WO2019073270A1

WO2019073270A1 - Lifter, rotatable drum, apparatus and method

Info

Publication number: WO2019073270A1
Application number: PCT/GB2018/052962
Authority: WO
Inventors: Steven Marlon ROBERTS; Manpreet Singh Sokhi; Joseph MATTLEY
Original assignee: Xeros Limited
Priority date: 2017-10-13
Filing date: 2018-10-15
Publication date: 2019-04-18
Also published as: TW201932668A; GB201716854D0

Abstract

Lifter (1000, 100, 200, 300, 400, 500, 600, 700, 800, 900) for a rotatable drum of an apparatus for use in the treatment of substrates with a solid particulate material, the lifter (1000, 100, 200, 300, 400, 500, 600, 700, 800, 900) comprises an elongate body (1002, 102, 202, 302, 402, 602, 702) having a base portion (1004, 104, 204, 304, 404, 704) having means for connecting to an inner cylindrical surface (116, 316) of the drum, and one or more agitation surfaces (1006A, 106A, 206A, 306A, 406A, 606A, 706A, 806A,1006B, 106B, 206B, 306B, 406B, 606B, 706B, 806B) extending away from the base portion (1004, 104, 204, 304, 404, 704) on a corresponding one or more sides of the elongate body (1002, 102, 202, 302, 402, 602, 702), said lifter (1000, 100, 200, 300, 400, 500, 600, 700, 800, 900) has one or more passageways passing through the elongate body (1002, 102, 202, 302, 402, 602, 702) from the one or more sides, each passageway defining at least part of a flow path between an inlet in at least one of the sides of the elongate body (1002, 102, 202, 302, 402, 602, 702) and an outlet in the base portion (1004, 104, 204, 304, 404, 704), to allow solid particulate material to pass out of one or more openings (658, 910) in the cylindrical surface (116, 316) of the drum via the one or more passageways, the lifter (1000, 100, 200, 300, 400, 500, 600, 700, 800, 900) has a plurality of structures (452) defining the inlets in the at least one side of the elongate body (1002, 102, 202, 302, 402, 602, 702), wherein at least one surface of each structure (452) extends from the inlet into the body (102) of the lifter (1000, 100, 200, 300, 400, 500, 600, 700, 800, 900) for a distance of at least 5mm.

Description

LIFTER, ROTATABLE DRUM, APPARATUS AND METHOD

The present disclosure relates to a lifter, such as may be used in a rotatable drum of a treatment apparatus that can employ a multiplicity of solid particulate material in the treatment of substrates, particularly a substrate which is or comprises a textile. The present disclosure further relates to a drum comprising a lifter, and to an apparatus comprising the drum, as well as the operation of an apparatus for the treatment of substrates using solid particulate material. The invention particularly relates to a lifter, a drum, an apparatus and method for cleaning of soiled substrates.

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 particulate material 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 and WO2012/167545. 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 publications, for instance WO2014/167358, WO2014/167359, WO2016/05118, WO/2016/055789 and WO2016/055788, teach the advantages provided by solid particulate material in other fields such as leather treatment and tanning. A challenge with existing apparatuses is how to handle and/or store the solid particulate material. Solutions exist for storing the particulate material in a rotatable drum of an apparatus, or outside the drum in a dedicated repository, or in a sump within that apparatus.

A challenge with arrangements wherein particulate material is stored and/or processed outside the drum is how to remove particulate material from the drum. Drums in such apparatus are typically perforated, and one solution is to use particulate material of smaller size than the diameter of a perforation, such that the particulate material passes out of the drum through the perforations. This approach is disclosed in, for example, WO2011/098815. The diameter of one existing kind of particulate material is 4.5mm, which will pass through the apertures in the drums of some existing 25kg and 16kg washing machines, examples of which are 5.3 to 5.4mm in diameter. However, in certain circumstances it is desirable to use particulate material which is larger than the diameter of existing or conventional drum perforations. For instance, the diameter of another known kind of particulate material is 6.5mm. This size of particulate material is less prone to being retained by substrates within the drum, but will not pass through the drum apertures mentioned above. In these situations, clearly a different solution is needed for handling the particulate material. In conventional apparatus, as well as in apparatus adapted for the treatment of substrates using solid particulate material, it is known to dispose one or more so-called "lifters" onto the inner surface of the drum. These lifters encourage circulation and agitation of the contents (i.e. the substrate(s), treatment agents or treatment formulations and solid particulate material) within the drum during rotation of the drum. These lifters preferably take the form of a multiplicity of spaced apart elongate protrusion(s) affixed to the inner surface of the drum. Typically, the elongate protrusions are 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. Thus, the elongate protrusion preferably extends in a direction away from said end wall, and preferably extends from said end wall. The elongate protrusion therefore has an end proximal to the end wall and an end distal to the end wall. As will now be described, lifters have previously been configured to handle the solid particulate material.

GB1704736.6 describes an apparatus for use in the treatment of substrates with a solid particulate material comprising a rotatable drum and storage means within the drum for storing solid particulate material for use in said treatment. In this case, the solid particulate material does not pass through the cylindrical wall of the drum. The drum and storage means are configured with a dispensing flow path and a collecting flow path which allow particulate material to enter the drum from the storage means and be collected from the drum into the storage means through channels which pass through a plurality of elongate protrusions similar in form to lifters, and which open on a surface of the protrusions. The storage means in this case is mounted about the end wall of the drum, and the channels are configured to convey the particulate material along the length of the elongate protrusions between the storage means at the end wall of the drum, and the openings in the surfaces. Another arrangement of a rotatable drum handling particulate material is disclosed in WO2014/147391 , which discloses storage of the particulate material within the lifters. Again, in this case the solid particulate material does not pass through the cylindrical wall of the drum. A storage compartment is provided within the lifters. Access to the storage compartment is by a convoluted flow path which opens at an edge of the lifter. By rotation of the drum in one direction, the particulate material enters and navigates the convoluted flow path from the drum to arrive in the storage compartment. By rotation of the drum in the opposite direction, the process is reversed and particulate material re-enters the drum.

WO2014/147389 likewise describes an apparatus for use in the treatment of substrates with a solid particulate material comprising a rotatable drum. In this case, however, storage of the particulate material takes place not in the drum itself, but in a repository mounted outside the rotatable drum. The apparatus comprises lifters with an opening to allow particulate material to pass into the body of the lifter where in one embodiment it is held within a rotatable door mounted within the lifter. The purpose of the door is to hold the particulate material until such time as it can be released from the lifter into the repository. This happens by bringing a protrusion fixed to the door into contact with a wall on the repository. The door is thus caused to rotate dropping the particulate material held within through an opening in the lifter and the door through the wall of the drum and into the repository.

The present inventors newly found that when certain lifters were employed, there could be some degree of undesirable damage to the substrate. Thus, the present inventors sought to provide lifters having improved fabric care whilst still allowing the solid particulate material to easily pass therethrough. The present inventors prepared several lifters in an attempt to solve this problem. An example of one of those lifters, which is not according to the invention and which is prone to damaging garments, in particular to tearing buttons from shirts, is shown in figures 4 and 5. This lifter 900 is made from thin sheet metal of thickness 3mm and has openings 910, 912, 914 arranged in three rows within the sheet metal. The inventors found that substrates, particularly shirts and other garments with buttons, zips or other protruding features, would be prone to damage by these lifters, as those feature became caught and trapped by the openings, thereby stretching and even tearing the garment.

Following on from these findings, the present inventors desired to provide even better apparatus for treatment methods which involve the use of solid particulate material. In particular, the present inventors desired to address the problems mentioned above concerning handling of solid particulate material whilst providing apparatuses which reduce damage to substrates. The present inventors furthermore desired 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 address a problem that the present inventors discovered can afflict these kinds of apparatuses, namely unwanted retention of particles in the substrates after treatment has finished.

Accordingly, in a first aspect, the present invention provides a lifter for use in a rotatable drum of an apparatus for use in the treatment of substrates with a solid particulate material, the lifter comprising:

an elongate body having a base portion having means for connecting to an inner cylindrical surface of the drum, and one or more agitation surfaces extending away from the base portion on a corresponding one or more sides of the elongate body;

one or more passageways passing through the elongate body from the one or more sides, each passageway defining at least part of a flow path between an inlet in at least one of the sides of the elongate body and an outlet in the base portion, to allow solid particulate material to pass out of one or more openings in the cylindrical surface of the drum via the one or more passageways; and

a plurality of structures defining the inlets in the at least one side of the elongate body, wherein at least one surface of each structure extends from the inlet into the body of the lifter for a distance of at least 5mm.

The apparatus may be a washing machine (washer), tumble dryer (dryer) or a combination washer-dryer, either for use in domestic or commercial settings. Alternatively the apparatus may be any other apparatus with a rotatable drum which may be used in treating substrates. The agitation surfaces are the parts of the lifter which come into contact with substrates in the drum.

As mentioned, the lifter has one or more passageways, preferably at least 5, preferably at least 10, preferably at least 15, preferably at least 20.

The inlets in at least one of the sides of the elongate body may be located underneath the one or more agitation surfaces, between the one or more agitation surfaces and the base portion. Preferably, however, the inlets in at least one of the sides of the elongate body are provided by apertures in the one or more agitation surfaces themselves. The agitation surfaces may be planar surfaces. In that case, the plurality of structures may be channels extending from said apertures, each channel being at least partially enclosed by one or more one channel walls. Preferably, the channels are tubular. Each channel is at least partially enclosed by one or more channel walls which extend from the aperture of the respective channel into the body of the lifter for a distance of at least 5mm. Preferably the one or more channel walls extend further, for example for a distance of at least 6mm, preferably at least 7mm, more preferably at least 8mm, more preferably at least 10mm, more preferably at least 15mm, more preferably at least 20mm, more preferably at least 25mm, more preferably at least 30mm.

Preferably the inlets in at least one of the sides of the elongate body are provided by apertures in the one or more agitation surfaces. However, in alternative configurations the inlets may be located beneath, to the side of or even above the agitation surfaces.

In one configuration, the one or more channel walls includes at least a channel base wall, which is the channel wall that is closest to the base portion of the elongate body. Preferably the configuration also includes one or more opposing channel side walls perpendicular to the channel base wall.

At least part, preferably, all of the edge of each aperture in the one or more agitation surfaces is bevelled, chamfered or rounded. Likewise, where an inlet is defined by edges or features other than apertures in an agitation surface, at least part, preferably all of those edges or features is bevelled, chamfered or rounded.

Preferably, the elongate body extends along an axis and each aperture has a substantially rectangular shape, preferably a rounded rectangular shape, preferably a stadium shape, with long edges parallel to the axis and short edges perpendicular to the axis. In some cases, the long edges of the apertures of the first row of inlets may be aligned. Of course, other shapes of aperture are possible, such as circular, triangular, square, pentagonal, hexagonal or other suitable geometry. Preferably, the base is rectangular in plan. However, this is not essential, and the base (and lifter) may be curved, curvilinear or any other suitable shape.

