passage of a liquid medium and/or one or more treatment formulation(s) into and out of the tub. Thus, the tub is suitably water-tight, permitting ingress and egress of the liquid medium and other liquid components only through pipes or ducting components.

Preferably, the drum is disposed in the apparatus such that the axis of the drum is substantially horizontal. In a preferred embodiment, the drum is disposed in the apparatus such that the axis of the drum is substantially horizontal during at least part of the operation of the apparatus, and preferably during the whole of the operation of the apparatus. The improved collection rate of the apparatus of the present invention provides significant improvement in the collection efficiency for apparatus in which the axis of the drum is substantially horizontal during operation.

In an alternative embodiment, the apparatus and/or drum (and particularly the drum) is tiltable, as is known in the art, such that the axis of the drum to the horizontal plane can be varied before, during or after the treatment of the substrates in the apparatus, and preferably during the treatment or portion thereof, and particularly during rotation of the drum in a collecting direction. Tilting may be effected by any suitable means, including for instance an air bag, hydraulic ram, pneumatic piston and/or electric motor. In this embodiment, the drum and/or apparatus is tiltable preferably such that the axis of the drum defines an angle a to the horizontal plane which is greater than 0 and less than about 10°. In this embodiment, the drum and/or apparatus is preferably configured to be tiltable such that the drum is inclined in a downwards direction from the front of the drum to the end wall of the drum during at least a part of said treatment, and particularly during rotation of the drum in a collecting direction. Thus, the apparatus is suitably configured such that for at least a part of said treatment (particularly during rotation of the drum in a collecting direction) the axis of the drum is tilted such that it defines an angle a to the horizontal plane which is greater than 0 and less than about 10° and such that the drum is inclined in a downwards direction from the front of the drum to the end wall of the drum.

Advantageously, during operation of the apparatus of the present invention, neither the drum nor the tub allows ingress or egress of the solid particulate material, which is retained by the drum throughout the treatment cycle by which substrates are treated in the apparatus. In other words, the solid particulate material remains in the storage means and/or in the interior of the drum and/or in the flow paths between the storage means and the interior of the drum throughout the treatment cycle, thereby obviating the need for a pump to circulate the particulate material and thereby obviating the need for a further storage means (such as a sump) which is not attached to or integral with the drum.

The apparatus preferably comprises a seal between the access means and the tub such that, in use, liquid medium is not able to exit the tub. Preferably, said seal is a door seal, as is conventional in the art. The seal between the access means and the tub prevents water leakage from the apparatus. The apparatus preferably further comprises a seal which prevents egress of the solid particulate material from the drum at the periphery thereof, in order to prevent egress of solid particulate material into the tub or egress of solid particulate material from the apparatus at the periphery of the access means, and such a seal is preferably disposed as a seal between the access means and the drum. Typically, said seal is made from foam or rubber or some other resiliently flexible material.

The apparatus further comprises the typical components present in apparatus suitable for the treatment of substrates with solid particulate material, preferably in a liquid medium and/or in combination with one or more treatment formulation(s) as described in more detail hereinbelow. Thus, the apparatus preferably comprises at least one pump for circulation of the liquid medium, and associated ports and/or piping and/or ducting for transport of the liquid medium and/or one or more treatment formulation(s) into the apparatus, into the drum, out of the drum, and out of the apparatus. Preferably, the apparatus comprises a suitable drive means to effect rotation of the drum, and suitably a drive shaft to effect rotation of the drum. Preferably, the apparatus comprises heating means for heating the liquid medium. Preferably, the apparatus comprises mixing means to mix the liquid medium with one or more treatment formulation(s). The apparatus may further comprise one or more spray means to apply a liquid medium and/or one or more treatment formulation(s) into the interior of the drum and onto the substrate during the treatment thereof.

The apparatus typically further comprises an external casing, which surrounds the tub and drum.

It will be appreciated that the apparatus suitably further comprises a control means programmed with instructions for the operation of the apparatus according to at least one treatment cycle. The apparatus suitably further comprises a user interface for interfacing with the control means and/or apparatus.

The apparatus preferably comprises said solid particulate material.

Typically, said drum has a first elongate protrusion located on said inner surface of said drum wherein said first elongate protrusion extends in a direction away from said end wall, wherein said first elongate protrusion has an end proximal to the end wall and an end distal to the end wall, wherein said first elongate protrusion comprises said first collecting flow path and further comprises a first collecting aperture, and wherein said first collecting aperture defines the start of said first collecting flow path.

Said first elongate protrusion located on the inner surface of the drum in the apparatus of the present invention is a type of“lifter”. Lifters are used in conventional apparatus, as well as in apparatus adapted for the treatment of substrates using solid particulate material, to encourage circulation and agitation of the contents (i.e. the substrate(s), treatment agents and solid particulate material) within the drum during rotation of the drum.

Typically, said first elongate protrusion is disposed on the inner surface of the drum such that the elongate dimension of the protrusion is essentially perpendicular to the direction of rotation of the drum.

Preferably, said first collecting aperture is disposed in a first side of said first elongate protrusion, wherein said first side of said first elongate protrusion is the leading side of said first elongate protrusion during rotation of the drum in said first collecting direction.

Said first elongate protrusion may comprise a plurality of said first collecting apertures disposed in said first side of said first elongate protrusion at a plurality of positions from the proximal end to the distal end thereof. Typically, there may be from about 2 to about 200, from about 3 to about 100, from about 4 to about 50, from about 5 to about 30, from about 6 to about 25, or from about 10 to about 20 first collecting apertures disposed on said first side of said first elongate protrusion. For domestic washing machines, preferably there are from about 5 to about 15 first collecting apertures disposed on said first side of said first elongate protrusion. For commercial substrate treatment machines, preferably there are from about 5 to about 100 first collecting apertures disposed on said first side of said first elongate protrusion.

Said first collecting aperture(s) may be any suitable size and shape to allow ingress of solid particulate material into said first collecting flow path. Typically, the shape of said first collecting aperture(s) is substantially rectangular, substantially circular, substantially square or substantially oval in shape. Preferably, the shape of said first collecting aperture(s) is substantially rectangular. Preferably, the first collecting aperture(s) is positioned in order that entry of said solid particulate material from the interior of said drum to the first collecting flow path is as free-flowing as possible. Preferably, the first collecting aperture(s) is adjacent the inner surface of said drum. Typically, said first elongate protrusion comprises an arrangement of a plurality of first collecting apertures such that substantially the entire length of the first side of said first elongate protrusion from the proximal end to the distal end comprises first collecting apertures. Preferably, each aperture is separated from its neighbour or neighbours by a distance of about 10 mm or less, about 8 mm or less, about 5 mm or less, about 3 mm or less or about 1 mm or less. Preferably, the first collecting apertures comprise from about 50 to about 95%, preferably from about 60 to about 90% of the length of the first side of said first elongate protrusion. Having an arrangement with a plurality of closely spaced first collecting apertures allows for efficient collection (also known as “harvesting”) of solid particulate material from the interior of said drum. In particular, such an arrangement advantageously increases the opportunities for solid particulate material in the interior of the drum to strike a first collecting aperture when the drum is rotated in said first collecting direction and thus allows for ingress of said solid particulate material into said first collecting flow path.

Preferably the first side of said first elongate protrusion is adapted to bias solid particulate material towards said first collecting aperture(s).

For instance, said first collecting aperture(s) may have a funnel shape to increase the cross-sectional area at the entry to said first collecting flow path and thereby increase the probability of entry of solid particulate material into said first collecting flow path.

Additionally or alternatively, the region between adjacent first collecting apertures may be angled towards a collecting aperture, thereby encouraging solid particulate material to enter the collecting flow path.

Optionally, said first elongate protrusion may comprise a collecting groove along at least part of said first side, wherein the collecting groove is configured to collect solid particulate material during rotation in said first collecting direction, whereupon the solid particulate material is biased towards said first collecting aperture(s) during further rotation in said first collecting direction. Such a collecting groove is preferably disposed in said first elongate protrusion along at least part of the edge of said first elongate protrusion where it meets the inner wall of the drum.

Preferably, said first elongate protrusion is configured to bias solid particulate material in said first collecting flow path towards the storage means during rotation of the drum in said first collecting direction. Preferably, said first elongate protrusion is further configured to prevent, more preferably to eliminate, solid particulate material present in said first

collecting flow path from returning to the interior of said drum when the drum rotates in said second collecting direction. For instance, said first elongate protrusion may comprise one or more flap, paddle, gate or combination thereof that adopts an open position that permits solid particulate material in the first collecting flow path moving towards the storage means when the drum is rotating in said first collecting direction but adopts a closed position that prevents solid particulate material from re-entering the interior of said drum when the drum is rotating in said second collecting direction.

