IMPROVED CLEANING APPARATUS AND METHOD
Field of the Invention
The present invention relates to the aqueous cleaning of substrates using a cleaning
system which requires the use of only limited quantities of energy, water and detergent.
Most particularly, the invention is concerned with the cleaning of textile fibres and fabrics
by means of such a system, and provides an apparatus adapted for use in this context.
Background to the Invention
Aqueous cleaning processes are a mainstay of both domestic and industrial textile fabric
washing. On the assumption that the desired level of cleaning is achieved, the efficacy
of such processes is usually characterised by their levels of consumption of energy,
water and detergent. In general, the lower the requirements with regard to these three
components, the more efficient the washing process is deemed. The downstream effect
of reduced water and detergent consumption is also significant, as this minimises the
need for disposal of aqueous effluent, which is both extremely costly and detrimental to
the environment.
Such washing processes involve aqueous submersion of fabrics followed by soil
removal, aqueous soil suspension, and water rinsing. In general, within practical limits,
the higher the level of energy (or temperature), water and detergent which is used, the
better the cleaning. The key issue, however, concerns water consumption, as this sets
the energy requirements (in order to heat the wash water), and the detergent dosage (to
achieve the desired detergent concentration). In addition, the water usage level defines
the mechanical action of the process on the fabric, which is another important
performance parameter; this is the agitation of the cloth surface during washing, which
plays a key role in releasing embedded soil. In aqueous processes, such mechanical
action is provided by the water usage level in combination with the drum design for any
particular washing machine. In general terms, it is found that the higher the water level
in the drum, the better the mechanical action. Hence, there is a dichotomy created by
the desire to improve overall process efficiency (i.e. reduce energy, water and detergent
consumption), and the need for efficient mechanical action in the wash. For domestic
washing in particular there are defined wash performance standards specifically
designed to discourage the use of such higher levels in practice, in addition to the
obvious cost penalties which are associated with such usage.
Current efficient domestic washing machines have made significant strides towards
minimising their consumptions of energy, water and detergent. EU Directive 92/75/CEE
sets a standard which defines washing machine energy consumption in kWh/cycle
(cotton setting at 60°C), such that an efficient domestic washing machine will typically
consume < 0.19 kWh/kg of washload in order to obtain an 'A' rating. If water
consumption is also considered, then 'A' rated machines use < 9.7 litres/kg of washload,
whilst the most efficient modern machines are now capable of using even less water -
e.g. model number F1480FD6 manufactured by LG (see www.lg.com ) . This machine
typically uses 63 litres for a 9 kg washload, i.e. 7 litres/kg.
Detergent dosage is then driven by manufacturer recommendations but, again, in the
domestic market, for a concentrated liquid formulation, a figure of 35 ml (or 37 g) for a 4-
6 kg washload in soft and medium hardness water, increasing to 52 ml (or 55 g) for a 6-
8 kg washload (or in hard water or for very dirty items) is typical (see, for example,
Unilever pack dosage instructions for Persil® Small & Mighty). Hence, for a 4-6 kg
washload in soft/medium water hardness, this equates to a detergent dosage of 7.4-9.2
g/kg whilst, for a 6-8 kg washload (or in hard water or for very dirty items), the range is
6.9-9.2 g/kg.
Energy, water and detergent consumptions in the industrial washing process (washerextractors)
are considerably different, however, and usages of energy and water are less
constrained in such environments, since these are principal factors in reducing cycle
time - which is, of course, more of a consideration than in the domestic scenario. There
is a similar pressure on detergent levels, however, but this is mostly due to a desire to
reduce cost.
Thus, it can be taken from the above discussion that the performance levels which set
the highest standard for an efficient fabric washing process are an energy consumption
of < 0.1 9 kWh/kg, a water usage of approximately 7 litres/kg, and a detergent dosage of
approximately 8 g/kg. However, as already mentioned, it is becoming increasingly
difficult to reduce the water (and, hence, energy and detergent) levels in a purely
aqueous process, due to the minimum requirement to wet the fabric thoroughly, the
need to provide sufficient excess water to suspend the soil removed in an aqueous
liquor and, finally, the need to rinse the fabric.
Heating of the wash water is then the principal use of energy, and a minimum level of
detergent becomes necessary in order for an effective concentration to be reached at
the operating wash temperature. If a means to improve mechanical action could be
achieved without increasing the water level used, then the aqueous wash process could
become significantly more efficient (i.e. yield further reductions in energy, water and
detergent consumption). It should be noted that mechanical action itself has a direct
effect on the detergent level, since the greater the level of soil removal which is achieved
through physical force, the less that is required of the detergent chemistry. However,
increasing the mechanical action in a purely aqueous washing process has certain
associated drawbacks. Fabric creasing readily occurs in such processes, and this acts
to concentrate the stresses from mechanical action at each crease, resulting in localised
fabric damage. Prevention of such fabric damage (i.e. fabric care) is of primary concern
to the domestic consumer and the industrial user.