Preferably, the lifter has one or more support surfaces extending along the length of the lifter, as part of its base portion, for resting on the cylindrical surface of the drum. In an alternative embodiment, the lifter has a plurality of fins which include shoulders for resting on the cylindrical surface of the drum. In both cases, the lifter is supported on the cylindrical surface of the drum at the edges of an opening therein, with a portion of the lifter extending at least partially into the opening for support. The lifter may be secured to the drum either internally or externally with screws and/or rivets and/or a snap fit feature on the base portion of the lifter. A combination of these securing means may be used. The one or more (preferably two) agitation surfaces that stand up from the base portion and extend into the drum, in use, may either meet at an apex such that the body approximates a triangular prism, or be joined together by a top surface such that the body approximates a trapezoidal prism. Of course, other shapes and configurations are possible, including first and second agitation surfaces having an arcuate shape such that the body approximates a half cylinder.

The size and shape of the inlet for the particulate matter is significant (though not essential) for the success of the design. Preferably, each inlet has a substantially rectangular shape, which may be a rounded rectangular shape (i.e. a rectangle with rounded corners) or a stadium shape (the ends of which are half-circles). In all cases, however, the inlets possess long edges which run parallel to the axis defined by the length of the elongate member. In use in a rotatable drum, the long edge will typically run parallel to the axis of rotation of the drum and perpendicular to the direction of rotation. The inlets may be arranged in rows. Preferably at least one row, more preferably two or three rows are provided. In each row, the long edges of the inlets are aligned, and for the purposes of reference in the description the second row is the one which is further away from the base portion than the first row, and the third row is further away from the base portion than the first and second rows.

The inlets in the rows (however many there are) may be aligned along columns such that the short edges of the apertures in the first row are aligned with corresponding short edges of the inlets in the second row. Alternatively, the inlets in adjacent rows, preferably all rows, may be offset from each other such that the short edges of the inlets in the first row are not aligned with corresponding short edges of the inlets in the second row. In a particular example preferably the inlets in adjacent rows are staggered, and preferably the staggering is such that the centre of each inlets in one row is equidistant between the centres of two adjacent inlets in an adjacent row. Preferably the first and second rows of inlets are spaced apart from each other, in a direction perpendicular to the long edges of the apertures and parallel with the short edges of the apertures, by a distance of at least 5mm, preferably 6mm, preferably 7mm, preferably 8mm, preferably 10mm, preferably 15mm, preferably 20mm, preferably 25mm, preferably 30mm, preferably 40mm.

In some embodiments, the agitation surface is at least partially provided by a plate, in which case the plurality of channels are provided by one or more inserts coupled to the one or more plates. Alternatively, the elongate body may comprise an integral moulding which provides the one or more agitation surfaces and defines the plurality of channels.

The integral moulding, where used, may be provided in first and second symmetrical portions, each comprising at least one agitation surface and defining one set of a plurality of channels extending from apertures in said at least one agitation surface. The first and second symmetrical portions are connected together by at least one fixing means.

Preferably the integral moulding provides opposing first and second agitation surfaces and defines two sets of a plurality of tubular channels, each extending from apertures in the respective opposing agitation surfaces.

In some cases, the plurality of channels may be orthogonal to the agitation surface. Alternatively, the plurality of channels may be orthogonal to a plane of symmetry of the elongate body and/or parallel to the base portion.

In other embodiments, the plurality of structures may comprise a plurality of spaced-apart fins, lozenges or cylinders, each inlet occupying a space between two adjacent structures. The agitation surface may terminate in an angled wall extending into the body of the lifter. This is a useful arrangement because the plurality of structures can occupy a region between the wall and the base portion.

The plurality of structures may be a plurality of fins or lozenges, wherein each fin or lozenge extends the length of the region between the angled wall and the base portion. Alternatively, the plurality of structures may be a plurality of cylinders, wherein the cylinders are arranged in a plurality of spaced-apart rows distributed along the length of the region between the angled wall and the base portion. The angled wall may be at an angle of 90 degrees or more to the agitation surface, preferably at an angle of 100 degrees or more, preferably at an angle of 110 degrees or more at an angle of 120 degrees or more. Preferably, the channel walls of each channel, where provided, at least comprise a channel top wall that is curved toward the base portion. This will guide at least some particulate material passing through the channels such that it is directed toward the base portion and therefore out of the opening in the cylindrical surface of the drum.

Advantageously, the lifter preferably comprises one or more deflectors positioned within the body to at least partially intersect the flow path or otherwise intercept the particulate material such that at least some particulate material passing through the channels comes into contact with the one or more deflectors and is thereby directed toward the base portion and therefore out of the opening in the cylindrical surface of the drum. The deflector may take the form of a plate passing through the body, which is otherwise separate from the channels. In that case, the one or more channels are oriented toward the plate such that the particulate material passing through the channels comes into contact with the plate. It will be appreciated that a gap must exist between the channel and the plate to enable the particulate matter to drop, after contacting the plate, through the gap toward the base portion and therefore out of the opening in the cylindrical surface of the drum. To that end, there may be a channel base wall, the end of which is spaced apart from the plate. Alternatively, the deflector may be provided by a curved or angled wall. In one example, each channel (if provided) may have a channel top wall (which is the channel wall which is furthest away from the base portion of the elongate body) comprising a lip extending from the channel top wall toward the base. This will serve to direct particles toward the base portion and therefore out of the opening in the cylindrical surface of the drum. Again, it will be appreciated that a gap may be provided underneath the lip to enable the particulate matter to fall toward the base and therefore out of the opening in the cylindrical surface of the drum, after contacting the lip. To that end, there may be a channel base wall, the length of which is shorter than the channel top wall. It is preferable that the lifter is symmetrical about a plane extending along the length of the lifter and passing through both the base portion and the top edge. In use, the drum is preferably rotated in both directions, and it is envisaged that the particulate matter may pass out of the drum through the lifter irrespective of which way the drum is rotating. Having the same configuration on both sides of the lifter is useful to ensure efficient removal of particulate matter when the drum is rotating in either direction. Preferably there is no flow path in the lifter for the sold particulate material to enter into the drum via the lifter during use.

The invention also provides a rotatable drum for use in an apparatus for use in the treatment of substrates with a solid particulate material, the rotatable drum having an end wall and an inner cylindrical wall comprising perforations and at least one opening, and at least one lifter according to any preceding claim, wherein the elongate body of the lifter extends from the end wall, and wherein the lifter is positioned on the inner cylindrical wall over an opening to allow particulate material to pass from the interior of the drum through the one or more passageways in the at least one lifter and out of the at least one opening, wherein each of the perforations has a largest dimension that is smaller than the smallest linear dimension of the inlets in the lifter.

As mentioned, the drum according to the invention has at least one lifter, but may have two, three, four, five or six lifters, if preferred.

Preferably, where a plurality of lifters are provided, the lifters are parallel to each other, and are preferably equidistantly spaced on the inner cylindrical wall of the rotatable drum. In certain embodiments, each of the perforations has a largest dimension smaller than the dimensions of the solid particulate material so as to permit passage of fluids through said perforations, particularly from the interior of said drum, but to prevent egress of said solid particulate material through said perforations. Because the inlets are larger than the dimensions of the solid particulate material, these can pass through. However, the present inventors have also newly found that where each of the perforations has a largest dimension that is larger than the dimensions of the solid particulate material, the invention provides an additional advantage by way of a reduction of the unwanted retention of solid particulate material. In this case, removal of the solid particulate material can be via both the perforations and/or the inlets, and here the inventors have newly observed an improvement in removal of the solid particulate material compared the use of the same drum with the use of lifters not according to the invention.

Preferably, the lifters can be assembled inside the drum, and/or are able to be retrofitted to an existing drum, and/or are removable and replaceable.

Preferably there is no storage for solid particulate material within the drum, as there is provided with certain alternative bead handling solutions described above. The invention also provides an apparatus for use in the treatment of substrates with a solid particulate material. The apparatus comprises a housing having mounted therein a rotatably mounted drum as described above. The housing also has access means for introducing said substrates into said drum. There is preferably a seal between the access means and the drum such that, in use, solid particulate material is not able to leave the drum through the access means; i.e. via any gap between the access means and the drum. Preferably the access means is a door that is attached via hinges to the housing. Preferably the housing comprises a tub which surrounds the drum. In this configuration, the tub and drum are preferably concentric. Preferably the walls of the tub are unperforated but have 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, for example into a sump within the housing that collects the solid particulate material, liquid medium and treatment agents.

The apparatus of the present invention is preferably configured for the treatment of substrates with solid particulate material in the presence of a liquid medium and/or one of more treatment formulations or agents.

Preferably, the apparatus includes a recirculation means, such as a pump, for returning solid particulate material from a sump, or other chamber in which it collects, to the drum. Suitable configurations to enable recirculation have been described in one or more of the publications mentioned elsewhere herein.

The solid particulate material preferably comprises a multiplicity of particles. Typically, the number of particles is no less than 1000, more typically no less than 10,000, even more typically no less than 100,000. A large number of particles is particularly advantageous in preventing creasing and/or for improving the uniformity of treating or cleaning of the substrate, particularly wherein the substrate is a textile.

Preferably, the particles have an average mass of from about 1 mg to about 1000 mg, or from about 1 mg to about 700 mg, or from about 1 mg to about 500 mg, or from about 1 mg to about 300 mg, preferably at least about 10 mg, per particle. Preferably, the particles preferably have an average mass of from about 1 mg to about 150 mg, or from about 1 mg to about 70 mg, or from about 1 mg to about 50 mg, or from about 1 mg to about 35 mg, or from about 10 mg to about 30 mg, or from about 12mg to about 25 mg. In an alternative embodiment, the particles preferably have an average mass of from about 10 mg to about 800 mg, or from about 20mg to about 700mg, or from about 50 mg to about 700 mg, or from about 70 mg to about 600 mg from about 20mg to about 600mg. In one preferred embodiment, the particles have an average mass of about 25 to about 150 mg, preferably from about 40 to about 80 mg. In a further preferred embodiment, the particles have an average mass of from about 150 to about 500 mg, preferably from about 150 to about 300 mg.

The average volume of the particles is preferably in the range of from about 5 to about 500 mm³, from about 5 to about 275 mm³, from about 8 to about 140 mm³, or from about 10 to about 120 mm³, or at least 40 mm³, for instance from about 40 to about 500 mm³, or from about 40 to about 275 mm³, per particle.

The average surface area of the particles is preferably from 10 mm² to 500 mm² per particle, preferably from 10mm² to 400mm², more preferably from 40 to 200mm² and especially from 50 to 190mm².

The particles preferably have an average particle size of at least 1 mm, preferably at least 2mm, preferably at least 3mm, preferably at least 4 mm, and preferably at least 5mm. The particles preferably have an average particle size no more than 100mm, preferably no more than 70mm, preferably no more than 50mm, preferably no more than 40mm, preferably no more than 30mm, preferably no more than 20mm, preferably no more than 10mm, and optionally no more than 7mm. Preferably, the particles have an average particle size of from 1 to 20mm, more preferably from 1 to 10mm. Particles which offer an especially prolonged effectiveness over a number of treatment cycles are those with an average particle size of at least 5mm, preferably from 5 to 10mm. The size is preferably the largest linear dimension (length). For a sphere this equates to the diameter. For non-spheres this corresponds to the longest linear dimension. The size is preferably determined using Vernier callipers. The average particle size is preferably a number average. The determination of the average particle size is preferably performed by measuring the particle size of at least 10, more preferably at least 100 particles and especially at least 1000 particles. The above mentioned particle sizes provide especially good performance (particularly cleaning performance) whilst also permitting the particles to be readily separable from the substrate at the end of the treatment method.