More preferably, said first elongate protrusion is configured to bias solid particulate material in said first collecting flow path towards the storage means during rotation of the drum in both said first collecting direction and in said second collecting direction. In this way, solid particulate material that has entered said first collecting flow path is able to continue to move towards the storage means even when the direction of rotation of the drum is reversed. This arrangement significantly reduces, and preferably completely eliminates, the amount of solid particulate material that re-enters the interior of the drum from said first collecting flow path when the direction of rotation of the drum is reversed. For instance, said first elongate protrusion may comprise an arrangement of deflectors that urges solid particulate material towards the storage means regardless of the direction of rotation of said drum.

Said first elongate protrusion may comprise one or more curved surfaces, or“ramps”, adjacent to said first collecting apertures that urges solid particulate material somewhat radially inwards and more towards the central axis of rotation of the drum. Having a curved surface adjacent to a first collecting aperture can provide improved capture of the solid particulate material when the drum rotates at varying speeds. In addition, this arrangement helps prevent solid particulate material from exiting the first collecting apertures and re-entering the interior of said drum. Having a curved surface adjacent said first collecting apertures is particularly preferable where said first elongate protrusion comprises an arrangement of deflectors.

Bidirectional elongate protrusions

In a first preferred embodiment, said first elongate protrusion further comprises said second collecting flow path and a second collecting aperture, wherein said second collecting aperture defines the start of said second collecting flow path. In this arrangement, said first elongate protrusion comprises both said first collecting flow path and said second collecting flow path. In this way, said first elongate protrusion is able to collect solid particulate material regardless of the direction of rotation of the drum. As such, this arrangement of the first elongate protrusion may also be known as a“bidirectional elongate protrusion” or a“bidirectional lifter”.

Said second collecting aperture may be disposed in a second side of said first elongate protrusion, wherein said second side of said first elongate protrusion is the leading side of said first elongate protrusion during rotation of the drum in said second collecting direction.

Said first elongate protrusion may comprise a plurality of said second collecting apertures disposed in said second side of said first elongate protrusion at a plurality of positions from the proximal end to the distal end thereof. Typically, there may be from about 2 to about 200, from about 3 to about 100, from about 4 to about 50, from about 5 to about 30, from about 6 to about 25, or from about 10 to about 20 second collecting apertures disposed on said second side of said first elongate protrusion. For domestic washing machines, preferably there are from about 5 to about 15 second collecting apertures disposed on said second side of said first elongate protrusion. For commercial substrate treatment machines, preferably there are from about 5 to about 100 second collecting apertures disposed on said second side of said first elongate protrusion.

Said second collecting aperture(s) may be any suitable size and shape to allow ingress of solid particulate material into said second collecting flow path. Typically, the shape of said second collecting aperture(s) is substantially rectangular, substantially circular, substantially square or substantially oval in shape. Preferably, the shape of said second collecting aperture(s) is substantially rectangular. Preferably, the second collecting aperture(s) is positioned in order that entry of

said solid particulate material from the interior of said drum to the second collecting flow path is as free-flowing as possible. Preferably, the second collecting aperture(s) is adjacent the inner surface of said drum. Typically, said first elongate protrusion comprises an arrangement of a plurality of second collecting apertures such that substantially the entire length of the second side of said first elongate protrusion from the proximal end to the distal end comprises second collecting apertures. Preferably, each aperture is separated from its neighbour or neighbours by a distance of about 10 mm or less, about 8 mm or less, about 5 mm or less, about 3 mm or less or about 1 mm or less. Preferably, the second collecting apertures comprise from about 50 to about 95%, preferably from about 60 to about 90% of the length of the second side of said first elongate protrusion. Having an arrangement with a plurality of closely spaced second collecting apertures allows for efficient collection (also known as“harvesting”) of solid particulate material from the interior of said drum. In particular, such an arrangement advantageously increases the opportunities for solid particulate material in the interior of the drum to strike a second collecting aperture when the drum is rotated in said second colleting direction and thus allows for ingress of said solid particulate material into said second collecting flow path.

Preferably the second side of said first elongate protrusion is adapted to bias solid particulate material towards said second collecting aperture(s).

For instance, said second collecting aperture(s) may have a funnel shape to increase the cross-sectional area at the entry to said second collecting flow path and thereby increase the probability of entry of solid particulate material into said second collecting flow path.

Additionally or alternatively, the region between adjacent second collecting apertures may be angled towards a collecting aperture, thereby encouraging solid particulate material to enter said second collecting flow path.

Optionally, said first elongate protrusion may comprise a collecting groove along at least part of the second side, wherein the collecting groove is configured to collect solid particulate material during rotation in said second collecting direction, whereupon the solid particulate material is biased towards the second collecting aperture(s) during further rotation in said second collecting direction. Such a collecting groove is preferably disposed in said first elongate protrusion along at least part of the edge of said first elongate protrusion where it meets the inner wall of the drum.

Preferably, said first elongate protrusion is configured to bias solid particulate material in said second collecting flow path towards the storage means during rotation of the drum in said second collecting direction. Preferably, said first elongate protrusion is further configured to prevent, more preferably to eliminate, solid particulate material present in said second collecting flow path from returning to the interior of said drum when the drum rotates in said first collecting direction. For instance, said first elongate protrusion may comprise one or more flap, paddle, gate or combination thereof that adopts an open position that permits solid particulate material in said second collecting flow path moving towards the storage means when the drum is rotating in said second collecting direction but adopts a closed position that prevents solid particulate material from re-entering the interior of said drum when the drum is rotating in said first collecting direction.

More preferably, said first elongate protrusion is configured to bias solid particulate material in said second collecting flow path towards the storage means during rotation of the drum in both said first collecting direction and in said second collecting direction. In this way, solid particulate material that has entered said second collecting flow path is able to continue to move towards the storage means even when the direction of rotation of the drum is reversed. This arrangement significantly reduces, and preferably completely eliminates, the amount of solid particulate material that re-enters the interior of the drum from said second collecting flow path when the direction of rotation of the drum is reversed. For instance, said first elongate protrusion may comprise an arrangement of deflectors that urges solid particulate material towards the storage means regardless of the direction of rotation of said drum.

Said first elongate protrusion may comprise one or more curved surfaces, or“ramps”, adjacent to said second collecting apertures that urges solid particulate material somewhat radially inwards and more towards the central axis of rotation of the drum. Having a curved surface adjacent to a second collecting aperture can provide improved capture of the solid particulate material when the drum rotates at varying speeds. In addition, this arrangement helps prevent solid particulate material from exiting the second collecting apertures and re-entering the interior of said drum. Having a curved surface adjacent said second collecting apertures is particularly preferable where said first elongate protrusion comprises an arrangement of deflectors.

Typically, said first elongate protrusion is rectilinear in shape.

Preferably, said first collecting flow path and said second collecting flow path are symmetrically arranged along the length of said first elongate protrusion.

Preferably, said first elongate protrusion comprises a first lengthwise portion and a second lengthwise portion. Preferably, said first lengthwise portion and said second lengthwise portion are symmetrically arranged along the length of said first elongate protrusion.

Solid particulate material that is in the first collecting flow path is preferably urged along said first lengthwise portion towards said storage means as said drum rotates in said first collecting direction. Preferably, when said drum rotates in said second collecting direction, said solid particulate material in said first collecting flow path may transfer to said second lengthwise portion and be urged towards said storage means as said drum rotates in said second collecting direction. Similarly, solid particulate material that is in the second collecting flow path is preferably urged along said second lengthwise portion towards said storage means as said drum rotates in said second collecting direction. Preferably, when said drum rotates in said first collecting direction, said solid particulate material in said second collecting flow path may transfer to said first lengthwise portion and be urged towards said storage means as said drum rotates in said first collecting direction.

Preferably, said first elongate protrusion comprises a barrier projecting from a base portion of said first elongate protrusion adjacent the inner surface of said drum, wherein said barrier extends at least partially towards a top portion of said first elongate protrusion, wherein said barrier at least partially separates said first lengthwise portion from said second lengthwise portion. Solid particulate material that enters said first elongate protrusion by a first collecting aperture is urged to follow said first collecting flow path as the drum rotates, whereas solid particulate material that enters said first elongate protrusion by a second collecting aperture is urged to follow said second collecting flow path as the drum rotates.