Various different approaches to the development of new cleaning technologies have
been reported in the prior art, including methods which rely on electrolytic cleaning or
plasma cleaning, in addition to approaches which are based on ozone technology,
ultrasonic technology or steam technology. Thus, for example, WO-A-2009/021 9 19
teaches a fabric cleaning and disinfection process which utilises UV-produced ozone
along with plasma. An alternative technology involves cold water washing in the
presence of specified enzymes, whilst a further approach which is particularly favoured
relies on air-wash technology and, for example, is disclosed in US-A-2009/00901 38. In
addition, various carbon dioxide cleaning technologies have been developed, such as
the methods using ester additives and dense phase gas treatments which are described
in US-B-7481 893 and US-A-2008/0223406, although such methods generally find
greater applicability in the field of dry cleaning. Many of these technologies are,
however, technically complex and not readily suited to domestic applications, in
particular.
In the light of the challenges which are associated with aqueous washing processes, the
present inventors have previously devised a new approach to the problem, which is
technologically straightforward, and yet still allows the deficiencies demonstrated by the
methods of the prior art to be overcome. The method which is provided eliminates the
requirement for the use of large volumes of water, but is still capable of providing an
efficient means of cleaning and stain removal, whilst also yielding economic and
environmental benefits.
Thus, in WO-A-2007/1 28962 there is disclosed a method and formulation for cleaning a
soiled substrate, the method comprising the treatment of the moistened substrate with a
formulation comprising a multiplicity of polymeric particles, wherein the formulation is
free of organic solvents. Preferably, the substrate is wetted so as to achieve a substrate
to water ratio of between 1:0.1 to 1:5 w/w, and optionally, the formulation additionally
comprises at least one cleaning material, which typically comprises a surfactant, which
most preferably has detergent properties. In preferred embodiments, the substrate
comprises a textile fibre and the polymeric particles may, for example, comprise particles
of polyamides, polyesters, polyalkenes, polyurethanes or their copolymers, but are most
preferably in the form of nylon chips.
The use of this cleaning method, however, presents a requirement for the cleaning chips
or beads to be efficiently separated from the cleaned substrate at the conclusion of the
cleaning operation, and this issue was initially addressed in WO-A-201 0/094959, which
provides a novel design of cleaning apparatus requiring the use of two internal drums
capable of independent rotation, and which finds application in both industrial and
domestic cleaning processes.
With a view to providing a simpler, more economical means for addressing the problem
of efficient separation of the cleaning media from the substrate at the conclusion of the
cleaning process, however, a further apparatus is disclosed in co-pending PCT Patent
Application No. PCT/GB201 0/051 960. The apparatus of PCT Patent Application No.
PCT/GB201 0/051 960, which finds application in both industrial and domestic cleaning
processes, comprises a perforated drum and a removable outer drum skin which is
adapted to prevent the ingress or egress of fluids and solid particulate matter from the
interior of the drum. The cleaning method requires attachment of the outer skin to the
drum during a first wash cycle, after which the skin is removed prior to operating a
second wash cycle, following which the cleaned substrate is removed from the drum.
The apparatus and method of PCT Patent Application No. PCT/GB201 0/051 960 is found
to be extremely effective in successfully cleaning substrates, but the requirement for the
attachment and removal of the outer skin detracts from the overall efficiency of the
process and the present inventors have, therefore, sought to address this aspect of the
cleaning operation and to provide a process wherein this procedural step is no longer
necessary. Thus, by providing for continuous circulation of the cleaning chips during the
cleaning process, it has been found possible to dispense with the requirement for the
provision of an outer skin.
Summary of the Invention
Thus, according to a first aspect of the present invention, there is provided an apparatus
for use in the cleaning of soiled substrates, said apparatus comprising:
(a) housing means, having:
(i) a first upper chamber having mounted therein a rotatably mounted
cylindrical cage, and
(ii) a second lower chamber located beneath said cylindrical cage;
(b) at least one recirculation means;
(c) access means;
(d) pumping means; and
(e) a multiplicity of delivery means,
wherein said rotatably mounted cylindrical cage comprises a drum comprising perforated
side walls, wherein up to 60% of the surface area of said side walls comprises
perforations, and said perforations comprise holes having a diameter of no greater than
25.0 mm.
In preferred embodiments of the invention, no more than 50%, more preferably no more
than 40%, of the side walls comprises perforations.
Preferably, said perforations comprise holes having a diameter of from 2 to 25 mm,
preferably from 4 to 10 mm, most preferably from 5 to 8 mm.
Said access means typically comprises a hinged door mounted in the casing, which may
be opened to allow access to the inside of the cylindrical cage, and which may be closed
in order to provide a substantially sealed system. Preferably, the door includes a
window. Optionally, said door also includes at least one addition port which facilitates
the addition of materials to said rotatably mounted cylindrical cage.
Said rotatably mounted cylindrical cage may be mounted vertically within said housing
means but, most preferably, is mounted horizontally within said housing means.