The particles preferably have an average particle density of greater than 1 g/cm³, more preferably greater than 1.1 g/cm³, more preferably greater than 1.2g/cm³, even more preferably at least 1.25g/cm³ and especially preferably greater than 1.3g/cm³. The particles preferably have an average particle density of no more than 3g/cm³ and especially no more than 2.5g/cm³. Preferably, the particles have an average density of from 1.2 to 3g/cm³. These densities are advantageous for further improving the degree of mechanical action which assists in the treatment process and which can assist in permitting better separation of the particles from the substrate after the treatment.

The particles of the solid particulate material may be polymeric and/or non-polymeric particles. Suitable non-polymeric particles may be selected from metal, alloy, ceramic and glass particles. Preferably, however, the particles of the solid particulate material are polymeric particles.

Preferably the particles comprise a thermoplastic polymer. A thermoplastic polymer, as used herein, preferably means a material which becomes soft when heated and hard when cooled. This is to be distinguished from thermosets (e.g. rubbers) which will not soften on heating. A more preferred thermoplastic is one which can be used in hot melt compounding and extrusion.

Preferably the solid particulate material has a solubility in water of no more than 1wt%, more preferably no more than 0.1 wt% in water and most preferably the polymer is insoluble in water. Preferably the water is at pH 7 and a temperature of 20°C whilst the solubility test is being performed. The solubility test is preferably performed over a period of 24 hours. The solid particulate material is preferably not degradable. By the words "not degradable" it is preferably meant that the polymer is stable in water without showing any appreciable tendency to dissolve or hydrolyse. For example, the polymer shows no appreciable tendency to dissolve or hydrolyse over a period of 24hrs in water at pH 7 and at a temperature of 20°C. Preferably a polymer shows no appreciable tendency to dissolve or hydrolyse if no more than about 1 wt%, preferably no more than about 0.1 wt% and preferably none of the polymer dissolves or hydrolyses, preferably under the conditions defined above.

The polymer may be crystalline or amorphous or a mixture thereof.

The polymer can be linear, branched or partly cross-linked (preferably wherein the polymer is still thermoplastic in nature), more preferably the polymer is linear.

The polymer preferably is or comprises a polyalkylene, a polyamide, a polyester or a polyurethane and copolymers and/or blends thereof, preferably from polyalkylenes, polyamides and polyesters, preferably from polyamides and polyalkylenes , and preferably from polyamides.

A preferred polyalkylene is polypropylene.

A preferred polyamide is or comprises an aliphatic or aromatic polyamide, more preferably an aliphatic polyamide. Preferred polyamides are those comprising aliphatic chains, especially C4-C16, C4-C12 and C4-C10 aliphatic chains. Preferred polyamides are or comprise Nylons. Preferred Nylons include Nylon 4,6, Nylon 4, 10, Nylon 5, Nylon 5,10, Nylon 6, Nylon 6,6, Nylon 6/6,6, Nylon 6,6/6, 10, Nylon 6, 10, Nylon 6, 12, Nylon 7, Nylon 9, Nylon 10, Nylon 10, 10, Nylon 11 , Nylon 12, Nylon 12, 12 and copolymers or blends thereof. Of these, Nylon 6, Nylon 6,6 and Nylon 6,10, and particularly Nylon 6 and Nylon 6,6, and copolymers or blends thereof are preferred. It will be appreciated that these Nylon grades of polyamides are not degradable, wherein the word degradable is preferably as defined above.

Suitable polyesters may be aliphatic or aromatic, and preferably derived from an aromatic dicarboxylic acid and a C1-C6, preferably C2-C4 aliphatic diol. Preferably, the aromatic dicarboxylic acid is selected from terephthalic acid, isophthalic acid, phthalic acid, 1 ,4-, 2,5- , 2,6- and 2,7-naphthalenedicarboxylic acid, and is preferably terephthalic acid or 2,6- naphthalenedicarboxylic acid, and is most preferably terephthalic acid. The aliphatic diol is preferably ethylene glycol or 1 ,4-butanediol. Preferred polyesters are selected from polyethylene terephthalate and polybutylene terephthalate. Useful polyesters can have a molecular weight corresponding to an intrinsic viscosity measurement in the range of from about 0.3 to about 1.5 dl/g, as measured by a solution technique such as ASTM D-4603.

Preferably, polymeric particles comprise a filler, preferably an inorganic filler, suitably an inorganic mineral filler in particulate form, such as BaSCU. The filler is preferably present in the particle in an amount of at least 5wt%, more preferably at least 10wt%, even more preferably at least 20wt%, yet more preferably at least 30wt% and especially at least 40wt% relative to the total weight of the particle. The filler is typically present in the particle in an amount of no more than 90wt%, more preferably no more than 85wt%, even more preferably no more than 80wt%, yet more preferably no more than 75wt%, especially no more than 70wt%, more especially no more than 65wt% and most especially no more than 60wt% relative to the total weight of the particle. The weight percentage of filler is preferably established by washing. Preferred washing methods include ASTM D2584, D5630, IS03451 and ISO50640, and preferably the test method is conducted according to ASTM D5630. For any standards referred to in the present invention, unless specified otherwise, the definitive version of the standard is the most recent version which precedes the priority filing date of this patent application. Preferably, the matrix of said polymer optionally comprising filler(s) and/or other additives extends throughout the whole volume of the particles. The particles can be spheroidal or substantially spherical, ellipsoidal, cylindrical or cuboid. Particles having shapes which are intermediate between these shapes are also possible. The best results for treatment performance (particularly cleaning performance) and separation performance (separating the substrate from the particles after the treating steps) in combination are typically observed with ellipsoidal and spheroidal particles. Spheroidal particles tend to separate best but may not provide optimum treatment or cleaning performance. Conversely, cylindrical or cuboid particles separate poorly but treat or clean effectively. Spheroidal and ellipsoidal particles are particularly useful where improved fabric care is important because they are less abrasive. The term "spheroidal", as used herein, encompasses spherical and substantially spherical particles. Preferably, the particles are not perfectly spherical. Preferably, the particles have an average aspect ratio of greater than 1 , more preferably greater than 1.05, even more preferably greater than 1.07 and especially greater than 1.1. Preferably, the particles have an average aspect ratio of less than 5, preferably less than 3, preferably less than 2, preferably less than 1.7 and preferably less than 1.5. The average is preferably a number average. The average is preferably performed on at least 10, more preferably at least 100 particles and especially at least 1000 particles. The aspect ratio for each particle is preferably given by the ratio of the longest linear dimension divided by the shortest linear dimension. This is preferably measured using Vernier Callipers. Where a good balance between treating performance (particularly cleaning performance) and substrate care is required, it is preferred that the average aspect ratio is within the abovementioned values. When the particles have a very low aspect ratio (e.g. highly spherical particles), the particles may not provide sufficient mechanical action for good treating or cleaning characteristics. When the particles have an aspect ratio which is too high, the removal of the particles from the substrate may become more difficult and/or the abrasion on the substrate may become too high, which may lead to unwanted damage to the substrate, particularly wherein the substrate is a textile.

Accordingly, in a second aspect of the invention there is provided a method of treating a substrate using solid particulate material in an apparatus for use in the treatment of substrates, the apparatus having a rotatable drum having one or more lifters, the method comprising the steps of: rotating the rotatable drum to treat the substrate by causing contact between the substrate and both the solid particulate material and the one or more lifters; and

removing the particulate material from the drum by passing the particulate material through one or more passageways passing through the lifter, each defining at least part of a flow path between a respective inlet in a side of the lifter and one or more openings in the cylindrical wall of the drum with which the lifter is aligned;

wherein the step of causing contact between the substrate and the one or more lifters comprises contacting at least a portion of the substrate with at least a portion of one of a plurality of structures defining the inlets in a side of the lifter, wherein at least one surface of each structure extends from the inlet into the body of the lifter for a distance of at least 5mm.

The steps of rotating the rotatable drum and removing the particulate material from the drum may take place simultaneously or consecutively in either order, or non-consecutively. Also provided is a method of treating a substrate, the method comprising agitating the substrate in an apparatus as described above with solid particulate material.

Preferably, the solid particulate material is re-used in further treatment procedures according to the method.

Preferably the method is a method for treating multiple batches. In this case, a batch comprises at least one substrate and the method comprising agitating a first batch with the solid particulate material. The method for treating multiple batches comprises the steps of: (a) collecting at least a portion of the solid particulate material in a storage means; and (b) agitating a second batch comprising at least one substrate with the at least of a portion of the solid particulate material collected from step (a).

The treatment procedure of an individual batch typically comprises the steps of agitating the batch with said solid particulate material in a treatment apparatus for a treatment cycle. A treatment cycle typically comprises one or more discrete treatment step(s), optionally one or more rinsing step(s), optionally one or more step(s) of separating the particles from the treated batch, optionally one or more extraction step(s) of removing liquid medium from the treated batch, optionally one or more drying step(s), and optionally the step of removing the treated batch from the apparatus.

In the method of the present invention, steps (a) and (b) may be repeated at least 1 time, preferably at least 2 times, preferably at least 3 times, preferably at least 5 times, preferably at least 10 times, preferably at least 20 times, preferably at least 50 times, preferably at least 100 times, preferably at least 200 times, preferably at least 300 times, preferably at least 400 at least or preferably at least 500 times.

The substrate may be or comprise a textile and/or an animal skin substrate. In a preferred embodiment, the substrate is or comprises a textile. The textile may be in the form of an item of clothing such as a coat, jacket, trousers, shirt, skirt, dress, jumper, underwear, hat, scarf, overalls, shorts, swim wear, socks and suits. The textile may also be in the form of a bag, belt, curtains, rug, blanket, sheet or a furniture covering. The textile can also be in the form of a panel, sheet or roll of material which is later used to prepare the finished item or items. The textile can be or comprise a synthetic fibre, a natural fibre or a combination thereof. The textile can comprise a natural fibre which has undergone one or more chemical modifications. Examples of natural fibres include hair (e.g. wool), silk and cotton. Examples of synthetic textile fibres include Nylon (e.g. Nylon 6,6), acrylic, polyester and blends thereof. As used herein, the term "animal skin substrate" includes skins, hides, pelts, leather and fleeces. Typically, the animal skin substrate is a hide or a pelt. The hide or pelt may be a processed or unprocessed animal skin substrate. The treating of a substrate which is or comprises a textile according to the present invention may be a cleaning process or any other treatment process such as coloration (preferably dyeing), ageing or abrading (for instance stone-washing), desizing, bleaching or other finishing process. Stonewashing is a known method for providing textiles having "worn in" or "stonewashed" characteristics such as a faded appearance, a softer feel and a greater degree of flexibility. Stonewashing is frequently practiced with denim. Preferably the treating of a substrate which is or comprises a textile is a cleaning process. The cleaning process may be a domestic or industrial cleaning process.