The barrier may comprise a first barrier wall and a second barrier wall both projecting from a base portion of said first elongate protrusion adjacent the inner surface of said drum. Both the first barrier wall and the second barrier wall are spaced apart to define a central space therebetween. The first and second barrier walls may be arranged parallel to each other and may optionally be spaced apart by a third barrier wall. The central space may therefore be bounded by the first, second, third barrier wall and the base portion. Alternatively, the first and second barrier walls may be angled relative to each other such that they join with an apex positioned towards the centre of the drum. The central space may therefore be bounded by the first and second barrier walls and the base portion. The first and second collecting flow paths may be located on the external sides of the first and second barrier walls, i.e. the opposite sides of the barrier walls to the central space. Preferably, said barrier at least partially separates said first lengthwise portion from said second lengthwise portion. In arrangements where the first collecting flow path and/or the second collecting flow path comprises a series of deflectors, the deflectors in said first lengthwise portion may be connected to the first barrier wall and deflectors in said second lengthwise portion may be connected to the second barrier wall. Connecting the deflectors of said first and second lengthwise portion to separate first and second barrier walls may improve the ease of manufacture of the elongate protrusion.

Preferably, said first elongate protrusion is configured such that solid particulate material that is in the first collecting flow path is able to move over the top of said barrier into said second lengthwise portion when the drum changes rotation direction from said first collecting direction to said second collecting direction. Preferably, said first elongate protrusion is configured such that solid particulate material that is in the second collecting flow path is able to move over the top of said barrier into said first lengthwise portion when the drum changes rotation direction from said second collecting direction to said first collecting direction.

Preferably, said first side and/or said second side of said first elongate protrusion is inclined so that the width of said first elongate protrusion is narrower at a top portion of said first elongate protrusion than at a base portion of the elongate protrusion adjacent the inner surface of said drum.

The apparatus of the present invention preferably comprises a plurality of said first elongate protrusions. The drum preferably has from 2 to 10, preferably 2, 3, 4, 5 or 6 and preferably 2, 3 or 4, and preferably 3 or 4, of said first elongate protrusions. For domestic washing machines, 3 protrusions are most preferred. For commercial washing machines, 4, 5 or 6 protrusions, and preferably 6 protrusions, are most preferred. Where a plurality of first elongate protrusions are located on the inner surface of the drum, all of the elongate protrusions typically have the same or substantially the same dimensions as each other. In alternative embodiments, a plurality of first elongate protrusions may have elongate protrusions of differing dimensions, i.e. one or more elongate protrusions of a first size and/or shape, and one or more elongate protrusions of a second size and/or shape, etc.

As noted above, the first elongate protrusion is a type of“lifter”. As such, according to a second aspect of the invention, there is provided a lifter for use in a rotatably mounted drum of an apparatus for use in the treatment of substrates with a solid particulate material, the lifter comprising:

(a) an elongate body having a proximal end and a distal end;

(b) a base portion having means for connecting to an inner surface of said drum;

(c) a first side extending from said base portion towards a top portion of said lifter, wherein said first side forms a leading edge when said drum rotates in a first collecting direction;

(d) a second side extending from said base portion towards said top portion of said lifter, wherein said second side forms a leading edge when said drum rotates in a second collecting direction, wherein said second collecting direction is in the opposite rotational direction to said first collecting direction;

(e) a first collecting flow path to facilitate flow of said solid particulate material from the interior of said drum to a storage means in said drum when said drum rotates in said first collecting direction; and

(f) a first collecting aperture disposed in said first side, wherein said first collecting aperture defines the start of said first collecting flow path,

characterised in that said lifter comprises a second collecting flow path to facilitate flow of said solid particulate material from the interior of said drum to said storage means when said drum rotates in said second collecting direction, wherein said lifter comprises a second collecting aperture disposed in said second side, wherein said second collecting aperture defines the start of said second collecting flow path, and wherein said first collecting flow path and said second collecting flow path are different flow paths.

In this arrangement, said lifter comprises both said first collecting flow path and said second collecting flow path. In this way, said lifter can collect solid particulate material regardless of the direction of rotation of the drum. As such, said lifter may also be known as a“bidirectional lifter”. It will be appreciated that the features, preferences and embodiments described herein in respect of the first preferred embodiment of said first elongate protrusion are applicable also to the lifter of the second aspect of the invention.

According to a third aspect of the invention, there is provided an apparatus for use in the treatment of substrates with a solid particulate material, said apparatus comprising a housing having mounted therein a rotatably mounted drum having an inner surface and an end wall and access means for introducing said substrates into said drum, wherein said drum comprises:

(a) storage means for storage of said solid particulate material; and

(b) at least one lifter according to the invention described herein.

It will be appreciated that the features, preferences and embodiments described herein in respect of the apparatus and solid particulate material are applicable to the third aspect of the invention.

Apparatus having said second collecting flow path in a separate elongate protrusion

In a second preferred embodiment, said drum further comprises a second elongate protrusion located on said inner surface of said drum, wherein said second elongate protrusion extends in a direction away from said end wall, wherein said second elongate protrusion has an end proximal to the end wall and an end distal to the end wall, wherein said second elongate protrusion comprises said second collecting flow path and a second collecting aperture, wherein said second collecting aperture defines the start of said second collecting flow path. In this way, in addition to a first elongate protrusion as described above, the drum comprises a second elongate protrusion that is able to collect solid particulate material when the drum rotates in a second collecting direction.

The apparatus of the present invention may comprise a drum comprising said second elongate protrusion and a first elongate protrusion, wherein said first elongate protrusion comprises only a first collecting flow path. Alternatively, the apparatus of the present invention may comprise a drum comprising said second elongate protrusion and a first elongate protrusion, wherein said first elongate protrusion comprises a first collecting flow path and a second collecting flow path. Preferably, when said drum comprises a second elongate protrusion, said first elongate protrusion comprises a first collecting flow path and does not comprise a second collecting flow path.

Said second elongate protrusion located on the inner surface of the drum in the apparatus of the present invention is a type of“lifter”. Typically, said second elongate protrusion is disposed on the inner surface of the drum such that the elongate dimension of the protrusion is essentially perpendicular to the direction of rotation of the drum.

Said second collecting aperture may be disposed in a first side of said second elongate protrusion, wherein said first side of said second elongate protrusion is the leading side of said second elongate protrusion during rotation of the drum in said second collecting direction.

Said second elongate protrusion may comprise a plurality of said second collecting apertures disposed in said first side of said second elongate protrusion at a plurality of positions from the proximal end to the distal end thereof. Typically, there may be from about 2 to about 200, from about 3 to about 100, from about 4 to about 50, from about 5 to about 30, from about 6 to about 25, or from about 10 to about 20 second collecting apertures disposed on said first side of said second elongate protrusion. For domestic washing machines, preferably there are from about 5 to about 15 second collecting apertures disposed on said first side of said second elongate protrusion. For commercial substrate treatment machines, preferably there are from about 5 to about 100 second collecting apertures disposed on said first side of said second elongate protrusion.

Said second collecting aperture(s) may be any suitable size and shape to allow ingress of solid particulate material into said second collecting flow path. Typically, the shape of said second collecting aperture(s) is substantially rectangular, substantially circular, substantially square or substantially oval in shape. Preferably, the shape of said second collecting aperture(s) is substantially rectangular. Preferably, the second collecting aperture(s) is positioned in order that entry of said solid particulate material from the interior of said drum to the second collecting flow path is as free-flowing as possible.

Preferably, the second collecting aperture(s) is adjacent the inner surface of said drum. Typically, said second elongate protrusion comprises an arrangement of a plurality of second collecting apertures such that substantially the entire length of the first side of said second elongate protrusion from the proximal end to the distal end comprises second collecting apertures. Preferably, each aperture is separated from its neighbour or neighbours by a distance of about 10 mm or less, about 8 mm or less, about 5 mm or less, about 3 mm or less or about 1 mm or less. Preferably, the second collecting apertures comprise from about 50 to about 95%, preferably from about 60 to about 90% of the length of the first side of said second elongate protrusion. Having an arrangement with a plurality of closely spaced second collecting apertures allows for efficient collection (also known as“harvesting”) of solid particulate material from the interior of said drum. In particular, such an arrangement advantageously increases the opportunities for solid particulate material in the interior of the drum to strike a second collecting aperture when the drum is rotated in said second colleting direction and thus allows for ingress of said solid particulate material into said second collecting flow path.

Preferably the first side of said second elongate protrusion is adapted to bias solid particulate material towards said second collecting aperture(s).

For instance, said second collecting aperture(s) may have a funnel shape to increase the cross-sectional area at the entry to said second collecting flow path and thereby increase the probability of entry of solid particulate material into said second collecting flow path.

Additionally or alternatively, the region between adjacent second collecting apertures may be angled towards a collecting aperture, thereby encouraging solid particulate material to enter said second collecting flow path.

Optionally, said second elongate protrusion may comprise a collecting groove along at least part of the first side, wherein the collecting groove is configured to collect solid particulate material during rotation in said second collecting direction, whereupon the solid particulate material is biased towards the second collecting aperture(s) during further rotation in said second collecting direction. Such a collecting groove is preferably disposed in said second elongate protrusion along at least part of the edge of said second elongate protrusion where it meets the inner wall of the drum.