Consequently, in preferred embodiments of the invention, said access means is located
in the front of the apparatus, providing a front-loading facility. When the rotatably
mounted cylindrical cage is vertically mounted within the housing means, the access
means is located in the top of the apparatus, providing a top-loading facility. However,
for the purposes of the further description of the present invention, it will be assumed
that said rotatably mounted cylindrical cage is mounted horizontally within said housing
means.
Rotation of said rotatably mounted cylindrical cage is effected by use of drive means,
which typically comprises electrical drive means, in the form of an electric motor.
Operation of said drive means is effected by control means which may be programmed
by an operative.
Said rotatably mounted cylindrical cage is of the size which is to be found in most
commercially available washing machines and tumble driers, and may have a capacity in
the region of 10 to 7000 litres. A typical capacity for a domestic washing machine would
be in the region of 30 to 120 litres whilst, for an industrial washer-extractor, capacities
anywhere in the range of from 120 to 7000 litres are possible. A typical size in this
range is that which is suitable for a 50 kg washload, wherein the drum has a volume of
450 to 650 litres and, in such cases, said cage would generally comprise a cylinder with
a diameter in the region of 75 to 120 cm, preferably from 90 to 110 cm, and a length of
between 40 and 100 cm, preferably between 60 and 90 cm. Generally, the cage will
have 10 litres of volume per kg of washload to be cleaned.
Said apparatus is designed to operate in conjunction with soiled substrates and cleaning
media comprising a solid particulate material, which is most preferably in the form of a
multiplicity of polymeric particles. These polymeric particles are required to be efficiently
circulated to promote effective cleaning and the apparatus, therefore, preferably includes
circulation means. Thus, the inner surface of the cylindrical side walls of said rotatably
mounted cylindrical cage preferably comprises a multiplicity of spaced apart elongated
protrusions affixed essentially perpendicularly to said inner surface. Preferably, said
protrusions additionally comprise air amplifiers which are typically driven pneumatically
and are adapted so as to promote circulation of a current of air within said cage.
Typically said apparatus comprises from 3 to 10, most preferably 4, of said protrusions,
which are commonly referred to as lifters.
In operation, agitation is provided by rotation of said rotatably mounted cylindrical cage.
However, in preferred embodiments of the invention, there is also provided additional
agitating means, in order to facilitate the efficient removal of residual solid particulate
material at the conclusion of the cleaning operation. Preferably, said agitating means
comprises an air jet.
Said rotatably mounted cylindrical cage is located within a first upper chamber of said
housing means and beneath said first upper chamber is located a second lower
chamber which functions as a collection chamber for said cleaning media. Preferably,
said lower chamber comprises an enlarged sump.
Said housing means is connected to standard plumbing features, thereby providing at
least one recirculation means, in addition to a multiplicity of delivery means, by virtue of
which at least water and, optionally, cleaning agents such as surfactants may be
introduced into the apparatus. Said apparatus may additionally comprise means for
circulating air within said housing means, and for adjusting the temperature and humidity
therein. Said means may typically include, for example, a recirculating fan, an air
heater, a water atomiser and/or a steam generator. Additionally, sensing means may
also be provided for determining, inter alia, the temperature and humidity levels within
the apparatus, and for communicating this information to the control means.
Thus, said apparatus comprises at least one recirculation means, thereby facilitating
recirculation of said solid particulate material from said lower chamber to said rotatably
mounted cylindrical cage, for re-use in cleaning operations. Preferably, said first
recirculation means comprises ducting connecting said second chamber and said
rotatably mounted cylindrical cage. More preferably, said ducting comprises separating
means for separating said solid particulate material from water and control means,
adapted to control entry of said solid particulate material into said cylindrical cage.
Typically, said separating means comprises a filter material such as wire mesh located in
a receptor vessel above said cylindrical cage, and said control means comprises a valve
located in feeder means, preferably in the form of a feed tube attached to said receptor
vessel, and connected to the interior of the cylindrical cage.
Recirculation of solid particulate matter from said lower chamber to said rotatably
mounted cylindrical cage is achieved by the use of pumping means comprised in said
first recirculation means, wherein said pumping means are adapted to deliver said solid
particulate matter to said separating means and said control means, adapted to control
the re-entry of said solid particulate matter into said rotatably mounted cylindrical cage.
Preferably, said apparatus additionally includes a second recirculation means, allowing
for the return of water separated by said separating means to said lower chamber,
thereby facilitating re-use of said water in an environmentally beneficial manner.
Preferably, said lower chamber comprises additional pumping means to promote
circulation and mixing of the contents thereof, in addition to heating means, allowing the
contents to be raised to a preferred temperature of operation.