As used herein, the term "treating" in relation to treating an animal skin substrate is preferably a tannery process, including colouring and tanning and associated tannery processes, preferably selected from curing, beamhouse treatments, pre-tanning, tanning, re-tanning, fat liquoring, enzyme treatment, tawing, crusting, dyeing and dye fixing, preferably wherein said beamhouse treatments are selected from soaking, liming, deliming, reliming, unhairing, fleshing, bating, degreasing, scudding, pickling and depickling. Preferably, said treating of an animal skin substrate is a process used in the production of leather. Preferably, said treating acts to transfer a tanning agent (including a colourant or other agent used in a tannery process) onto or into the animal skin substrate. The treatment formulation referred to herein may comprise one or more treatment agent(s) which are suitable to effect the desired treating of the substrate. Thus, a method according to the present invention which is a cleaning process suitably comprises agitating the substrate with said solid particulate material, a liquid medium and one or more treatment formulation(s) or agents wherein said treatment formulation or treatment agent is preferably a detergent composition comprising one or more of the following components: surfactants, dye transfer inhibitors, builders, enzymes, metal chelating agents, biocides, solvents, stabilizers, acids, bases and buffers.

Similarly, the treatment formulation or agent of a coloration process is preferably a composition comprising one or more dyes, pigments, optical brighteners and mixtures thereof.

The treatment formulation or agent of a stone-washing process may comprise an appropriate stone-washing agent, as known in the art, for instance an enzymatic treatment agent such as a cellulase or an oxidant such as hypochlorite. The treatment formulation or agent of a tannery process suitably comprises one or more agent(s) selected from tanning agents, re-tanning agents and tannery process agents. The treatment formulation or agent may comprise one or more colourant(s). The tanning or re- tanning agent is preferably selected from synthetic tanning agents, vegetable tanning or vegetable re-tanning agents and mineral tanning agents such as chromium (III) salts or salts and complexes containing iron, zirconium, aluminium and titanium. Suitable synthetic tanning agents include amino resins, polyacrylates, fluoro and/or silicone polymers and formaldehyde condensation polymers based on phenol, urea, melamine, naphthalene, sulphone, cresol, bisphenol A, naphthol and/or biphenyl ether. Vegetable tanning agents comprise tannins which are typically polyphenols. Vegetable tanning agents can be obtained from plant leaves, roots and especially tree barks. Examples of vegetable tanning agents include the extracts of the tree barks from chestnut, oak, redoul, tanoak, hemlock, quebracho, mangrove, wattle acacia; and myrobalan. Suitable mineral tanning agents comprise chromium compounds, especially chromium salts and complexes, typically in a chromium (III) oxidation state, such as chromium (III) sulphate. Other tanning agents include aldehydes (glyoxal, glutaraldehyde and formaldehyde), phosphonium salts, metal compounds other than chromium (e.g. iron, titanium, zirconium and aluminium compounds). Preferably, the tanning agents are substantially free from chromium-containing compounds. One or more substrates can be simultaneously treated by the method of the invention. The exact number of substrates will depend on the size of the substrates and the capacity of the apparatus utilized.

The total weight of dry substrates treated at the same time (i.e. in a single batch orwashload) may be up to 50,000 kg. For textile substrates, the total weight is typically from 1 to 500 kg, more typically 1 to 300 kg, more typically 1 to 200 kg, more typically from 1 to 100 kg, even more typically from 2 to 50 kg and especially from 2 to 30 kg. For animal substrates, the total weight is normally at least about 50 kg, and can be up to about 50,000 kg, typically from about 500 to about 30,000 kg, from about 1000 kg to about 25,000 kg, from about 2000 to about 20,000 kg, or from about 2500 to about 10,000 kg.

Preferably the liquid medium is an aqueous medium, i.e. the liquid medium is or comprises water. In order of increasing preference, the liquid medium comprises at least 50wt%, at least 60wt%, at least 70wt%, at least 80wt%, at least 90wt%, at least 95wt% and at least 98wt% of water. The liquid medium may optionally comprise one or more organic liquids including for example alcohols, glycols, glycol ethers, amides and esters. Preferably, the sum total of all organic liquids present in the liquid medium is no more than 10wt%, more preferably no more than 5wt%, even more preferably no more than 2wt%, especially no more than 1 % and most especially the liquid medium is substantially free from organic liquids.

The liquid medium preferably has a pH of from 3 to 13. The pH or the treatment liquor can differ at different times, points or stages in the treatment method according to the invention. It can be desirable to treat (particularly to clean) a substrate under alkaline pH conditions, although while higher pH offers improved performance (particularly cleaning performance) it can be less kind to some substrates. Thus, it can be desirable that the liquid medium has a pH of from 7 to 13, more preferably from 7 to 12, even more preferably from 8 to 12 and especially from 9 to 12. In a further preferred embodiment, the pH is from 4 to 12, preferably 5 to 10, especially 6 to 9, and most especially 7 to 9, particularly in order to improve fabric care. It may also be desirable that the treating of a substrate, or one or more specific stage(s) of a treatment process, is conducted under acid pH conditions. For instance, certain steps in the treatment of animal skin substrates are advantageously conducted at a pH which is typically less than 6.5, even more typically less than 6 and most typically less than 5.5, and typically no less than 1 , more typically no less than 2 and most typically no less than 3. Certain fabric or garment finishing treatment methods, for instance stone-washing, may also utilise one or more acidic stage(s). An acid and/or base may be added in order to obtain the abovementioned pH values. Preferably, the abovementioned pH is maintained for at least a part of the duration, and in some preferred embodiments for all of the duration, of the agitation. In order to prevent the pH of the liquid medium from drifting during the treatment, a buffer may be used.

Preferably, the weight ratio of the liquid medium to the dry substrate is no more than 20: 1 , more preferably no more than 10: 1 , especially no more than 5: 1 , more especially no more than 4.5: 1 and even more especially no more than 4:1 and most especially no more than 3:1. Preferably, the weight ratio of liquid medium to the dry substrate is at least 0.1 : 1 , more preferably at least 0.5: 1 and especially at least 1 : 1. In the present invention, it is possible to use surprisingly small amounts of liquid medium whilst still achieving good treatment performance (particularly cleaning performance), which has environmental benefits in terms of water usage, waste water treatment and the energy required to heat or cool the water to the desired temperature.

Preferably, the ratio of particles to dry substrate is at least 0.1 : 1 w/w, especially at least 0.5:1 w/w and more especially at least 1 :1 w/w. Preferably, the ratio of particles to dry substrate is no more than 30: 1 , more preferably no more than 20: 1 , especially no more than 15: 1 and more especially no more than 10: 1 w/w. Preferably, the ratio of the particles to dry substrate is from 0.1 : 1 to 30: 1 , more preferably from 0.5:1 to 20:1 , especially from 1 : 1 to 15: 1 w/w and more especially from 1 :1 to 10:1 w/w.

The treatment method agitates the substrate in the presence of the solid particulate material. The agitation may be in the form of shaking, stirring, jetting and tumbling. Of these, tumbling is especially preferred. Preferably, the substrate and solid particulate material are introduced into the drum which is rotated so as to cause tumbling. The rotation can be such as to provide a centripetal force of from 0.05 to 1 G and especially from 0.05 to 0.7G. The centripetal force is preferably as calculated at the interior walls of the drum furthest away from the axis of rotation.

The solid particulate material is able to contact the substrate, suitably mixing with the substrate during the agitation. The agitation may be continuous or intermittent. Preferably, the method is performed for a period of from 1 minute to 10 hours, more preferably from 5 minutes to 3 hours and even more preferably from 10 minutes to 2 hours.

The treatment method is preferably performed at a temperature of from greater than 0°C to about 95°C, preferably from 5 to 95°C, preferably at least 10°C, preferably at least 15°C, preferably no more than 90°C, preferably no more than 70°C, and advantageously no more 50°C, no more than 40°C or no more than 30°C. Such milder temperatures provide efficiency savings in heating and energy whilst the presence of the particles improves the effectiveness of the treatment which might otherwise require higher temperatures to be effective in the same time periods. Preferably, when several batches or washloads are treated or cleaned, every treating or cleaning cycle is performed at no more than a temperature of 95°C, more preferably at no more than 90°C, even more preferably at no more than 80°C, especially at no more than 70°C, more especially at no more than 60°C and most especially at no more than 50°C, and from greater than 0°C, preferably at least 5°C, preferably at least 10°C, preferably at least 15°C, preferably from greater than 0 to 50°C, greater than 0 to 40°C, or greater than 0 to 30°C, and advantageously from 15 to 50°C, 15 to 40°C or 15 to 30°C.

It will be appreciated that the duration and temperature conditions described hereinabove are associated with the treating of an individual batch comprising at least one of said substrate(s).

Agitation of the substrates with the solid particulate material suitably takes place in said one or more discrete treating step(s) of the aforementioned treatment cycle. Thus, the duration and temperature conditions described hereinabove are preferably associated with the step of agitating said substrate(s) with solid particulate material, i.e. said one or more discrete treating step(s) of the aforementioned treatment cycle.

Preferably, the method is a method for cleaning a substrate, preferably a laundry cleaning method, preferably a method for cleaning a substrate which is or comprises a textile. Thus, preferably, a batch is a washload. Preferably the washload comprises at least one soiled substrate, preferably wherein the soiled substrate is or comprises a soiled textile. The soil may be in the form of, for example, dust, dirt, foodstuffs, beverages, animal products such as sweat, blood, urine, faeces, plant materials such as grass, and inks and paints. The cleaning procedure of an individual washload typically comprises the steps of agitating the washload with said solid particulate material in a cleaning apparatus for a cleaning cycle. A cleaning cycle typically comprises one or more discrete cleaning step(s) and optionally one or more post-cleaning treatment step(s), optionally one or more rinsing step(s), optionally one or more step(s) of separating the cleaning particles from the cleaned washload, optionally one or more extraction step(s) of removing liquid medium from the cleaned washload, optionally one or more drying step(s), and optionally the step of removing the cleaned washload from the cleaning apparatus. Where the method is a cleaning method, the substrate is preferably agitated with said solid particulate material, a liquid medium, and preferably also a treatment formulation or agent, such as a detergent composition. The detergent composition may comprise any one or more of the following components: surfactants, dye transfer inhibitors, builders, enzymes, metal chelating agents, biocides, solvents, stabilizers, acids, bases and buffers. In particular, the detergent composition may comprise one or more enzyme(s).

Where the method is a cleaning method, optional post-cleaning additives which may be present in a rinsing liquid medium include optical brightening agents, fragrances and fabric softeners.

The invention is further illustrated with reference to the following figures.