Preferably, said second elongate protrusion is configured to bias solid particulate material in said second collecting flow path towards the storage means during rotation of the drum in said second collecting direction. Preferably, said second elongate protrusion is further configured to prevent, more preferably to eliminate, solid particulate material present in said second collecting flow path from returning to the interior of said drum when the drum rotates in said first collecting direction. For instance, said second elongate protrusion may comprise one or more flap, paddle, gate or combination thereof that adopts an open position that permits solid particulate material in the second collecting flow path moving towards the storage means when the drum is rotating in said second collecting direction but adopts a closed position that prevents solid particulate material from re-entering the interior of said drum when the drum is rotating in said first collecting direction.

More preferably, said second elongate protrusion is configured to bias solid particulate material in said second collecting flow path towards the storage means during rotation of the drum in both said first collecting direction and in said second collecting direction. In this way, solid particulate material that has entered said second collecting flow path is able to continue to move towards the storage means even when the direction of rotation of the drum is reversed. This arrangement significantly reduces, and preferably completely eliminates, the amount of solid particulate material that re-enters the interior of the drum from said second collecting flow path when the direction of rotation of the drum is reversed. For instance, said second elongate protrusion may comprise an arrangement of deflectors that urges solid particulate material towards the storage means regardless of the direction of rotation of said drum.

Said second elongate protrusion may comprise one or more curved surfaces, or“ramps”, adjacent to said second collecting apertures that urges solid particulate material somewhat radially inwards and more towards the central axis of rotation of

the drum. Having a curved surface adjacent to a second collecting aperture can provide improved capture of the solid particulate material when the drum rotates at varying speeds. In addition, this arrangement helps prevent solid particulate material from exiting the second collecting apertures. Having a curved surface adjacent said second collecting apertures is particularly preferable where said second elongate protrusion comprises an arrangement of deflectors.

Preferably, said second elongate protrusion is spaced apart from said first elongate protrusion on said inner surface of said drum.

Preferably, said second elongate protrusion is rectilinear. Preferably, said first elongate protrusion and said second elongate protrusion are rectilinear.

The apparatus of the present invention preferably comprises a plurality of said first elongate protrusions and said second elongate protrusions. The drum preferably has from 2 to 10, preferably 2, 3, 4, 5 or 6 and preferably 2, 3 or 4, and preferably 3 or 4, of said first and second elongate protrusions. For domestic washing machines, 3 protrusions are most preferred. For commercial washing machines, 5 or 6 protrusions, and preferably 6 protrusions, are most preferred. Preferably, the drum comprises equal numbers of said first and said second elongate protrusions. Where a plurality of first and second elongate protrusions are located on the inner surface of the drum, all of the elongate protrusions typically have the same or substantially the same dimensions as each other. In alternative embodiments, a plurality of first and second elongate protrusions may have differing dimensions, i.e. one or more first and/or second elongate protrusions of a first size and/or shape, and one or more first and/or second elongate protrusions of a second size and/or shape, etc.

The features described in the following passages relate to all aspects and embodiments described above unless stated otherwise:

Said first elongate protrusions, said second elongate protrusions and the lifters of the present invention may be referred to generally herein as“elongate protrusions”.

A first collecting flow path is defined as a flow path of solid particulate material from a first collecting aperture to the storage means. A first collecting aperture defines the start of a first collecting flow path. Solid particulate material enters said first collecting flow path from the interior of the drum via a first collecting aperture. A first collecting flow path is in fluid communication with the storage means, and preferably there is no valve separating a first collecting flow path and the storage means.

Similarly, a second collecting flow path is defined as a flow path of solid particulate material from a second collecting aperture to the storage means. A second collecting aperture defines the start of a second collecting flow path. Solid particulate material enters said second collecting flow path from the interior of the drum via a second collecting aperture. A second collecting flow path is in fluid communication with the storage means, and preferably there is no valve separating a second collecting flow path and the storage means.

Preferably, whether solid particulate material is in said first collecting flow path or said second collecting flow path is determined by the collecting aperture through which the solid particulate material entered. For instance, solid particulate material that enters through a first collecting aperture travels to the storage means via said first collecting flow path, and solid particulate material that enters through a second collecting aperture travels to the storage means via said second collecting flow path.

Preferably, said first collecting flow path and/or said second collecting flow path comprises a series of deflectors which are configured to urge said solid particulate material towards said storage means during rotation of said drum. Preferably, said first collecting flow path and/or said second collecting flow path further comprises a plurality of series of deflectors

which are configured to urge said solid particulate material towards said storage means during rotation of said drum. Preferably, said first collecting flow path and/or said second collecting flow path comprises a first series of deflectors which are configured to urge said solid particulate material towards said storage means during rotation of said drum and a second series of deflectors which are configured to urge said solid particulate material towards said storage means during rotation of said drum. Preferably said first lengthwise portion and said second lengthwise portion of said first embodiment of said first elongate protrusion and/or said lifter comprise a series of deflectors or a plurality of series of deflectors as described herein.

Preferably, said series of deflectors, or each series of said plurality of series of deflectors, are inclined substantially parallel to each other. In this context, the term“substantially parallel” means that the respective deflectors make an angle with each other which is less than about 20°, preferably less than about 10°, preferably less than about 5°. Preferably, a series of deflectors in a plurality of series of deflectors are inclined substantially parallel to each other but are not substantially parallel to deflectors in other series of deflectors.

Preferably, said first collecting flow path and/or said second collecting flow path comprises a chain of open compartments which are configured to urge said solid particulate material towards said storage means during rotation of said drum. Preferably said first lengthwise portion and said second lengthwise portion of said first embodiment of said first elongate protrusion and/or said lifter comprise a chain of open compartments which are configured to urge said solid particulate material towards said storage means during rotation of said drum.

Preferably, said first collecting flow path and/or said second collecting flow path is or comprises an Archimedean screw arrangement. Preferably, said first lengthwise portion and said second lengthwise portion of said first embodiment of said first elongate protrusion and/or said lifter comprise an Archimedean screw arrangement. Typically, said Archimedean screw arrangement may comprise surfaces that are rectilinear or curvilinear or a combination thereof.

In a preferred embodiment, said first and second collecting flow path is or comprises an Archimedean screw arrangement which is located in said first elongate protrusion or said lifter of the invention. Alternatively, said first collecting flow path is or comprises an Archimedean screw arrangement which is located in said first elongate protrusion, and said second collecting flow path is or comprises an Archimedean screw arrangement which is located in said second elongate protrusion. As the drum is rotated in the collecting direction, the solid particulate material within said first and/or second collecting flow path is urged by the internal surfaces of the Archimedean screw along the collecting flow path and towards the storage means. Thus, as a result only of the rotation of the drum, the solid particulate material may be conveyed from the collecting aperture and/or collecting flow path to the storage means.

Preferably, the first elongate protrusion or said lifter comprises a pair of Archimedean screws, wherein the Archimedean screws are oppositely handed, that is, one of the pair of Archimedean screws has a clockwise path whereas the other pair of Archimedean screws has a counter-clockwise path.

Preferably, each screw pitch of said Archimedean screw arrangement is associated with a first or a second collecting aperture. Similarly, each open compartment in said chain of open compartments is associated with a first or a second collecting aperture.

Where said first elongate protrusion, second elongate protrusion and/or lifter as described above has a plurality of collecting apertures, preferably said first elongate protrusion, second elongate protrusion and/or lifter comprises a plurality of corresponding collecting flow paths. For instance, each of said first collecting flow paths starts at one of said plurality of first collecting apertures and then unites with other first collecting flow paths to form a single common first collecting flow path in said first elongate protrusion or said lifter, wherein said single common first collecting flow path is in fluid communication with said storage means. Preferably, said single common first collecting flow path comprises a chain of

open compartments or Archimedean screw arrangement as described herein. Preferably, each of said second collecting flow paths starts at one of said plurality of second collecting apertures and then unites with other second collecting flow paths to form a single common second collecting flow path in said first and/or second elongate protrusion or lifter, wherein said single common second collecting flow path is in fluid communication with said storage means. Preferably, said single common second collecting flow path comprises a chain of open compartments or Archimedean screw arrangement as described herein.

Preferably, one of said first or second collecting flow paths is or comprises a substantially clockwise path and the other of said first and second collecting flow paths is or comprises a substantially counter-clockwise path.

Preferably, movement of said solid particulate material between the interior of the drum and the storage means is actuated entirely by rotation of the drum. It will be appreciated that the term“actuated entirely by rotation of the drum” means that said movement of said particulate material is effected by the rotation of the drum and also affected by gravity. In particular, it will be appreciated that the term“actuated entirely by rotation of the drum” means that said movement of said solid particulate material between the storage means and the interior of the drum does not require a pump.