In operation, during a typical cycle, soiled garments are first placed into said rotatably
mounted cylindrical cage. Then, the solid particulate material and the necessary amount
of water, together with any required additional cleaning agent, are added to said
rotatably mounted cylindrical cage. Optionally, said materials are heated to the desired
temperature in the lower chamber comprised in the housing means and introduced, via
the first recirculation means, into the cylindrical cage. Alternatively, said cleaning agent
may, for example, be pre-mixed with water and added either via an addition port
mounted on the access means or through said separating means located above said
cylindrical cage. Optionally, this water may be heated. Additional cleaning agents, of
which bleach is a typical example, may be added with more, optionally heated, water at
later stages during the wash cycle, using the same means.
During the course of agitation by rotation of the cage, the fluids and a quantity of the
solid particulate material fall through the perforations in the cage and into the lower
chamber of the apparatus. Thereafter, the solid particulate material may be re circulated
via the first recirculation means such that it is transferred to said separating means, from
which it is returned, in a manner controlled by said control means, to the cylindrical cage
for continuation of the washing operation. This process of continuous circulation of the
solid particulate material continuous throughout the washing operation until cleaning is
completed.
Thus, the solid particulate material which falls through the perforations in the walls of
said rotatably mounted cylindrical cage and into said lower chamber is carried to the top
side of said rotatably mounted cylindrical cage, wherein it is caused, by means of gravity,
to fall through said separation means and, by operation of control means, through said
feeder means and back into said cage, thereby to continue the cleaning operation.
According to a second aspect of the present invention, there is provided a method for
cleaning a soiled substrate, said method comprising the treatment of the substrate with a
formulation comprising solid particulate cleaning material and wash water, wherein said
method is carried out in an apparatus according to the first aspect of the invention.
Preferably, said method comprises the steps of:
(a) introducing a solid particulate cleaning material and water into the second
lower chamber of an apparatus according to the first aspect of the
invention;
(b) agitating and heating said solid particulate cleaning material and water;
(c) loading at least one soiled substrate into said rotatably mounted
cylindrical cage via access means;
(d) closing the access means so as to provide a substantially sealed system;
(e) introducing said solid particulate cleaning material and water into said
rotatably mounted cylindrical cage via recirculating means;
(f) operating the apparatus for a wash cycle, wherein said rotatably mounted
cylindrical is caused to rotate and wherein fluids and solid particulate
cleaning material are caused to fall through perforations in said rotatably
mounted cylindrical cage into said second lower chamber in a controlled
manner;
(g) operating pumping means so as to transfer fresh solid particulate
cleaning material and recycle used solid particulate cleaning material to
separating means;
(h) operating control means so as to add said fresh and recycled solid
particulate cleaning material to said rotatably mounted cylindrical cage in
a controlled manner; and
(i) continuing with steps (f), (g) and (h) as required to effect cleaning of the
soiled substrate.
Preferably, additional cleaning agents are employed in said method. Said additional
cleaning agents may be added to the lower chamber of said apparatus with said solid
particulate cleaning material, optionally heated to the desired temperature therein and
introduced, via the first recirculation means, into the cylindrical cage. Preferably,
however, said additional cleaning agents are pre-mixed with water, which mixture may
optionally be heated before addition to said cylindrical cage via an addition port mounted
on the access door. Optionally, this addition may be carried out using a spray head in
order to better distribute said cleaning agents in the washload. Alternatively, said
addition of cleaning agents may be made via the separating means located above said
cage.
Preferably, pumping of said fresh and recycled solid particulate cleaning material
proceeds at a rate sufficient to maintain approximately the same level of cleaning
material in said rotatably mounted cylindrical cage throughout the cleaning operation,
and to ensure that the ratio of cleaning material to soiled substrate stays substantially
constant until the wash cycle has been completed.
The generation of suitable G forces, in combination with the action of the solid
particulate cleaning material, is a key factor in achieving an appropriate level of cleaning
of the soiled substrate. G is a function of the cage size and the speed of rotation of the
cage and, specifically, is the ratio of the centripetal force generated at the inner surface
of the cage to the static weight of the washload. Thus, for a cage of inner radius r (m),
rotating at R (rpm), with a washload of mass M (kg), and an instantaneous tangential
velocity of the cage v (m/s), and taking g as the acceleration due to gravity at 9.81 m/s2:
Centripetal force = Mv2/r
Washload static weight = Mg
v = 2TTrR /60
Hence, G = 4TT 2r2R2/3600rg = 4TT 2rR2/3600g = 1. 18 x 10 3rR2
When, as is usually the case, r is expressed in centimetres, rather than metres, then:
G = 1. 1 18 x 10 5rR2
Hence, for a drum of radius 49 cm rotating at 800 rpm, G = 350.6.
In a preferred embodiment of the invention, a cylindrical drum having a diameter of 98
cm is rotated at a speed of 30-800 rpm in order to generate G forces of 0.49-350.6 at
different stages during the cleaning process. In examples of alternative embodiments of
the invention, a 48 cm diameter drum rotating at 1600 rpm can generate 687 G, whilst a
60 cm diameter drum at the same speed of rotation generates 859 G.
In preferred embodiments of the invention, the claimed method additionally provides for
separation and recovery of the solid particulate cleaning material, and this may then be
re-used in subsequent washes.