Figure 1 is a perspective view of a first embodiment of a lifter according to the present invention, in a drum also in accordance with the present invention; Figure 2 is a cross-sectional view of the lifter of figure 1 ;

Figure 3 is a side view of the lifter of figure 1 ;

Figure 4 is a perspective view of an alternative embodiment of a lifter not in accordance with the present invention;

Figure 5 is a perspective view of the embodiment of figure 4, in a drum also not in accordance with the present invention; Figure 6 is a perspective view of a second embodiment of a lifter according to the present invention, in a drum also in accordance with the present invention;

Figure 7 is a cross-sectional view of the lifter of figure 6; Figure 7a is a perspective view of an alternative version of the lifter of figure 6; Figure 7b is a cross-sectional view of the alternative version of the lifter of figure 7a;

Figure 8 is a perspective view of a third embodiment of a lifter according to the present invention, in a drum also in accordance with the present invention;

Figure 9 is a cross-sectional view of the lifter of figure 8;

Figure 10 is a perspective view of a fourth embodiment of a lifter according to the present invention, in a drum also in accordance with the present invention;

Figure 1 1 is a cross-sectional view of the lifter of figure 10;

Figure 12 is a perspective view of a fifth embodiment of a lifter according to the present invention, in a drum also in accordance with the present invention;

Figure 13 is a cross-sectional view of the lifter of figure 12;

Figure 14 is a perspective view of a sixth embodiment of a lifter according to the present invention, in a drum also in accordance with the present invention;

Figures 15a and 15b are cross-sectional views of the lifter of figure 14;

Figure 16 is a close-up view of an aperture in the lifter of figure 14; Figure 17 is a side view of the lifter of figure 14;

Figure 18 is a perspective view of the lifter of figure 14, in a drum also in accordance with the present invention; Figure 19 is a cross-sectional view of a seventh embodiment of a lifter according to the present invention;

Figure 20 is a close-up view of an aperture in the lifter of figure 19; Figure 21 is a perspective view of an eighth embodiment of a lifter according to the present invention, in a drum also in accordance with the present invention; Figure 22 is a perspective view showing a cross-section of the lifter of figure 21 ; Figure 23 is a close-up perspective view showing a cross-section of the lifter of figure 21 ; Figure 24 is a cross-sectional view of the lifter of figure 21 ;

Figure 25 is a close-up view of an aperture in the lifter of figure 21 ;

Figure 26 is a perspective view of a ninth embodiment of a lifter according to the present invention;

Figure 27 is a view of the end of the lifter of figure 26; and

Figure 28 is a close-up perspective view showing a cross-section of the lifter of figure 26.

A first embodiment of a lifter 300 according to the invention is shown in figures 1 to 3. The lifter 300 comprises a generally elongate body 302 having a base portion 304 and first and second upstanding agitation surfaces 306a, 306b. The elongate body 302 includes at its top edge 308 a substantially flat top wall 350 which joins the first and second agitation surfaces 306a, 306b. The edges between the top wall 350 and the first and second agitation surfaces 306a, 306b are rounded, though they may be bevelled or chamfered.

The elongate body 302 may be at least partially hollow and/or comprise a plurality of channels, cavities and other internal spaces as described elsewhere herein. The base portion 304, first and second upstanding agitation surfaces 306a, 306b and top wall 350 of the elongate body 302 take the shape of a trapezoidal prism.

The base portion 304, in plan, is substantially rectangular and straight (i.e. rectilinear), though it would also be possible to provide a similar shaped body portion except with a curvilinear base portion, if desired. If a top wall 350 is not desired, the edge 308 of the elongate body 302 may be configured with a curved apex at which the first and second upstanding agitation surfaces 306a, 306b meet.

In this embodiment, the upstanding agitation surfaces 306a, 306b do not touch the inner surface 316 of the drum when installed, and instead are suspended above the inner surface 316 by a plurality of fins 352 located along the elongate body 302. The base of each fin 352 includes a projection 354, which defines two shoulders 356a, 356b at opposing front and rear edges of each fin. The shoulders 356a, 356b are configured to rest on an inner cylindrical wall of a drum, as described elsewhere herein and shown in figure 2. The projections 354 of the fins 352 are configured to fit through an opening in an inner cylindrical wall of a drum (as described elsewhere herein) so as to secure the lifter 300 to the drum.

Also spaced along the length of the elongate body are a plurality of pillars 358 that are configured to secure the lifter 300 to the surface 316 of the drum, for example using fixings such as screws or rivets. The front and rear edges 360a, 360b of the fins 352 are rounded so as to present no sharp edges. Alternatively the front and rear edges 360a, 360b may be bevelled or chamfered. As will be apparent from figure 3, and as described further elsewhere herein, each fin 352 provides a sidewall for adjacent channels 310, and each channel (except for the end-most channels) have sidewalls provided by adjacent fins 352.

The channels 310 are arranged in a single row at the base portion 304 of the elongate body 302. The channels 310 can be found on both sides of the elongate body 302, and extend toward the interior of the elongate body from inlets between the fins 352 and below the first and second upstanding agitation surfaces 306a, 306b.

As mentioned, the channels 310 are enclosed on either side by the fins 352 which provide for channel side walls. Each channel 310 also includes a channel top wall 362 which curves from the respective opening downwardly toward the base portion 304 of the lifter 300 such that it guides or deflects polymer spheres as described elsewhere herein. For example, in use polymer spheres may pass from the drum through the inlets between the fins 352, through the channels 310 and out of the base portion 304 of the lifter 300 and thus out of the drum. The channel top wall 362 on one side of the body eventually meets the channel top wall 362 on the opposing side of the body, connected by a bridging portion. The configuration is entirely optional however. Indeed, it is envisaged that other than their attachment to agitation surfaces 306a, 306b at one end, the channel top wall 362 could be configured so as not connect to anything at its other end, and could simply curve downwardly to provide a lip which acts to deflect polymer spheres as described elsewhere herein.

Each channel 310 has approximately the same cross section as its respective aperture, though this need not necessarily be the case. The channel top wall 362 and each of the fins that provide the channel side walls extend into the body for 30mm, though longer or shorter walls are possible, as described elsewhere herein, depending on the geometry of the drum and the pillars and fixings that are used. The walls need not fully enclose the channel 310 nor comprise more than one wall.

Figures 6 to 11 show three embodiments of lifters 400, 500, 600 which are developments of the first embodiment shown in figures 1 to 3, and unless otherwise specified, like features are referenced with like numerals. Differences in each of the lifters 400, 500, 600 over the lifter 300 shown in figure 1 to 3 are as follows.

A second embodiment of a lifter 400 according to the invention is shown in figures 6 and 7. The lifter 400 comprises a generally elongate body 402 having a base portion 404 and first and second upstanding agitation surfaces 406a, 406b.

The elongate body 402 may be at least partially hollow and/or comprise a plurality of channels, cavities and other internal spaces as described elsewhere herein. The base portion 404 and first and second upstanding agitation surfaces 406a, 406b of the elongate body 402 take the shape of a triangular prism. The base portion 404, in plan, is substantially rectangular and straight (i.e. rectilinear), though it would also be possible to provide a similar shaped body portion except with a curvilinear base portion, if desired. The edge 408 along which the first and second upstanding agitation surfaces 406a, 406b (i.e. the edge 408 opposite the base portion 404) is curved, providing a curved apex for the elongate body 402.

The first and second upstanding surfaces 406a, 406b are formed from a metal plate having a thickness of approximately 3mm. The plate terminates below the first and second upstanding surfaces 406a, 406b at corresponding first and second inwardly pointing flanges 450a, 450b. In cross-section, the plane of each flange 450a, 450b is at an angle (i.e. inside angle) of 90 degrees to the plane of the respective upstanding surface 406a, 406b. However, the angle may be less or greater, as described in more detail below.

The base portion 404 of the lifter 400 also comprises a base plate 456, which is separate from the plate providing the first and second agitation surfaces 406a, 406b. This base plate 456 has planar surfaces 454a, 454b which oppose and are spaced apart from the inwardly pointing flanges 450a, 450b. The base plate 456 comprises one or more openings (not shown) in a lower portion of the plate to allow for particulate material passing through lifter 400 to exit the drum.

The spaced-apart flanges 450a, 450b and planar surfaces 454a, 454b define a volume therebetween which provides a plurality of channels 410 through which particulate material may pass. The orientation of the flanges 450a, 450b and planar surfaces 454a, 454b, measured in a cross-sectional plane of the lifter 400, defines the orientation of the channels and therefore the path taken by the particulate material. The orientation of the flanges 450a, 450b and planar surfaces 454a, 454b is identical, but this need not be the case.

Between the flanges 450a, 450b and planar surfaces 454a, 454b there is provided a plurality of structures 452, comprising in this case a plurality of lozenge-shaped pillars 452 extending from the planar surfaces 454a, 454b to the flanges 450a, 450b. Because the pillars are lozenge-shaped, they have no sharp edges or corners, and present only rounded surfaces to the substrates in the drum. This avoids damage. Each of the lozenge-shaped pillars 452 has a longitudinal axis, which is at an angle to the axis of the elongate body 402, and to the direction of rotation of the lifter when installed in a rotatable drum, such that the channels defined by adjacent lozenge-shaped pillars 452 define tortuous paths through which liquid and particulate material must flow when passing through. Of course, the pillars 452 need not be lozenge-shaped, and may take any suitable shape of which other variants are discussed below. The lozenge-shaped pillars may also be oriented perpendicular to the axis of the elongate body and parallel with the direction of rotation of the lifter when installed in a rotatable drum. The channels 410 are arranged in a single row at the base portion 404 of the elongate body 402. The channels 410 can be found on both sides of the elongate body 402, and extend toward the interior of the elongate body from inlets between the lozenge-shaped pillars 452 and between the flanges 450a, 450b and planar surfaces 454a, 454b. The channels 410 open into a void 458 above the base plate 456 such that particulate material (e.g. polymer spheres) may pass from the drum through the channels 410 defined between the lozenge-shaped pillars 452, through the void 458 and out of the base portion 404 of the lifter 400 and thus out of the drum. The lozenge-shaped pillars are integrally moulded from a plastics material and provided as one or more inserts fixable to the flanges 450a, 450b and planar surfaces 454a, 454b.

Figures 7a and 7b show a modified version of the embodiment of figure 7, wherein a downwardly extending central plate 460' is attached to (for example moulded to) the ends of the inwardly pointing flanges 450a', 450b'. The central plate 460' provides a deflector in the same way as the plate 156 described in connection with lifter 100 shown in figure 14, for example. A third embodiment of a lifter 500 according to the invention is shown in figures 8 and 9. The lifter 500 closely resembles the lifter 400 shown in figures 6 and 7, except that in place of the plurality of lozenge-shaped pillars is a plurality of cylindrical pillars 556. The cylindrical pillars 556 are arranged in a matrix, specifically in three rows all of which contain at least 20 pillars. Of course, more or fewer rows could be provided, and each could comprise more or fewer pillars. The pillars in the matrix shown are aligned, but again this need not be the case and the pillars may be offset from each other or placed randomly. Whilst not shown with a downwardly extending plate, a modified version of this embodiment could also include a plate attached to the ends of the inwardly pointing flanges 550a, 550b in the same way as described above in connection with lifter 400.

A fourth embodiment of a lifter 600 according to the invention is shown in figures 10 and 11. The lifter 600 closely resembles the lifter 500 shown in figures 8 and 9, except that the orientation of the flanges 650a, 650b and planar surfaces 654a, 654b is much steeper than in the third embodiment, which helps to direct particulate material toward the base and prevent particulate material from re-bounding out of the region between the flanges 650a, 650b and planar surfaces 654a, 654b (from a pillar, for example) back into the drum. In cross-section, the plane of each flange 650a, 650b is at an angle (i.e. inside angle) of 120 degrees to the plane of the respective upstanding surface 606a, 606b, though it would be possible for the angle to be between 90 degrees and 150 degrees, preferably between 100 degrees and 140 degrees, more preferably between 110 degrees and 130 degrees.

Further details of the base plate 652 can be seen in figures 10 and 11 , which also feature in the base plates 456, 552 of the embodiments of figures 6 to 9. The base plate 652 extends along the length of the elongate body 602 and has one or more openings 658 (one is shown) in the lower portion of the base plate to allow particulate material to pass from the drum, through the channels in the elongate body and through the one or more openings 658 to exit the drum. The lower portion in which the one or more openings 658 are located is curved, and forms an apex between the planar surfaces 654a, 654b.