In the apparatus of the present invention, a first collecting flow path and a second collecting flow path are different flow paths. The first collecting flow path and the second collecting flow path may be partially but not completely coextensive. In other words, a portion (but not the entirety) of a first collecting flow path may occupy the same space as a portion of a second collecting flow path.

Preferably, said first and second collecting flow paths are constituted by the walls of a series of separate modular sections wherein each of said modular sections comprises a collecting aperture and a portion of said first and/or second collecting flow paths, wherein said series of separate modular sections, when joined together, form at least some of the boundary walls of said first and second collecting flow paths. Preferably, said modular sections form the internal walls of said first and/or second elongate protrusion, i.e. the walls of said first and/or second collecting flow paths, rather than the outer walls of the elongate protrusion which contact the substrates in the interior of the drum. A modular arrangement has the advantage of easier and more economic manufacturing, for instance by injection moulding. Preferably the modular sections in this embodiment are joined together linearly, preferably by means of a tie-bar which extends from the first to the last modular section. The assembly comprising the tie-bar and joined modular sections are suitably covered by the outer skin of the elongate protrusion (typically a stainless steel outer skin), which extends from the proximate end to the distal end thereof. Thus, the tie bar is suitably located within said first and/or second elongate protrusion, or lifter, preferably within the lobe which is most remote from the inner surface of the drum, or juxtaposed with the trailing edge of the elongate protrusion or lifter during rotation of the drum in a collecting direction.

Said Archimedean screw may be motorised but preferably the inner surfaces of the Archimedean screw are static, relative to the inner wall of the drum, i.e. the inner surfaces of the Archimedean screw preferably do not rotate independently of the rotation of the drum.

The inner surfaces of the Archimedean screw suitably have a conventional circular and/or smooth arrangement. Alternatively or additionally, the Archimedean screw is rectilinear, having stepped surfaces along at least a part of its length. Similarly, while the cross-section of an Archimedean screw is suitably circular, other cross-sections are envisaged, and particularly multi-lobal cross-sections, such as tri-lobal or quadri-lobal. A trilobal cross-section is of particular utility because the elongate protrusions within which the Archimedean screw is disposed are typically triangular in cross-section; hence a trilobal cross-section for the Archimedean screw makes the best possible use of the space available inside the elongate protrusion. Rectilinear arrangements are of particular utility because the elongate protrusion, or lifter, may be manufactured in multiple pieces and assembled together to form the flow paths discussed hereinabove in said first elongate protrusion, second elongate protrusion or lifter. Suitable manufacturing processes include injection moulding.

In another preferred embodiment, referred to herein as the paternoster configuration, said chain of open compartments are formed by a first series of inclined vanes substantially parallel to each other and a second series of inclined vanes substantially parallel to each other. In this context, the term“substantially parallel” means that the respective vanes make an angle with each other which is less than about 20°, preferably less than about 10°, preferably less than about 5°.

Preferably, said first and second series are disposed along at least part of the length of the interior of said first and/or second elongate protrusion or lifter. Said first series of vanes may be disposed in a facing arrangement to said second series of vanes, wherein said first series of vanes are not parallel to said second series of vanes, and wherein the compartments and vanes are configured to bias solid particulate material present inside said first and/or second collecting flow path towards said storage means during rotation of the drum in a first and/or second collecting direction.

In a further preferred embodiment, said chain of open compartments is formed by opposing and offset saw-tooth surfaces configured to bias solid particulate material present inside said first and/or said second collecting flow path towards said storage means during rotation of the drum.

Optionally, said first elongate protrusion, said second elongate protrusion and/or said lifter may comprise one or more perforations which have dimensions smaller than the smallest dimension of the solid particulate material so as to permit passage of fluids through said perforations but to prevent passage of said solid particulate material through said perforations.

The first and/or second elongate protrusion, or lifter, may comprise an aperture in which a tie bar can be located. The aperture may be located proximal to the top portion of the elongate protrusion. The first and second collecting flow paths may be located radially outward of the tie bar aperture, i.e. distally from the centre of the drum relative to the tie bar. This arrangement may provide increased stiffness for the drum and may allow for an elongate protrusion of reduced width. Having an elongate protrusion with narrow width, and preferably also rounded shaping, provides advantageous movement, especially tumbling, of the substrate, the solid particulate material and liquid medium, where present. If the elongate protrusion is too wide it reduces the available volume within the drum and, therefore, reduces the available batch volume or washload for the treatment cycle. An elongate protrusion having a substantially triangular cross-section with a curved top portion is particularly preferred.

The specific nature of the first collecting flow path which solid particulate material follows on passing through a first collecting aperture may depend on the particular location of the first collecting aperture through which the solid particle material has passed. For example, solid particulate material that passes through a first collecting aperture that is positioned along the elongate protrusion at a position distal to the end wall may follow a first collecting flow path that is longer and/or more tortuous than the first collecting flow path followed by solid particulate material that passes through a first collecting aperture closer to the end wall of the drum. Similarly, where said first elongate protrusion and/or said second elongate protrusion comprises a plurality of said second collecting apertures disposed in said second side, the specific nature of the second collecting flow path which solid particulate material follows on passing through a second collecting aperture may depend on the particular location of the second collecting aperture through which the solid particle material has passed. For example, solid particulate material that passes through a second collecting aperture that is positioned along the elongate protrusion at a position distal to the end wall may follow a second collecting flow path that is longer and/or more tortuous than the second collecting flow path followed by solid particulate material that passes through a second collecting aperture closer to the end wall of the drum.

The first collecting flow path may comprise a plurality of types of first collecting flow path. Preferably, the first collecting flow path comprises a first type of first collecting flow path and a second type of first collecting flow path. Alternatively or in addition, the second collecting flow path may comprise a plurality of types of second collecting flow path. Preferably, the second collecting flow path comprises a first type of second collecting flow path and a second type of second collecting flow path.

Said first elongate protrusion may comprise a first portion having a first set of first collecting apertures, wherein each first collecting aperture in said first set of first collecting apertures defines the start of a first type of first collecting flow path, and a second portion having a second set of first collecting apertures, wherein each first collecting aperture in said second set of first collecting apertures defines the start of a second type of first collecting flow path. Typically, each of said first type of first collecting flow paths starts at one of said first collecting apertures in said first set of first collecting apertures and then unites with other first type of first collecting flow paths along at least part of its flow path to form a partially common first type of first collecting flow path in said first elongate protrusion or said lifter, wherein said partially common first type of first collecting flow path is in fluid communication with said storage means. Each of said second type of first collecting flow paths may start at one of said first collecting apertures in said second set of first collecting apertures and then unite with other second type of first collecting flow paths to form a single common second type of first collecting flow path in said first elongate protrusion or said lifter, wherein said single common second type of first collecting flow path is in fluid communication with said storage means. Typically, said first elongate protrusion may comprise an internal structure that varies the nature of the first collecting flow path followed by solid particulate material depending on the location of the first collecting aperture through which the solid particulate material has passed. For example, said first set of first collecting apertures may define the start of a first type of first collecting flow path that is or comprises a chain of open compartments or an Archimedean screw arrangement as described herein, and said second set of first collecting apertures may define the start of a second type of first collecting flow path that is or comprises a compound arcuate or helicoidal path. Preferably, said first set of first collecting apertures is positioned in the elongate protrusion distal to the end wall of the drum whereas the second set of first collecting apertures is positioned nearer to the end wall of the drum. More preferably, the second set of first collecting apertures is positioned adjacent the end wall of the drum. In this way, the second type of first collecting flow path may be shorter and/or less tortuous than the first type of first collecting flow path. An advantage of this arrangement may be faster and more efficient collection of solid particulate material, particularly during an initial stage of collection of solid particulate material from the drum. This arrangement may be particularly advantageous where the rotational axis of the drum is inclined relative to the horizontal direction such that solid particulate material is biased towards the end wall of the drum under the influence of gravity.