During the wash cycle, rotation of said rotatably mounted cylindrical cage is preferably
caused to occur at rotation speeds such that G is < 1 which, for a 98 cm diameter cage,
requires a rotation speed of up to 42 rpm, with preferred rates of rotation being between
30 and 40 rpm.
On completion of the wash cycle, feeding of solid particulate cleaning material into the
rotatably mounted cylindrical cage ceases and the speed of rotation of the cage is
initially increased in order to effect a measure of drying of the cleaned substrate, thereby
generating G forces of between 10 and 1000, more specifically between 40 and 400.
Typically, for a 98 cm diameter cage, rotation is at a speed of up to 800 rpm in order to
achieve this effect. Subsequently, rotation speed is reduced and returned to the speed
of the wash cycle so as to allow for removal of the solid particulate cleaning material.
Optionally, following said bead removal operation, said method may additionally
comprise a rinsing operation, wherein additional water may be added to said rotatably
mounted cylindrical cage in order to effect complete removal of any additional cleaning
agent employed in the cleaning operation. Water may be added to said cylindrical cage
via said addition port mounted on said access door. Again, addition may optionally be
carried out by means of a spray head in order to achieve better distribution of the rinsing
water in the washload. Alternatively, said addition may be via the separating means, or
by overfilling the second, lower chamber of said apparatus with water such that it enters
the first, upper chamber and thereby partially submerges said rotatably mounted
cylindrical cage and enters into said cage. Following rotation at the same speed as
during the wash cycle, water is removed from said cage by allowing the water level to fall
as appropriate and, whatever method of rinse water addition is employed, the speed of
rotation of the cage is then increased so as to achieve a measure of drying of the
substrate. Typically, for a 98 cm diameter cage, rotation is at a speed of up to 800 rpm
in order to achieve this effect. Subsequently, rotation speed is reduced and returned to
the speed of the wash cycle, thereby allowing for final removal of any remaining solid
particulate cleaning material. Said rinsing and drying cycles may be repeated as often
as desired.
Optionally, said rinse cycle may be used for the purposes of substrate treatment,
involving the addition of treatment agents such as anti-redeposition additives, optical
brighteners, perfumes, softeners and starch to the rinse water.
Said solid particulate cleaning material is preferably subjected to a cleaning operation in
said lower chamber by sluicing said chamber with clean water in the presence or
absence of a cleaning agent, such as a surfactant. Optionally, this water may be
heated. Alternatively, cleaning of the solid particulate cleaning material may be achieved
as a separate stage in said rotatably mounted cylindrical cage, again using water which
may optionally be heated.
Generally, any remaining solid particulate cleaning material on said at least one
substrate may be easily removed by shaking the at least one substrate. If necessary,
however, further remaining solid particulate cleaning material may be removed by
suction means, preferably comprising a vacuum wand.
Brief Description of the Drawings
The invention will now be further illustrated by reference to the following drawings,
wherein:
Figures 1(a) and (b) show an apparatus according to the invention, and illustrate
aspects of the recirculation means of the apparatus.
Detailed Description of the Invention
The apparatus according to the invention may be used for the cleaning of any of a wide
range of substrates including, for example, plastics materials, leather, paper, cardboard,
metal, glass or wood. In practice, however, said apparatus is principally designed for
use in the cleaning of substrates comprising textile fibre garments, and has been shown
to be particularly successful in achieving efficient cleaning of textile fibres which may, for
example, comprise either natural fibres, such as cotton, or man-made and synthetic
textile fibres, for example nylon 6,6, polyester, cellulose acetate, or fibre blends thereof.
Most preferably, the solid particulate cleaning material comprises a multiplicity of
polymeric particles. Typically, the polymeric particles comprise polyalkenes such as
polyethylene and polypropylene, polyamides, polyesters or polyurethanes, which may be
foamed or unfoamed. Furthermore, said polymers may be linear or crosslinked.
Preferably, however, said polymeric particles comprise polyamide or polyester particles,
most particularly particles of nylon, polyethylene terephthalate or polybutylene
terephthalate, most preferably in the form of beads. Said polyamides and polyesters are
found to be particularly effective for aqueous stain/soil removal, whilst polyalkenes are
especially useful for the removal of oil-based stains.
Various nylon or polyester homo- or co-polymers may be used including, but not limited
to, Nylon 6, Nylon 6,6, polyethylene terephthalate and polybutylene terephthalate.
Preferably, the nylon comprises Nylon 6,6 homopolymer having a molecular weight in
the region of from 5000 to 30000 Daltons, preferably from 10000 to 20000 Daltons, most
preferably from 15000 to 16000 Daltons. The polyester will typically have a molecular
weight corresponding to an intrinsic viscosity measurement in the range of from 0.3-1 .5
dl/g as measured by a solution technique such as ASTM D-4603.