Opposing edges 657a, 657b of the base plate 652 that extend along the base portion parallel to the plane of the agitation surfaces 606a, 606b are crimped, so as to provide flanges which, in use, lie flat against the surface of the drum and thereby provides support surfaces by which the lifter 600 may be fixed to the drum by fixings such as screws or rivets, for example. A fifth embodiment of a lifter 700 according to the invention is shown in figures 12 and 13. The lifter 700 comprises a generally elongate body 702 having a base portion 704 and first and second upstanding agitation surfaces 706a, 706b. The elongate body 702 may be at least partially hollow and/or comprise a plurality of channels, cavities and other internal spaces as described elsewhere herein. The base portion 704 and first and second upstanding agitation surfaces 706a, 706b of the elongate body 702 take the shape of a triangular prism. The base portion 704, in plan, is substantially rectangular and straight (i.e. rectilinear), though it would also be possible to provide a similar shaped body portion except with a curvilinear base portion, if desired. The edge 708 along which the first and second upstanding agitation surfaces 706a, 706b (i.e. the edge 708 opposite the base portion 704) is curved, providing a curved apex for the elongate body 702.

The agitation surfaces 706a, 706b are formed from metal sheets of thickness 3mm which terminate in inwardly pointing flanges that act as supporting surfaces 750a, 750b configured to rest on an inner cylindrical wall of a drum, as described elsewhere herein and shown in figures 12 and 13. The supporting surfaces lie flat against the surface of the drum, in use, and may be used to fix the lifter 700 to the drum by fixings such as screws or rivets, for example.

The lifter 700 comprises one or more integrally moulded inserts 752 fixable to the agitation surfaces 706a, 706b. Preferably the inserts are formed from a plastics material. To accommodate the insert 752, each of the agitation surfaces 706a, 706b comprises one or more elongate cut-outs 754 though which a portion of the inserts protrude, as described further below. Six cut-outs are shown per agitation surface 706a, 706b in figure 12, but more or fewer may be provided.

The inserts 752 comprise a plurality of channels 710, 712 coupled to a downwardly extending trunk 756 that serves two purposes. Firstly the trunk 756 is configured to fit through an opening in an inner cylindrical wall of a drum (as described elsewhere herein) so as to help locate the lifter 700 in the drum and secondly the trunk provides a chamber (not shown) into which particulate material (such as polymer spheres) can enter from a plurality of channels 710, 712 within the elongate body 702. The channels 710, 712 protrude (at least in part) through the cut-outs 754 in the agitation surfaces, though the channels could terminate flush with the surfaces and/or be overmoulded or adhered to either side of the agitation surfaces. The channels 710, 712 are arranged in rows along the elongate body 702, including (but not limited to) a first, lower row 710 that is closest to the base portion 704 and a second, upper row 712 that is furthest from the base portion 704. It will be appreciated that more rows may be provided, for example three, four, five or six rows, depending on the size of the drum and, consequently, the height of the lifter.

The channels can be found on both sides of the elongate body 702, and extend toward the interior of the elongate body from apertures in the inserts, specifically apertures at the end of the channels that couple to the cut-outs 754 in the agitation surfaces 706a, 706b. In the embodiment shown in figures 12 and 13, the channels are oriented downwardly toward the base portion, but the precise angle of orientation may vary depending on the specific implementation. Alternatively, the channels may extend parallel to the base portion, i.e. substantially parallel to the cylindrical surface of a drum, in use. The channels 710, 712 open into the chamber in the trunk 756 such that polymer spheres may pass from the drum through the apertures in the insert coupled to the cut-outs 754 in the first and second upstanding agitation surfaces 706a, 706b, through the channels 710, 712, through the chamber and out of the base portion 704 of the lifter 700 and thus out of the drum.

The channels 710, 712 are tubular with a stadium-shaped cross-section. The apertures of the channels 710, 712 in the first and second rows have the same size and shape, and are aligned not only along the length of the elongate body 702 in rows but also in columns such that an aperture in the first, lower row 710 is directly beneath an aperture in the second, upper row 712.

Each aperture of the channels 710, 712 is in the shape of a slot. The aperture is approximately rectangular and would be a precise rectangle shape but for the rounded corners which cause it to have a stadium shape with straight upper and lower sides with semi-circular ends. Alternatively the slot may have four straight sides (two long upper and lower sides, and two short sides perpendicular to those) with rounded corners which cause it to have a rounded rectangle shape. The edges of each aperture are not sharp but bevelled. Alternatively they may be chamfered or rounded. Each channel 710, 712 has approximately the same cross section as its respective aperture, though this need not necessarily be the case. Each channel 710, 712 has upper, lower and opposing side channel walls which extend into the body for 20mm, though longer or shorter walls are possible, as described elsewhere herein, and the walls need not necessarily fully enclose the channel 710, 712 nor comprise more than one wall.

A sixth embodiment of a lifter 100 according to the invention is shown in figures 14 to 18. The lifter 100 comprises a generally elongate body 102 having a base portion 104 and first and second upstanding agitation surfaces 106a, 106b. The elongate body 102 may be at least partially hollow and/or comprise a plurality of channels, cavities and other internal spaces as described elsewhere herein. The base portion 104 and first and second upstanding agitation surfaces 106a, 106b of the elongate body 102 take the shape of a triangular prism. The base portion 104, in plan, is substantially rectangular and straight (i.e. rectilinear), though it would also be possible to provide a similar shaped body portion except with a curvilinear base portion, if desired. The edge 108 along which the first and second upstanding agitation surfaces 106a, 106b (i.e. the edge 108 opposite the base portion 104) is curved, providing a curved apex for the elongate body 102.

The base portion 104 comprises supporting surfaces 150a, 150b configured to rest on an inner cylindrical wall of a drum, as described elsewhere herein and shown in figure 14. Extending downwardly from the supporting surfaces 150a, 150b is a trunk 152 that serves two purposes. Firstly the trunk 152 is configured to fit through an opening in an inner cylindrical wall of a drum (as described elsewhere herein) so as to help secure the lifter 100 to the drum and secondly the trunk provides a chamber 154 into which particulate material (such as polymer spheres) can enter from a plurality of channels 110, 112 within the elongate body 102.

The channels are arranged in rows along the elongate body 102, including (but not limited to) a first, lower row 110 that is closest to the base portion 104 and a second, upper row 1 12 that is furthest from the base portion 104. It will be appreciated that more rows may be provided, for example three, four, five or six rows, depending on the size of the drum and, consequently, the height of the lifter. The channels can be found on both sides of the elongate body 102, and extend toward the interior of the elongate body from apertures in the first and second upstanding agitation surfaces 106a, 106b. In the embodiment shown in figures 14 to 18, the channels extend parallel to the base portion, i.e. substantially parallel to the cylindrical surface of a drum, in use. The channels 110, 1 12 open into the chamber 154 such that polymer spheres may pass from the drum through the apertures in the first and second upstanding agitation surfaces 106a, 106b, through the channels 1 10, 1 12, through the chamber 154 and out of the base portion 104 of the lifter 100 and thus out of the drum.

Within the chamber 154 is a metal plate 156. The plate need not be metal, but it is advantageous for the plate to have a superior hardness compared with other materials of the body 102, for example, because it must resist the impact from fast moving polymer spheres passing through channels 110, 1 12. It is preferable for the plate to be resistant to corrosion and as such it could be made from e.g. stainless steel or be plated. The purpose of the metal plate 156 is to redirect the polymer spheres from a path that is substantially parallel with the cylindrical surface of a drum to a path that is substantially perpendicular to it. In other words, in use, the solid particulate material (e.g. polymer spheres) collides with the metal plate 156 and then drops or is forced (by centrifugal force) out of the chamber 154 and through an opening in the drum.

The metal plate 156 divides the chamber 154. The plate 156 extends along the length of the body 102 and is fixed to the body 102 by being embedded in a roof 157 of the chamber 154 and secured by one or more screws passing through the agitation surfaces 106a, 106b in the body 102. Viewing the cross-section of the body in figure 15a, the plate 156 is located in the centre of the body 102, about which the body 102 is symmetrical.

Most of the apertures of the channels 1 10, 112 in the first and second rows have the same size and shape, and are aligned not only along the length of the elongate body 102 in rows but also in columns such that an aperture in the first, lower row 1 10 is directly beneath an aperture in the second, upper row 112. Periodically spaced along the length of the elongate body 102 are pairs of adjacent apertures 158a, 158b and 160a, 160b in the first, lower row 1 10 that are shorter than the rest. Between each pair is a larger distance than exists between other adjacent apertures in the row, and this is to accommodate fixings such as screws or rivets which secure the lifter 100 to the cylindrical surface 116 of the drum. Preferably the distance is at least 5mm, preferably 7.5mm, preferably 10mm, preferably 15mm, preferably 20mm, but ultimately depends on manufacturer and drum design.

Each aperture of the channels 1 10, 1 12 is in the shape of a slot. The aperture is approximately rectangular and would be a precise rectangle shape but for the rounded corners which cause it to have a stadium shape with straight upper and lower sides with semi-circular ends. Alternatively the slot may have four straight sides (two long upper and lower sides, and two short sides perpendicular to those) with rounded corners which cause it to have a rounded rectangle shape. The edges of each aperture are not sharp but bevelled. Alternatively they may be chamfered or rounded. As shown in figure 16, the length of the preferred aperture is 25.1 mm, but the length may be between 10mm and 40mm, preferably 15mm and 35mm, preferably between 20mm and 30mm. The height of the preferred aperture is 10.6mm, but the height may be between 5mm and 15mm, preferably between 7.5 and 12.5mm.

Each channel 110, 112 has approximately the same cross section as its respective aperture, though this need not necessarily be the case. Each channel 110, 112 has upper, lower and opposing side channel walls which extend into the body for 10mm, though longer or shorter walls are possible, as described elsewhere herein, and the walls need not necessarily fully enclose the channel 1 10, 1 12 nor comprise more than one wall. The length of the channel may depend on whether it is in the upper row or lower row of channels. As shown in figure 15b, the length of the upper channel is 20mm and the length of the lower channel is 26.7mm. In general, the length may be between 5mm and 75mm, preferably between 7.5mm and 50mm, preferably between 10mm and 40mm, preferably between 15mm and 30mm.

Each of the features (individually and in combination) of rounded slot corners, bevelled, chamfered or rounded slot edges and extension of one or more walls of the channel into the elongate body by a certain distance (e.g. at least 5mm) has a particular effect of reducing damage to substrates being treated. In particular, by avoiding where possible sharp corners, edges and thin sections that could be prone to catching substrates being treated, fewer substrates suffer damage including tears and broken or lost buttons. Alternatively (or additionally), where damage does occur it is less pronounced.

Figures 19 and 20 show the cross section of a similar lifter 800, according to a seventh embodiment of the invention, to that shown in figures 14 to 18, and unless otherwise specified, like features are referenced with like numerals. Differences in lifter 800 over the lifter 100 shown in figures 14 to 18 are as follows.