Alternatively or in addition, said first elongate protrusion and/or said second elongate protrusion may comprise a first portion having a first set of second collecting apertures, wherein each second collecting aperture in said first set of second collecting apertures defines the start of a first type of second collecting flow path, and a second portion having a second set of second collecting apertures, wherein each second collecting aperture in said second set of second collecting apertures defines the start of a second type of second collecting flow path. Typically, each of said first type of second collecting flow paths starts at one of said second collecting apertures in said first set of second collecting apertures and then unites with other first type of second collecting flow paths along at least part of its flow path to form a partially common first type of second collecting flow path in said elongate protrusion, wherein said partially common first type of second collecting flow path is in fluid communication with said storage means. Each of said second type of second collecting flow paths may start at one of said second collecting apertures in said second set of second collecting apertures and then unite with other second type of second collecting flow paths to form a single common second type of second collecting flow path in said elongate protrusion, wherein said single common second type of second collecting flow path is in fluid communication with said storage means. Typically, said first elongate protrusion and/or said second elongate protrusion may comprise an internal structure that varies the nature of the second collecting flow path followed by solid particulate material depending on the location of the second collecting aperture through which the solid particulate material has passed. For example, said first set of second collecting apertures may define the start of a first type of second collecting flow path that is or comprises a chain of open compartments or an Archimedean screw arrangement as described herein, and said second set of second collecting apertures may define the start of a second type of second collecting flow path that is or comprises a compound arcuate or helicoidal path. Preferably, said first set of second collecting apertures is

positioned in the elongate protrusion distal to the end wall of the drum whereas the second set of second collecting apertures is positioned nearer to the end wall of the drum. More preferably, the second set of second collecting apertures is positioned adjacent the end wall of the drum. In this way, the second type of second collecting flow path may be shorter and/or less tortuous than the first type of second collecting flow path. An advantage of this arrangement may be faster and more efficient collection of solid particulate material, particularly during an initial stage of collection of solid particulate material from the drum. This arrangement may be particularly advantageous where the rotational axis of the drum is inclined relative to the horizontal direction such that solid particulate material is biased towards the end wall of the drum under the influence of gravity.

The term“set” as used herein in relation to the first collecting apertures, can refer to a single first collecting aperture or a plurality of first collecting apertures. The term“set” as used herein in relation to the second collecting apertures, can refer to a single second collecting aperture or a plurality of second collecting apertures.

Preferably, said second set of first collecting apertures and/or said second set of second collecting apertures define a second type of first collecting flow path and a second type of second collecting flow path, respectively, that comprise a compound arcuate or helicoidal path. Independently of each other, the second type of first collecting flow path and the second type of second collecting flow path may direct solid particulate material in a curved path, generally moving the solid particulate material radially inwards, then axially and optionally radially outwards towards the end wall of the drum. This arrangement is particularly preferred when said second set of first collecting apertures and said second set of second collecting apertures is positioned nearer to the end wall of the drum than said first set of first collecting apertures and said first set of second collecting apertures, respectively. In this way, the second type of first collecting flow path and the second type of second collecting flow path may be significantly shorter than said first type of first collecting flow path and/or said first type of second collecting flow path.

CLAIMS

1. An apparatus for use in the treatment of substrates with a solid particulate material, said apparatus comprising a housing having mounted therein a rotatably mounted drum having an inner surface and an end wall and access means for introducing said substrates into said drum, wherein

(a) said drum comprises storage means for storage of said solid particulate material; and

(b) said drum comprises a first collecting flow path to facilitate flow of said solid particulate material from the interior of said drum to said storage means when said drum rotates in a first collecting direction,

characterised in that said drum comprises a second collecting flow path to facilitate flow of said solid particulate material from the interior of said drum to said storage means when said drum rotates in a second collecting direction, wherein said second collecting direction is in the opposite rotational direction to said first collecting direction, and wherein said first collecting flow path and said second collecting flow path are different flow paths.

2. The apparatus according to claim 1 , wherein said drum has a first elongate protrusion located on said inner surface of said drum wherein said first elongate protrusion extends in a direction away from said end wall, wherein said first elongate protrusion has an end proximal to the end wall and an end distal to the end wall, wherein said first elongate protrusion comprises said first collecting flow path and further comprises a first collecting aperture, wherein said first collecting aperture defines the start of said first collecting flow path.

3. The apparatus according to claim 2, wherein said first collecting aperture is disposed in a first side of said first elongate protrusion, wherein said first side of said first elongate protrusion is the leading side of said first elongate protrusion during rotation of the drum in said first collecting direction.

4. The apparatus according to claim 3, wherein said first elongate protrusion comprises a plurality of said first collecting apertures disposed in said first side of said first elongate protrusion at a plurality of positions from the proximal end to the distal end thereof.

5. The apparatus according to any of claims 2 to 4, wherein said first elongate protrusion is configured to bias solid particulate material present inside said first collecting flow path towards the storage means during rotation of the drum in said first collecting direction and in said second collecting direction.

6. The apparatus according to any of claims 2 to 5, wherein said first elongate protrusion further comprises said second collecting flow path and a second collecting aperture, wherein said second collecting aperture defines the start of said second collecting flow path.

7. The apparatus according to claim 6, wherein said second collecting aperture is disposed in a second side of said first elongate protrusion, wherein said second side of said first elongate protrusion is the leading side of said first elongate protrusion during rotation of the drum in said second collecting direction.

8. The apparatus according to claim 7, wherein said first elongate protrusion comprises a plurality of said second collecting apertures disposed in said second side of said first elongate protrusion at a plurality of positions from the proximal end to the distal end thereof.

9. The apparatus according to any of claims 6 to 8, wherein said first elongate protrusion is configured to bias solid particulate material present inside said second collecting flow path towards the storage means during rotation of the drum in said first collecting direction and in said second collecting direction.

10. The apparatus according to any of claims 2 to 9, wherein said first elongate protrusion is rectilinear.

11. The apparatus according to any of claims 6 to 10, wherein said first collecting flow path and said second collecting flow path are symmetrically arranged along the length of said first elongate protrusion.

12. The apparatus according to any of claims 6 to 11 , wherein said first elongate protrusion comprises a barrier projecting from a base portion of said first elongate protrusion adjacent the inner surface of said drum, wherein said barrier extends at least partially towards a top portion of said first elongate protrusion, wherein said barrier at least partially separates said first collecting flow path and said second collecting flow path.

13. The apparatus according to any of claims 6 to 12, wherein said first side and/or said second side of said first elongate protrusion is inclined so that the width of said first elongate protrusion is narrower at a top portion of said first elongate protrusion than at a base portion of the elongate protrusion adjacent the inner surface of said drum.

14. The apparatus according to any of claims 2 to 13, wherein said drum comprises a plurality of said first elongate protrusions.

15. The apparatus according to claim 14, wherein said drum comprises two, three, four, five or six of said first elongate protrusions.

16. The apparatus according to any of claims 2 to 15, wherein said drum further comprises a second elongate protrusion located on said inner surface of said drum, wherein said second elongate protrusion extends in a direction away from said end wall, wherein said second elongate protrusion has an end proximal to the end wall and an end distal to the end wall, wherein said second elongate protrusion comprises said second collecting flow path and a second collecting aperture, wherein said second collecting aperture defines the start of said second collecting flow path.

17. The apparatus according to claim 16, wherein said second collecting aperture is disposed in a first side of said second elongate protrusion, wherein said first side of said second elongate protrusion is the leading side of said second elongate protrusion during rotation of the drum in said second collecting direction

18. The apparatus according to claim 17, wherein said second elongate protrusion comprises a plurality of said second collecting apertures disposed in said first side of said second elongate protrusion at a plurality of positions from the proximal end to the distal end thereof.

19. The apparatus according to any of claims 16 to 18, wherein said second elongate protrusion is configured to bias solid particulate material present inside said second collecting flow path towards the storage means during rotation of the drum in said first collecting direction and in said second collecting direction.

20. The apparatus according to any of claims 16 to 19, wherein said second elongate protrusion is spaced apart from said first elongate protrusion on said inner surface of said drum.

21. The apparatus according to any of claims 16 to 20, wherein said first elongate protrusion and/or said second elongate protrusion is rectilinear.

22. The apparatus according to any of claims 16 to 21 , wherein said drum comprises a plurality of said first and/or said second elongate protrusions.

23. The apparatus according to claim 22, wherein the total number of said first and second elongate protrusions comprised in the drum is two, three, four, five or six.

24. The apparatus according to claim 23, wherein the total number of said first and second elongate protrusions comprised in the drum is two, four or six and wherein the number of said first elongate protrusions is equal to the number of said second elongate protrusions.

25. The apparatus according to any preceding claim, wherein said first collecting flow path and/or said second collecting flow path comprises a series of deflectors which are configured to urge said solid particulate material towards said storage means during rotation of said drum.

26. The apparatus according to claim 25, wherein said deflectors are inclined substantially parallel to each other.

27. The apparatus according to any preceding claim, wherein said first collecting flow path and/or said second collecting flow path comprises a chain of open compartments which are configured to urge said solid particulate material towards said storage means during rotation of said drum.

28. The apparatus according to any of claims 1 to 24, wherein said first collecting flow path and/or said second collecting flow path is or comprises an Archimedean screw arrangement.