Optionally, copolymers of the above polymeric materials may be employed for the
purposes of the invention. Specifically, the properties of the polymeric materials may be
tailored to specific requirements by the inclusion of monomeric units which confer
particular properties on the copolymer. Thus, the copolymers may be adapted to attract
particular staining materials by including monomer units in the polymer chain which, inter
alia, are ionically charged, or include polar moieties or unsaturated organic groups.
Examples of such groups may include, for example, acid or amino groups, or salts
thereof, or pendant alkenyl groups.
The polymeric particles are of such a shape and size as to allow for good flowability and
intimate contact with the textile fibre. A variety of shapes of particles can be used, such
as cylindrical, spherical or cuboid; appropriate cross-sectional shapes can be employed
including, for example, annular ring, dog-bone and circular. Most preferably, however,
said particles comprise cylindrical or spherical beads.
The particles may have smooth or irregular surface structures and can be of solid or
hollow construction. Particles are of such a size as to have an average mass of 1-35
mg, preferably from 10-30 mg, more preferably from 12-25 mg, and with a surface area
of 10-1 20 mm2, preferably from 15-50 mm2, more preferably from 20-40 mm2.
In the case of cylindrical beads, the preferred particle diameter is in the region of from
1.0 to 6.0 mm, more preferably from 1.5 to 4.0 mm, most preferably from 2.0 to 3.0 mm,
and the length of the beads is preferably in the range from 1.0 to 4.0 mm, more
preferably from 1.5 to 3.5 mm, and is most preferably in the region of 2.0 to 3.0 mm.
Typically, for spherical beads, the preferred diameter of the sphere is in the region of
from 1.0 to 6.0 mm, more preferably from 2.0 to 4.5 mm, most preferably from 2.5 to 3.5
mm.
In order to provide additional lubrication to the cleaning system and thereby improve the
transport properties within the system, water is added to the system. Thus, more
efficient transfer of the at least one cleaning material to the substrate is facilitated, and
removal of soiling and stains from the substrate occurs more readily. Optionally, the
soiled substrate may be moistened by wetting with mains or tap water prior to loading
into the apparatus of the invention. In any event, water is added to the rotatably
mounted cylindrical cage of the apparatus according to the invention such that the
washing treatment is carried out so as to achieve a water to substrate ratio which is
preferably between 2.5:1 and 0.1 : 1 w/w; more preferably, the ratio is between 2.0:1 and
0.8:1 , with particularly favourable results having been achieved at ratios such as 1.75:1 ,
1.5:1 , 1.2:1 and 1. 1 : 1 . Most conveniently, the required amount of water is introduced
into the rotatably mounted cylindrical cage of the apparatus according to the invention
after loading of the soiled substrate into said cage. An additional amount of water will
migrate into the cage during the circulation of the solid particulate cleaning material, but
the amount of carry over is minimised by the action of the separating means.
Whilst, in one embodiment, the method of the invention envisages the cleaning of a
soiled substrate by the treatment of a moistened substrate with a formulation which
essentially consists only of a multiplicity of polymeric particles, in the absence of any
further additives, optionally in other embodiments the formulation employed may
additionally comprise at least one cleaning agent. Said at least one cleaning agent may
include at least one cleaning material. Preferably, the at least one cleaning material
comprises at least one detergent composition. Optionally, said at least one cleaning
material is mixed with said polymeric particles but, in a preferred embodiment, each of
said polymeric particles is coated with said at least one cleaning material.
The principal components of the detergent composition comprise cleaning components
and post-treatment components. Typically, the cleaning components comprise
surfactants, enzymes and bleach, whilst the post-treatment components include, for
example, anti-redeposition additives, perfumes and optical brighteners.
However, the detergent formulation may optionally include one or more other additives
such as, for example builders, chelating agents, dye transfer inhibiting agents,
dispersants, enzyme stabilizers, catalytic materials, bleach activators, polymeric
dispersing agents, clay soil removal agents, suds suppressors, dyes, structure
elasticizing agents, fabric softeners, starches, carriers, hydrotropes, processing aids
and/or pigments.
Examples of suitable surfactants may be selected from non-ionic and/or anionic and/or
cationic surfactants and/or ampholytic and/or zwitterionic and/or semi-polar nonionic
surfactants. The surfactant is typically present at a level of from about 0.1%, from about
1%, or even from about 5% by weight of the cleaning compositions to about 99.9%, to
about 80%, to about 35%, or even to about 30% by weight of the cleaning compositions.
The compositions may include one or more detergent enzymes which provide cleaning
performance and/or fabric care benefits. Examples of suitable enzymes include, but are
not limited to, hemicellulases, peroxidases, proteases, other cellulases, other xylanases,
lipases, phospholipases, esterases, cutinases, pectinases, keratanases, reductases,
oxidases, phenoloxidases, lipoxygenases, ligninases, pullulanases, tannases,
pentosanases, malanases, [beta]-glucanases, arabinosidases, hyaluronidase,
chondroitinase, laccase, and amylases, or mixtures thereof. A typical combination may
comprise a mixture of enzymes such as protease, lipase, cutinase and/or cellulase in
conjunction with amylase.