Instead of a rounded apex at the top edge of the lifter, as with the previous embodiment, the lifter 800 in the embodiment of figure 19 includes at its top edge 808 a substantially flat top wall 850 which joins the first and second agitation surfaces 806a, 806b. The edges between the top wall 850 and the first and second agitation surfaces 806a, 806b are rounded, though they may bevelled or chamfered. As shown in figure 19, the length of the upper channel of the seventh embodiment is 19.3mm and the length of the lower channel is 29.9mm. Again, in general, the length may be between 5mm and 75mm, preferably between 5mm and 50mm, preferably between 10mm and 40mm, preferably between 15mm and 30mm.

As shown in figure 20, the length of the preferred aperture is 27.3mm, but the length may be between 10mm and 40mm, preferably 15mm and 35mm, preferably between 20mm and 30mm. The height of the preferred aperture is 10.5mm, but the height may be between 5mm and 15mm, preferably between 7.5 and 12.5mm.

Figures 21 to 25 show an eighth embodiment of a lifter 200 according to the invention. Lifter 200 is similar to the embodiment 100 shown in figures 14 to 18, and unless otherwise specified like features are referenced with like numerals. Differences in lifter 800 over the lifter 100 shown in figures 14 to 18 are as follows.

As with the seventh embodiment in figures 19 and 20, instead of a rounded apex at the top edge of the lifter, the lifter 200 in the embodiment of figure 21 includes at its top edge 208 a substantially flat top wall 250 which joins the first and second agitation surfaces 206a, 206b. The edges between the top wall 250 and the first and second agitation surfaces 206a, 206b are rounded, though they may bevelled or chamfered.

The channels 210, 212, 214 are likewise arranged along the elongate body 202 in a first, lower row 210 and a second, upper row 212. The apertures of the channels 210, 212 are aligned not only along the length of the elongate body 202 in rows but also in columns such that an aperture in the first, lower row 210 is directly beneath an aperture in the second, upper row 212. Unlike the embodiment of figures 14 to 18, all of the apertures of channel 210, 212 have the same size and shape. Instead of providing periodically spaced shorter apertures in the first, lower row of apertures to accommodate fixings such as screws or rivets, entire columns of adjacent apertures 252a, 252b are periodically spaced apart from each other by a greater distance than exists between other adjacent columns. Preferably the distance is at least 5mm, preferably 7.5mm, preferably 10mm, preferably 15mm, preferably 20mm. This allows for longer fixings to be provided, and is an arrangement which may equally be provided in respect of the sixth embodiment. In addition to the first and second rows of channels 210 and 212, the embodiment shown in figures 21 to 24 provides a third row of channels 214, likewise having apertures, which is further from the base portion than both of the first and second rows 210, 212. The apertures in the third row 214 are the same size and shape as the apertures in each of the first and second rows 210, 212, and aligned with each other along the row as well as with respective apertures in the first and second rows in columns. It will be appreciated that more rows may be provided, for example three, four, five or six rows, depending on the size of the drum and, consequently, the height of the lifter.

The third row of channels 214 is spaced further apart from the second row than the second row 212 is spaced from the first row 210. Preferably the distance is at least 5mm, preferably 7.5mm, preferably 10mm, preferably 15mm, preferably 20mm. Preferably the third row of channels 214 is spaced apart from the second row 212 by the same distance between the aforesaid entire columns of adjacent apertures 252a, 252b.

As with the sixth embodiment, channels are tubular with a stadium-shaped cross-section. The apertures are likewise shaped thus.

As shown in figure 23, the channels can be found on both sides of the elongate body 202, and extend toward the interior of the elongate body from apertures in the first and second upstanding agitation surfaces 206a, 206b. In the embodiment shown in figures 23 and 24, the channels extend parallel to the base portion, i.e. substantially parallel to the cylindrical surface of a drum, in use.

Unlike the lifter 100 of the sixth embodiment, the lifter 200 does not have a central metal plate to deflect solid particulate matter. Instead, each channel 210, 212, 214 is provided, at its inner end opposite the aperture in the agitation surface 206a, 206b with a downwardly oriented deflector 254 formed in its top wall, configured such that solid particulate material passing through the channels 210, 212 comes into contact with the deflectors 254 and is directed toward the base portion 204, in particular to a chamber in the trunk and thence through an opening in the base portion. It will be appreciated that in some designs (including that pictured in figures 23 and 24) the top wall of a lower channel forms the bottom wall of a channel immediately above it. Thus, just as the top wall of a lower channel is downwardly oriented, so too is the bottom wall of a channel above. Thus, should the particulate material come into contact with the bottom wall of a channel, for instance through gravity or centrifugal force, it is directed toward the chamber in the trunk and thence through an opening in the base portion. It will likewise be appreciated that in some designs, the lower wall of a channel will not extend as far into the elongate body as the upper wall having the deflector, such that the passage of solid particulate material that is deflected by the deflector is not blocked by a lower wall located immediate beneath the deflector.

As shown in figure 24, the length of the upper channel of the eighth embodiment is 17.4mm, the length of the middle channel is 31 mm and the length of the lower channel is 37.7mm. Again, in general, the length may be between 5mm and 75mm, preferably between 5mm and 50mm, preferably between 10mm and 40mm.

As shown in figure 25, the length of the preferred aperture is 26mm, but the length may be between 10mm and 40mm, preferably 15mm and 35mm, preferably between 20mm and 30mm. The height of the preferred aperture is 10.6mm, but the height may be between 5mm and 15mm, preferably between 7.5 and 12.5mm.

Each of the features (individually and in combination) of rounded corners on the fins, and extension of the channel into the elongate body by a certain distance (e.g. at least 5mm) has a particular effect of reducing damage to substrates being treated. In particular, by avoiding where possible sharp corners, edges and thin sections, such as appear in the lifter 900 not according to the invention that is shown in figures 4 and 5, which could be prone to catching substrates being treated, fewer substrates suffer damage including tears and broken or lost buttons. Alternatively (or additionally), where damage does occur it is less pronounced. Figures 26 to 28 show a ninth embodiment of a lifter 1000 according to the invention. Lifter 1000 has similarities to embodiments described above, and unless otherwise specified like features are referenced with like numerals.

As with lifter 700 shown in figures 12 and 13, lifter 1000 comprises a generally elongate body 1002 having a base portion 1004 and first and second upstanding agitation surfaces 1006a, 1006b.

The elongate body 1002 may be at least partially hollow and/or comprise a plurality of channels, cavities and other internal spaces as described elsewhere herein. The base portion 1004 and first and second upstanding agitation surfaces 1006a, 1006b of the elongate body 1002 take the shape of a triangular prism. The base portion 1004, in plan, is substantially rectangular and straight (i.e. rectilinear), though it would also be possible to provide a similar shaped body portion except with a curvilinear base portion, if desired.

As with the lifter 800 shown in figure 19 and 20, for example, the lifter 1000 includes at its top edge 1008 a substantially flat top wall 1050 which joins the first and second agitation surfaces 1006a, 1006b. The edges between the top wall 1050 and the first and second agitation surfaces 1006a, 1006b are rounded, though they may bevelled or chamfered. Alternatively, as with lifter 700 shown in figures 12 and 13, for example, the edge 1008 along which the first and second upstanding agitation surfaces 1006a, 1006b meet may be curved, providing a curved apex for the elongate body 1002.

The agitation surfaces 1006a, 1006b are formed from metal sheets of thickness 3mm which terminate in inwardly pointing flanges that act as supporting surfaces 1051 a, 1051 b configured to rest on an inner cylindrical wall of a drum, as described elsewhere herein. The supporting surfaces lie flat against the surface of the drum, in use, and may be used to fix the lifter 1000 to the drum by fixings such as screws or rivets, for example.

The lifter 1000 comprises one or more integrally moulded inserts 1052 fixable to the agitation surfaces 1006a, 1006b. Preferably the inserts are formed from a plastics material. To accommodate the insert 1052, each of the agitation surfaces 1006a, 1006b comprises one or more cut-outs though which a portion of the inserts protrude, as described further below.

Each insert comprises a planar wall 1054, which when fixed to the agitation surface 1006a, 1006b is flush with the surface to which it is fixed. This is achieved by shaping the metal sheet forming the agitation surface such that it provides a recessed portion of identical depth to the thickness of the planar wall 1054 of the insert 1052. Together, the agitation surfaces 1006a, 1006b formed from the shaped metal sheet and the integrally molded inserts which locate within the recessed portion provide the elongate body 1002 of the lifter 1000 with its triangular prism shape, similar to the entirely integrally moulded lifter 200 shown in figures 21 and 22. An advantage of lifter 1000 is that existing lifters not according to the invention (such as lifter 900 shown in figures 4 and 5) and formed from metal sheets may be retrofitted with inserts to provide a lifter according to the invention.

The channels 1010, 1012 of the lifter 1000 are similar to those found in lifter 200 shown in figures 21 to 25. The channels can be found on both sides of the elongate body 1002, and extend toward the interior of the elongate body from apertures in the planar walls 1054. In the embodiment shown in figures 26 to 28, the channels extend parallel to the base portion, i.e. substantially parallel to the cylindrical surface of a drum, in use. The channels 1010, 1012 are tubular with a stadium-shaped cross-section. The apertures found in the planar wall 1054 of the insert are likewise shaped thus.

As with lifter 200 shown in figures 21 to 25, each channel 1010, 1012 is provided, at its inner end opposite the aperture in the planar wall 1054 with a downwardly oriented deflector 1055 formed in its top wall, configured such that solid particulate material passing through the channels 1010, 1012 comes into contact with the deflectors 1055 and is directed toward the base portion 1004.

As with lifter 200 shown in figures 21 to 25, the lower wall of the channels does not extend as far into the elongate body as the corresponding upper wall having the deflector, such that the passage of solid particulate material that is deflected by the deflector is not blocked by a lower wall located immediate beneath the deflector.

Lifter 1000 comprises two rows of channels, but more could be provided as in previous embodiments. The apertures of the channels are aligned, but as with previous embodiments may be offset from each other. All apertures of the channels are the same size and shape, but as with some previous embodiments this need not be the case.

As mentioned above, the agitation surfaces 1006a, 1006b comprises one or more (in this case a plurality) of cut-outs, each of which is sized such that a channel 1010, 1012 can extend therethrough. In the illustrated embodiment, each cut-out accommodates one channel. However, each cut-out could be sized to accommodate two or more adjacent channels, either adjacent horizontally, adjacent vertically or both. The agitation surfaces 1006a, 1006b could instead be provided with one or more larger elongate cut-outs that accommodate a sub-set or all of channels of the inserts.

Features described herein in conjunction with a particular aspect or example of the disclosure are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. As used herein, the words "a" or "an" are not limited to the singular but are understood to include a plurality, unless the context requires otherwise.

Claims

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

The lifter of claim 1 , wherein the plurality of structures defines at least a first row of inlets.

The lifter of claim 1 or claim 2, wherein the inlets in at least one of the sides of the elongate body are located underneath the one or more agitation surfaces, between the one or more agitation surfaces and the base portion.

The lifter of any of claims 1 to 3, wherein the inlets in at least one of the sides of the elongate body are provided by apertures in the one or more agitation surfaces, preferably wherein at least one of the one or more agitation surfaces are planar surfaces.

The lifter of claim 4, wherein the plurality of structures are channels, preferably tubular channels, extending from said apertures, each channel being at least partially enclosed by one or more one channel walls.

The lifter of claim 5, wherein the one or more channel walls extend from the aperture of the respective channel for a distance of at least 4mm, preferably at least 5mm, more preferably at least 7.5mm, more preferably at least 10mm, more preferably at least 15mm, more preferably at least 20mm, more preferably at least 25mm, more preferably at least 30mm.