29. The apparatus according to claim 28, wherein said Archimedean screw arrangement comprises surfaces that are rectilinear or curvilinear or a combination thereof.

30. The apparatus according to any of claims 25 to 29, wherein one of said first or second collecting flow paths comprises a substantially clockwise path and the other of said first and second collecting flow paths comprises a substantially counter-clockwise path.

31. The apparatus according to any preceding claim wherein movement of said solid particulate material between the interior of the drum and the storage means is actuated entirely by rotation of the drum.

32. The apparatus according to any preceding claim, wherein said storage means is or comprises at least one cavity located in the end wall of the drum.

33. The apparatus according to any preceding claim wherein the storage means comprises multiple compartments, for instance, 2, 3, 4, 5 or 6 compartments, particularly wherein said multiple compartments are arranged so as to retain balance of the drum during rotation.

34. The apparatus according to claim 33 further comprising a delivery duct in fluid communication between said first collecting flow path and/or said second collecting flow path and a compartment of said storage means, wherein said delivery duct is configured to transfer said solid particulate material from said first collecting flow path and/or said second collecting flow path to said compartment, preferably such that entry of said solid particulate material into said compartment occurs when said compartment is oriented so as to reduce the amount of solid particulate material already in said compartment that is adjacent a point of entry into the compartment compared to the amount of solid particulate material adjacent the point of entry when said compartment is in other orientations during rotation of said drum, preferably entry of said solid particulate material into said compartment occurs when at least a portion of said compartment is above the horizontal plane bisecting the axis of drum rotation.

35. The apparatus according to claim 34, wherein said delivery duct comprises a least one baffle to regulate the flow of solid particulate material from the delivery duct into said compartment.

36. The apparatus according to claim 34 or claim 35, wherein said delivery duct is located around a portion of the circumference of the end wall of the drum.

37. The apparatus according to any of claims 34 to 36, wherein said delivery duct comprises a first entry aperture and a first exit aperture, wherein the first entry aperture is in fluid communication with said first collecting flow path and/or said second collecting flow path and is configured such that solid particulate material is able to enter the delivery duct through said first entry aperture and pass through the delivery duct as the drum rotates in said first collecting direction before passing through the first exit aperture and into a compartment of the storage means.

38. The apparatus according to claim 37, wherein said delivery duct further comprises a second entry aperture and a second exit aperture, wherein the second entry aperture is in fluid communication with said first collecting flow path and/or said second collecting flow path and is configured such that solid particulate material is able to enter the delivery duct through the second entry aperture and pass through the delivery duct as the drum rotates in said second collecting direction before passing through the second exit aperture and into a compartment of the storage means, preferably said second entry aperture and said first entry aperture are the same aperture.

39. The apparatus according to claim 38, wherein the delivery duct further comprises:

(a) a central portion comprising said first and second entry apertures;

(b) a first arm extending from said central portion in a first direction around the circumference of said end wall to a first end of said delivery duct; and

(c) a second arm extending from said central portion in a second direction around the circumference of said end wall to a second end of said delivery duct, wherein said first exit aperture is adjacent said first end and said second exit aperture is adjacent said second end.

40. The apparatus according to claim 39, wherein said delivery duct comprises a first arrangement of one or more baffles configured to regulate the flow of solid particulate material that nears the first exit aperture of the delivery duct when said first exit aperture is below the horizontal plane bisecting the axis of drum rotation as the drum rotates in said first collecting direction, and wherein said first arrangement of one or more baffles is further configured to allow solid particulate material to pass through the first exit aperture and enter the compartment of the storage means when said compartment is oriented so as to reduce the amount of solid particulate material already in said compartment that is adjacent the point of entry into the compartment compared to the amount of solid particulate material adjacent the point of entry when said compartment is in other orientations during rotation of said drum, preferably, said first arrangement of one or more baffles is configured to allow solid particulate material to pass through the first exit aperture and enter the compartment when the first exit aperture moves above the horizontal plane bisecting the axis of drum rotation as the drum rotates in said first collecting direction.

41. The apparatus according to claim 39 or claim 40, wherein said delivery duct comprises a second arrangement of one or more baffles configured to regulate the flow of solid particulate material that nears the second exit aperture of the delivery duct when said second exit aperture is below the horizontal plane bisecting the axis of drum rotation as the drum rotates in said second collecting direction, and wherein said second arrangement of one or more baffles is further configured to allow solid particulate material to pass through said second exit aperture and enter the compartment of the storage means when said compartment is oriented so as to reduce the amount of solid particulate material already in said compartment that is adjacent the point of entry into the compartment compared to the amount of solid particulate material adjacent the point of entry when said compartment is in other

orientations during rotation of said drum, preferably, said second arrangement of one or more baffles is configured to allow solid particulate material to pass through the second exit aperture and enter the compartment when said second exit aperture moves above the horizontal plane bisecting the axis of drum rotation as the drum rotates in said second collecting direction.

42. The apparatus according to any preceding claim, wherein the storage means comprises multiple compartments located in the end wall of the drum, wherein each of the compartments is defined by a cavity bound by a first wall and a second wall which each extend outwards from the rotational axis of the drum towards and preferably to the inner wall of the drum, preferably wherein each compartment is associated with a single first collecting flow path and a single second collecting flow path.

43. The apparatus according to claim 42, wherein each compartment is in fluid communication with its adjacent compartment or compartments such that solid particulate material, as well as any liquid medium, is able to pass from one compartment directly into an adjacent compartment during rotation of the drum.

44. The apparatus according to claim 43, wherein fluid communication between adjacent compartments is effected by a communicating aperture in the wall between adjacent compartments, preferably wherein a communicating aperture exhibits a smallest dimension which is at least 4 times greater than the longest dimension of the solid particulate material, and preferably wherein the largest dimension of the communicating aperture is no greater than 50% of the longest dimension of a wall between adjacent compartments, and preferably wherein said communicating aperture is located in a wall between adjacent compartments at a point that is closer to the midpoint of said wall between adjacent compartments than to either the rotational axis of the drum or the inner wall of the drum.

45. The apparatus according to any preceding claim, wherein the storage means further comprises one or more perforations which have dimensions smaller than the dimensions of the solid particulate material so as to permit passage of fluids through said perforations into and out of the storage means, particularly from or into the interior of said drum respectively, but to prevent egress of said solid particulate material through said perforations.

46. The apparatus according to any preceding claim wherein the dimensions of said first and second collecting flow paths are such that they have no internal dimension which is less than 2 times, more preferably less than 3 times, the longest dimension of the solid particulate material.

47. An apparatus according to any preceding claim wherein the storage means and/or said first and/or second collecting flow paths can be assembled inside the drum, and/or are able to be retrofitted to an existing drum, and/or are removable and replaceable.

48. The apparatus according to any preceding claim, wherein the inner surface of said drum comprises perforations which have dimensions smaller than the dimensions of the solid particulate material so as to permit passage of fluids into and out of said drum but to prevent egress of said solid particulate material.

49. The apparatus according to claim 48, wherein said housing is a tub which surrounds said drum, preferably wherein said tub and said drum are substantially concentric, preferably wherein the walls of said tub are unperforated but having disposed therein one or more inlets and/or one or more outlets suitable for passage of a liquid medium and/or one or more treatment agents into and out of the tub.

50. The apparatus according to any preceding claim further comprising a seal between the access means and said tub.

51. The apparatus according to any preceding claim, wherein said drum has an opening at the opposite end of the drum to the end wall through which said substrates are introduced into said drum.

52. The apparatus according to any preceding claim, wherein said drum comprises a dispensing aperture and a dispensing flow path for facilitating flow of said solid particulate material from said storage means to the interior of said drum.

53. The apparatus according to claim 52, wherein said dispensing aperture is comprised in said end wall of said drum.

54. The apparatus according to any preceding claim, wherein the apparatus does not comprise a further storage means which is not attached to or integral with the drum, and/or wherein the apparatus does not comprise a pump for circulating said solid particulate material between the storage means and the interior of the drum.

55. The apparatus according to any preceding claim wherein the apparatus does not comprise a pump for circulating said solid particulate material.

56. The apparatus according to any preceding claim wherein said treatment of substrates with solid particulate material is in the presence of a liquid medium and/or one of more treatment formulation(s).

57. The apparatus according to any preceding claim which comprises said solid particulate material.

58. The apparatus according to any preceding claim wherein the particles of the solid particulate material have (i) an average mass of from about 1 mg to about 1000 mg; and/or (ii) an average volume in the range of from about 5 to about 500 mm3; and/or (iii) an average surface area of from 10 mm2 to 500 mm2 per particle; and/or (iv) an average particle size of from 1 mm to 50 mm, preferably from 2 to 20mm, preferably from 5mm to 10mm; and/or (v) and average density of at least about 1 g/cm3 or at least about 1.4 g/cm3.