Optionally, enzyme stabilisers may also be included amongst the cleaning components.
In this regard, enzymes for use in detergents may be stabilised by various techniques,
for example by the incorporation of water-soluble sources of calcium and/or magnesium
ions in the compositions.
The compositions may include one or more bleach compounds and associated
activators. Examples of such bleach compounds include, but are not limited to,
peroxygen compounds, including hydrogen peroxide, inorganic peroxy salts, such as
perborate, percarbonate, perphosphate, persilicate, and mono persulphate salts (e.g.
sodium perborate tetrahydrate and sodium percarbonate), and organic peroxy acids
such as peracetic acid, monoperoxyphthalic acid, diperoxydodecanedioic acid, N,N'-
terephthaloyl-di(6-aminoperoxycaproic acid), N,N'-phthaloylaminoperoxycaproic acid and
amidoperoxyacid. Bleach activators include, but are not limited to, carboxylic acid esters
such as tetraacetylethylenediamine and sodium nonanoyloxybenzene sulphonate.
Suitable builders may be included in the formulations and these include, but are not
limited to, the alkali metal, ammonium and alkanolammonium salts of polyphosphates,
alkali metal silicates, alkaline earth and alkali metal carbonates, aluminosilicates,
polycarboxylate compounds, ether hydroxypolycarboxylates, copolymers of maleic
anhydride with ethylene or vinyl methyl ether, 1,3,5-trihydroxybenzene-2,4,6-trisulphonic
acid, and carboxymethyl-oxysuccinic acid, various alkali metal, ammonium and
substituted ammonium salts of polyacetic acids such as ethylenediamine tetraacetic acid
and nitrilotriacetic acid, as well as polycarboxylates such as mellitic acid, succinic acid,
oxydisuccinic acid, polymaleic acid, benzene 1,3,5-tricarboxylic acid,
carboxymethyloxysuccinic acid, and soluble salts thereof.
The compositions may also optionally contain one or more copper, iron and/or
manganese chelating agents and/or one or more dye transfer inhibiting agents.
Suitable polymeric dye transfer inhibiting agents include, but are not limited to,
polyvinylpyrrolidone polymers, polyamine N-oxide polymers, copolymers of Nvinylpyrrolidone
and N-vinylimidazole, polyvinyloxazolidones and polyvinylimidazoles or
mixtures thereof.
Optionally, the detergent formulations can also contain dispersants. Suitable watersoluble
organic materials are the homo- or co-polymeric acids or their salts, in which the
polycarboxylic acid may comprise at least two carboxyl radicals separated from each
other by not more than two carbon atoms.
Said anti-redeposition additives are physico-chemical in their action and include, for
example, materials such as polyethylene glycol, polyacrylates and carboxy methyl
cellulose.
Optionally, the compositions may also contain perfumes Suitable perfumes are
generally multi-component organic chemical formulations which can contain alcohols,
ketones, aldehydes, esters, ethers and nitrile alkenes, and mixtures thereof.
Commercially available compounds offering sufficient substantivity to provide residual
fragrance include Galaxolide ( 1 ,3,4,6,7, 8-hexahydro-4,6, 6,7, 8,8-
hexamethylcyclopenta(g)-2-benzopyran), Lyral (3- and 4-(4-hydroxy-4-methyl-pentyl)
cyclohexene-1 -carboxaldehyde and Ambroxan ((3aR,5aS,9aS,9bR)-3a,6,6,9atetramethyl-
2,4,5,5a,7,8,9,9b-octahydro-1 H-benzo[e][1] benzofuran). One example of a
commercially available fully formulated perfume is Amour Japonais supplied by Symrise®
AG.
Suitable optical brighteners fall into several organic chemical classes, of which the most
popular are stilbene derivatives, whilst other suitable classes include benzoxazoles,
benzimidazoles, 1,3-diphenyl-2-pyrazolines, coumarins, 1,3,5-triazin-2-yls and
naphthalimides. Examples of such compounds include, but are not limited to, 4,4'-bis[[6-
anilino-4(methylamino)-1 ,3,5-triazin-2-yl]amino]stilbene-2,2'-disulphonic acid, 4,4'-bis[[6-
anilino-4-[(2-hydroxyethyl)methylamino]-1 ,3,5-triazin-2-yl]amino]stilbene-2,2'- disulphonic
acid, disodium salt, 4,4'-Bis[[2-anilino-4-[bis(2-hydroxyethyl)amino]-1 ,3,5-triazin-6-
yl]amino]stilbene-2,2'-disulphonic acid, disodium salt, 4,4'-bis[(4,6-dianilino-1 ,3,5-triazin-
2-yl)amino]stilbene-2, 2 -disulphonic acid, disodium salt, 7-diethylamino-4-
methylcoumarin, 4,4'-Bis[(2-anilino-4-morpholino-1 ,3,5-triazin-6-yl)amino]-2,2'-
stilbenedisulphonic acid, disodium salt, and 2,5-bis(benzoxazol-2-yl)thiophene.