7. The lifter of claim 5 or claim 6, wherein the one or more channel walls includes at least a channel base wall, being the channel wall which is closest to the base portion of the elongate body, and preferably one or more channel side walls extending perpendicularly to the channel base wall, preferably wherein there are two channel side walls either side of the channel base wall and opposing each other.

8. The lifter of any one of claims 4 to 7, wherein at least some of the apertures in the one or more agitation surfaces have an edge and at least part, more preferably, all of at least some of those edge(s) of each aperture are bevelled, chamfered or rounded.

9. The lifter of any one of claims 4 to 8, wherein the elongate body extends along an axis and preferably each aperture has a substantially rectangular shape, preferably a rounded rectangular shape, preferably a stadium shape, with a long edge parallel to the axis.

10. The lifter of claim 9, when dependent on claim 2, wherein the long edges of the apertures of the first row of inlets are aligned.

1 1. The lifter of claim 9 or claim 10, comprising first and second rows of apertures, the second row being further away from the base portion than the first row.

12. The lifter of claim 1 1 , wherein each aperture in the first and second rows has opposing long edges and short edges, and wherein the apertures are aligned along columns such that the short edges of the apertures in the first row are aligned with corresponding short edges of the apertures in the second row.

13. The lifter of claim 1 1 , wherein each aperture in the first and second rows has opposing long edges and short edges, and wherein respective apertures in the first and second rows are offset from each other such that the short edges of the apertures in the first row are not aligned with corresponding short edges of the apertures in the second row.

14. The lifter of claim 1 1 , wherein each aperture in the first and second rows has opposing long edges and short edges, and wherein the first and second rows of apertures are spaced apart from each other in a direction parallel with the short edges of the apertures by a distance of at least 3mm, preferably 4mm, preferably 5mm, preferably 7.5mm, preferably 10mm, preferably 15mm, preferably 20mm, preferably 25mm, preferably 30mm, preferably 40mm.

15. The lifter of claim 13 or claim 14 wherein the inlets in adjacent rows are staggered, and preferably the staggering is such that the centre of each inlet in one row is equidistant between the centres of two adjacent inlets in an adjacent row.

16. The lifter of any of claims 5 to 15, when dependent on claim 5, wherein each agitation surface is at least partially provided by a plate, and wherein the plurality of channels are provided by one or more inserts coupled to the one or more plates.

17. The lifter of any of claims 5 to 15, when dependent on claim 5, wherein the elongate body comprises an integral moulding which provides the one or more agitation surfaces and defines the plurality of channels.

18. The lifter of claim 17, wherein the integral moulding is provided in first and second symmetrical portions, each comprising at least one agitation surface and defining one set of a plurality of tubular channels extending from apertures in said at least one agitation surface.

19. The lifter of claim 17, wherein the integral moulding provides opposing first and second agitation surfaces and defines two sets of a plurality of tubular channels, each extending from apertures in the respective opposing agitation surfaces.

20. The lifter of claim 18, wherein the first and second symmetrical portions are connected together by at least one fixing means.

21. The lifter of any one of claims 5 to 20, when dependent on claim 5, wherein the plurality of channels are orthogonal to the agitation surface.

22. The lifter of any one of claims 5 to 20, when dependent on claim 5, wherein the plurality of channels are orthogonal to a plane of symmetry of the elongate body and/or parallel to the base portion.

23. The lifter of any one of claims 1 to 3, wherein the plurality of structures comprises a plurality of spaced-apart fins, lozenges or cylinders, each inlet occupying a space between two adjacent structures.

24. The lifter of claim 23, wherein the agitation surface terminates in an angled wall extending into the body of the lifter, and the plurality of structures occupy a region between the wall and the base portion.

25. The lifter of claim 24, wherein the plurality of structures is a plurality of fins or lozenges, wherein each fin or lozenge extends the length of the region between the angled wall and the base portion.

26. The lifter of claim 24, wherein the plurality of structures is a plurality of cylinders, wherein the cylinders are arranged in a plurality of spaced-apart rows distributed along the length of the region between the angled wall and the base portion.

27. The lifter of any one of claims 24 to 26, wherein the angled wall is at an angle of 90 degrees or more to the agitation surface, preferably at an angle of 100 degrees or more, preferably at an angle of 1 10 degrees or more at an angle of 120 degrees or more.

28. The lifter of any preceding claim, wherein the base is rectangular in plan.

29. The lifter of any preceding claim, the base portion having one or more support surfaces for resting on the cylindrical surface of the drum.

30. The lifter of any preceding claim, further comprising one or more deflectors positioned within the body to at least partially intersect the flow path such that at least some particulate material passing through the passageways comes into contact with the one or more deflectors and is thereby directed toward the base.

31 The lifter of claim 30, wherein the deflector takes the form of a plate passing through the body, preferably occupying a plane of symmetry of the elongate body, wherein the one or more channels are oriented toward the plate.

32. The lifter of claim 30, when dependent on any of claims 24 to 27, wherein the deflector comprises the angled wall.

33. The lifter of claim 31 , when dependent on any one of claims 5 to 22, wherein each channel has one or more channel walls, and at least some of the channel walls comprise a channel base wall, the end of the channel base wall being spaced apart from the plate to provide a gap between the channel base wall and the plate through which deflected particulate material may pass toward the base.

34. The lifter of any one of claims 31 or 33, wherein the plate is a metal plate and the elongate body is made from a plastics material.

35. The lifter of claim 30, when dependent on any one of claims 5 to 22, wherein each channel has one or more channel walls, and at least some of the channel walls comprise a channel top wall, being the channel wall which is furthest away from the base portion of the elongate body, and wherein the one or more deflectors comprise a plurality of deflectors each comprising a lip extending from the channel top wall toward the base.

36. The lifter of claim 35, wherein the channel walls further comprise a channel base wall, substantially opposing the channel top wall, the channel top wall extending further in the direction of the channel than the channel base wall to provide a gap beneath the lip in the channel top wall through which deflected particulate material may pass toward the base.

37. The lifter of any one of claims 30 to 36, wherein the deflector is provided by a curved or angled wall which curves or is angled toward the base portion such that at least some particulate material passing through the channels is guided by the curved or angled wall and is thereby directed toward the base.

38. The lifter of any preceding claim wherein the elongate body and the arrangement of one or more passageways and corresponding inlets in the body is symmetrical in a plane passing through the elongate body along its length.

39. A rotatable drum for use in an apparatus for use in the treatment of substrates with a solid particulate material, the rotatable drum having an end wall and an inner cylindrical wall comprising perforations and at least one opening, and at least one lifter according to any preceding claim, wherein the elongate body of the lifter extends from the end wall, and wherein the lifter is positioned on the inner cylindrical wall over an opening to allow particulate material to pass from the interior of the drum through the one or more passageways in the at least one lifter and out of the at least one opening, wherein each of the perforations has a largest dimension that is smaller than the smallest linear dimension of the inlets in the lifter.

40. The rotatable drum of claim 39, comprising two, three, four, five or six lifters according to any of claims 1 to 38.

41. The rotatable drum of claim 39 or 40, wherein each of the perforations has a largest dimension smaller than the dimensions of the solid particulate material so as to permit passage of fluids through said perforations, particularly from the interior of said drum, but to prevent egress of said solid particulate material through said perforations.

42. The rotatable drum of claims 39 to 41 , wherein the one or more lifters are removably attachable to the drum.

43. 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 according to any of claims 39 to 42; and

access means for introducing said substrates into said drum.

44. The apparatus of claim 43, 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 formulations or treatment agents into and out of the tub.

45. An apparatus according to claim 43 or claim 44 further comprising a seal between the access means and the drum such that, in use, solid particulate material is not able to leave the drum through the access means.

46. An apparatus according to any of claims 43 to 45 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.

47. An apparatus according to any of claims 43 to 46 wherein said treatment of substrates with solid particulate material is in the presence of a liquid medium and/or one of more treatment formulations or treatment agents.

48. An apparatus according to any of claims 43 to 47 which comprises said solid particulate material.

49. An apparatus according to any of claims 43 to 48 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 20 mm, preferably from 5mm to 10mm; (v) an average density of at least about 1 g/cm³, preferably at least about 1.1 g/cm³, more preferably at least about 1.2 g/cm³, even more preferably at least about 1.25 g/cm³, even more preferably at least about 1.3 g/cm³; and/or (vii) an average density of no more than about 3 g/cm³, preferably no more than about 2.5 g/cm³, .

50. An apparatus according to any of claims 43 to 49 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 or polyethylene, and preferably a polyamide or a polyamide selected from nylon 6 or nylon 6,6.

51. An apparatus according to any of claims 43 to 50 wherein the particles of the solid particulate are, or comprise, metal, alloy, ceramic and glass particles.

52. An apparatus according to any of claims 43 to 51 wherein the particles of the solid particulate material are spheroidal and/or ellipsoidal.

53. A method of treating a substrate using solid particulate material in an apparatus for use in the treatment of substrates, the apparatus having a rotatable drum having one or more lifters, the method comprising the steps of: rotating the rotatable drum to treat the substrate by causing contact between the substrate and both the solid particulate material and the one or more lifters; and removing the particulate material from the drum by passing the particulate material through one or more passageways passing through the lifter, each defining at least part of a flow path between a respective inlet in a side of the lifter and one or more openings in the cylindrical wall of the drum with which the lifter is aligned; wherein the step of causing contact between the substrate and the one or more lifters comprises contacting at least a portion of the substrate with at least a portion of one of a plurality of structures defining the inlets in a side of the lifter, wherein at least one surface of each structure extends from the inlet into the body of the lifter for a distance of at least 5mm.

54. The method of claim 53, wherein each perforation has a largest dimension smaller than the dimensions of the solid particulate material so as to permit passage of fluids through said perforations into and out of the drum, but to prevent egress of said solid particulate material through said perforations.

55. A method of treating a substrate, the method comprising agitating the substrate in an apparatus according to any of claims 48 to 52 with the solid particulate material.

56. A method according to claim 55 wherein the solid particulate material is re-used in further treatment procedures according to the method.

57. A method according to claim 55 or 56 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 the solid particulate material, wherein said method further comprises the steps of:

(a) collecting at least a portion of the solid particulate material in a storage means;

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

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

58. A method according to any of claims 55 to 57 wherein the method comprises agitating the substrate with solid particulate material and a liquid medium, preferably wherein the liquid medium is aqueous.

59. A method according to any of claims 55 to 58 wherein the method comprises agitating the substrate with said solid particulate material and a treatment formulation or treatment agent.

60. A method according to any of claims 55 to 59 wherein the substrate is or comprises a textile.

61. A method according to claim 60 wherein the treating of said substrate is or comprises cleaning, coloration, bleaching, abrading, desizing or ageing, or other textile or garment finishing process.

62. A method according to claim 61 for cleaning a substrate wherein the substrate is a soiled substrate.

63. A method according to any of claims 55 to 62 wherein the substrate is or comprises an animal skin substrate.

64. A method according to claim 63 wherein the treating of an animal skin substrate is a tannery process.

65. A method according to claim 64, wherein the tannery process is or comprises tanning, re-tanning, fat-liquoring, soaking, liming, unhairing, deliming, pickling or combinations thereof.