59. The apparatus according to any preceding claim wherein the particles of the solid particulate comprise a polymer, preferably wherein the polymer is or comprises a polyalkylene, a polyamide, a polyester or a polyurethane, preferably a polyalkylene, polyester or polyamide, preferably a polyamide selected from nylon 6 or nylon 6,6 or a polyalkylene selected from polypropylene, and preferably a polyamide or a polyamide selected from nylon 6 or nylon 6,6.

60. The apparatus according to any preceding claim wherein the particles of the solid particulate material are spheroidal or ellipsoidal or a mixture thereof.

61. The apparatus according to any preceding claim wherein the rotatable drum is cylindrical.

62. A lifter for use in a rotatably mounted drum of an apparatus for use in the treatment of substrates with a solid particulate material, the lifter comprising:

(a) an elongate body having a proximal end and a distal end;

(b) a base portion having means for connecting to an inner surface of said drum;

(c) a first side extending from said base portion towards a top portion of said lifter, wherein said first side forms a leading edge when said drum rotates in a first collecting direction;

(d) a second side extending from said base portion towards said top portion of said lifter, wherein said second side forms a leading edge when said drum rotates in a second collecting direction, wherein said second collecting direction is in the opposite rotational direction to said first collecting direction;

(e) a first collecting flow path to facilitate flow of said solid particulate material from the interior of said drum to a storage means in said drum when said drum rotates in said first collecting direction; and

(f) a first collecting aperture disposed in said first side, wherein said first collecting aperture defines the start of said first collecting flow path,

characterised in that said lifter comprises a second collecting flow path to facilitate flow of said solid particulate material from the interior of said drum to said storage means when said drum rotates in said second collecting direction, wherein said lifter comprises a second collecting aperture disposed in said second side, wherein said second collecting aperture defines the start of said second collecting flow path, and wherein said first collecting flow path and said second collecting flow path are different flow paths.

63. The lifter according to claim 62, comprising a plurality of said first collecting apertures disposed in said first side of said lifter at a plurality of positions from the proximal end to the distal end thereof.

64. The lifter according to claim 62 or claim 63, wherein said lifter is configured to bias solid particulate material present inside said first collecting flow path towards said proximal end during rotation of the drum in said first collecting direction and in said second collecting direction.

65. The lifter according to any of claims 62 to 64, comprising a plurality of said second collecting apertures disposed in said second side of said lifter at a plurality of positions from the proximal end to the distal end thereof.

66. The lifter according to any of claims 62 to 65, wherein said lifter is configured to bias solid particulate material present inside said second collecting flow path towards said proximal end during rotation of the drum in said first collecting direction and in said second collecting direction.

67. The lifter according to any of claims 62 to 66, wherein said lifter is rectilinear.

68. The lifter according to any of claims 62 to 67, wherein said first collecting flow path and said second collecting flow path are symmetrically arranged along the length of said elongate body of said length.

69. The lifter according to any of claims 62 to 68, wherein said lifter comprises a barrier projecting from said base portion, wherein said barrier extends at least partially towards said top portion, wherein said barrier at least partially separates said first collecting flow path and said second collecting flow path.

70. The lifter according to any of claims 62 to 69, wherein said first side and/or said second side of said lifter is inclined so that the width of said lifter is narrower at said top portion than at said base portion.

71. The lifter according to any of claims 62 to 70, wherein said first collecting flow path and/or said second collecting flow path comprises a series of deflectors which are configured to urge said solid particulate material towards said proximal end during rotation of said drum.

72. The lifter according to claim 71 , wherein said deflectors are inclined substantially parallel to each other.

73. The lifters according to any of claims 62 to 72, wherein said first collecting flow path and/or said second collecting flow path comprises a chain of open compartments which are configured to urge said solid particulate material towards said proximal end during rotation of said drum.

74. The lifter according to any of claims 62 to 73 wherein said first collecting flow path and/or said second collecting flow path is or comprises an Archimedean screw arrangement.

75. The lifter according to claim 74 wherein said Archimedean screw arrangement comprises surfaces that are rectilinear or curvilinear or a combination thereof.

76. The lifter according to any of claims 62 to 75, wherein one of said first or second collecting flow paths comprises a substantially clockwise path and the other of said first and second collecting flow paths comprises a substantially counter-clockwise path.

77. An apparatus for use in the treatment of substrates with a solid particulate material, said apparatus comprising a housing having mounted therein a rotatably mounted drum having an inner surface and an end wall and access means for introducing said substrates into said drum, wherein said drum comprises:

(a) storage means for storage of said solid particulate material; and

(b) at least one lifter according to any of claims 62 to 76.

78. A method of treating a substrate, the method comprising agitating the substrate in an apparatus according to any of claims 1 to 61 or 77 with solid particulate material.

79. The method according to claim 78 wherein the solid particulate material is re-used in further treatment procedures according to the method.

80. The method according to claim 78 or 79 wherein the method is a method for treating multiple batches, wherein a batch comprises at least one substrate, the method comprising agitating a first batch with solid particulate material, wherein said method further comprises the steps of:

(a) collecting said solid particulate material in the storage means;

(b) agitating a second batch comprising at least one substrate with solid particulate material collected from step (a); and

(c) optionally repeating steps (a) and (b) for subsequent batch(es) comprising at least one substrate.

81. The method according to any of claims 78 to 80 wherein the method comprises agitating the substrate with solid particulate material and a liquid medium, preferably wherein the liquid medium is aqueous.

82. The method according to any of claims 78 to 81 wherein the method comprises agitating the substrate with said solid particulate material and a treatment formulation.

83. The method according to any of claims 78 to 82 wherein the substrate is or comprises a textile.

84. The method according to claim 83 wherein the treating of said substrate is cleaning, coloration, bleaching, abrading or ageing, or other textile or garment finishing process.

85. The method according to claim 84 for cleaning a substrate wherein the substrate is a soiled substrate.

86. The method according to any of claims 78 to 82 wherein the substrate is or comprises an animal skin substrate.

87. The method according to claim 86 wherein the treating of an animal skin substrate is a tannery process.

88. A kit for converting an apparatus which is not suitable for use in the treatment of substrates using a solid particulate material into an apparatus according to any of claims 1 to 61 which is suitable for use in the treatment of substrates using a solid particulate material, wherein the apparatus comprises a housing having mounted therein a rotatably mounted drum having an inner surface and an end wall and which further comprises access means for introducing said substrates into said drum, and wherein said kit comprises:

(a) solid particulate material;

(b) storage means for storage of said solid particulate material; and

(c) at least one first elongate protrusion having a first collecting flow path and a second collecting flow path, or at least one first elongate protrusion having a first collecting flow path in combination with at least one second elongate protrusion having a second collecting flow path as defined in claims 2 to 30, or at least one lifter as defined in claims 34 to 41 ,

wherein said first collecting flow path facilitates flow of said solid particulate material from the interior of said drum to said storage means when said drum rotates in a first collecting direction, wherein said second collecting flow path facilitates flow of said solid particulate material from the interior of said drum to said storage means when said drum rotates in a second collecting direction, wherein said second collecting direction is in the opposite rotational direction to said first collecting direction, and wherein said first collecting flow path and said second collecting flow path are different flow paths,

wherein said kit is adapted to allow affixing of said storage means and said first elongate protrusion(s) and, where present, said second elongate protrusion(s) to one or more interior surface(s) of the drum.

89. A method of constructing an apparatus according to any of claims 1 to 61 which is suitable for use in the treatment of substrates using a solid particulate material, the method comprising retrofitting a starting apparatus which is not suitable for use in the treatment of substrates using a solid particulate material and which comprises a housing having mounted therein a rotatably mounted drum having an inner surface and an end wall and which further comprises access means for introducing said substrates into said drum, wherein said retrofitting comprises the steps of:

(i) providing solid particulate material, providing one or more storage means for storage of solid particulate material, and providing at least one elongate protrusion(s);

(ii) affixing said storage means to one or more interior surface(s) of the drum; and

(iii) affixing to an interior surface of the drum at least one first elongate protrusion having a first collecting flow path and a second collecting flow path, or at least one first elongate protrusion having a first collecting flow path and at least one second elongate protrusion having a second collecting flow path or, in particular, at least one lifter as defined in claims 34 to 41 ,

wherein said first collecting flow path facilitates flow of said solid particulate material from the interior of said drum to said storage means when said drum rotates in a first collecting direction, wherein said second collecting flow path facilitates flow of said solid particulate material from the interior of said drum to said storage means when said drum rotates in a second collecting direction, wherein said second collecting direction is in the opposite rotational direction to said first collecting direction, and wherein said first collecting flow path and said second collecting flow path are different flow paths.