Said agents may be used either alone or in any desired combination and may be added
to the cleaning system at appropriate stages during the cleaning cycle in order to
maximise their effects.
In any event, however, when the method of the invention is performed in the presence of
at least one additional cleaning agent, the quantity of said cleaning agent required in
order to achieve satisfactory cleaning performance is significantly reduced from the
quantities required with the methods of the prior art. This, in turn, has beneficial effects
in terms of the reduced quantity of rinse water that is subsequently required to be used.
The ratio of solid particulate cleaning material to substrate is generally in the range of
from 0.1 : 1 to 10:1 w/w, preferably in the region of from 0.5:1 to 5:1 w/w, with particularly
favourable results being achieved with a ratio of between 1: 1 and 3:1 w/w, and
especially at around 2:1 w/w. Thus, for example, for the cleaning of 5 g of fabric, 10 g of
polymeric particles, optionally coated with surfactant, would be employed in one
embodiment of the invention. The ratio of solid particulate cleaning material to substrate
is maintained at a substantially constant level throughout the wash cycle.
The apparatus and the method of the present invention may be used for either small or
large scale batchwise processes and find application in both domestic and industrial
cleaning processes.
As previously noted, the method of the invention finds particular application in the
cleaning of textile fibres. The conditions employed in such a cleaning system do,
however, allow the use of significantly reduced temperatures from those which typically
apply to the conventional wet cleaning of textile fabrics and, as a consequence, offer
significant environmental and economic benefits. Thus, typical procedures and
conditions for the wash cycle require that fabrics are generally treated according to the
method of the invention at, for example, temperatures of between 5 and 95 ° for a
duration of between 5 and 120 minutes in a substantially sealed system. Thereafter,
additional time is required for the completion of the rinsing and bead separation stages
of the overall process, so that the total duration of the entire cycle is typically in the
region of 1 hour. The preferred operating temperatures for the method of the invention
are in the range of from 10 to 60°C and, more preferably, from 15 to 40°C.
The cycle for removal of solid particulate material may optionally be performed at room
temperature and it has been established that optimum results are achieved at cycle
times of between 2 and 30 minutes, preferably between 5 and 20 minutes.
The results obtained are very much in line with those observed when carrying out
conventional wet (or dry) cleaning procedures with textile fabrics. The extent of cleaning
and stain removal achieved with fabrics treated by the method of the invention is seen to
be very good, with particularly outstanding results being achieved in respect of
hydrophobic stains and aqueous stains and soiling, which are often difficult to remove.
The energy requirement, the total volume of water used, and the detergent consumption
of the method of the invention are all significantly lower than those levels associated with
the use of conventional aqueous washing procedures, again offering significant
advantages in terms of cost and environmental benefits.
Additionally, it has been demonstrated that re-utilisation of the polymer particles is
possible, allowing for the performance of multiple washes with the same solid particulate
cleaning material. Re-use of the particles in this way for repeat cleaning procedures
provides significant economic benefits and the achievement of satisfactory results after
multiple washes is assisted by the nature of the process, which relies on continuous
cleaning of the particulate cleaning material as an integral part of the procedure,
although it generally found that some deterioration in performance is eventually
observed.
In a typical example of an operating cycle according to the method of the invention, an
initial addition of solid particulate cleaning material (approximately 43 kg) is added to a
washload of soiled substrate ( 15 kg) in the rotatably mounted cylindrical cage of 98 cm
diameter, after which rotation of the cage commences at around 40 rpm. Thereafter,
further solid particulate cleaning material (10 kg) is pumped into said rotatably mounted
cylindrical cage via the separating means and control means approximately every 30
seconds throughout the duration of the wash cycle which may typically continue for
around 30 minutes. The system is thereby designed to pump and add solid particulate
cleaning material at a sufficient rate to maintain roughly the same level of solid
particulate cleaning material in the rotatably mounted cylindrical cage (approximately
2.9:1 by weight, for 43 kg of beads and 15 kg of cloth) throughout the wash.
Thus, during the wash cycle, the solid particulate cleaning material is continually falling
out of the rotatably mounted cylindrical cage through its perforations, and is being
recycled and added, together with fresh cleaning material, via the separating means and
control means. This process may either be controlled manually, or operated
automatically. The rate of exit of the solid particulate cleaning material from the
rotatably mounted cylindrical cage is essentially controlled by means of its specific
design. The key parameters in this regard include the size of the perforations, the
number of perforations and the pattern of the perforations.
Generally, the perforations are sized at around 2-3 times the average particle diameter
of the solid particulate cleaning material which, in a typical example, results in
perforations having a diameter of no greater than 10.0 mm.
In a preferred embodiment of the invention, a rotatably mounted cylindrical cage
(diameter 98 cm, depth 65 cm) would be drilled to have stripes of 8.0 mm diameter
perforations running from front to back in approximately 9 cm wide strips alternating with
solid sections, so that only around 34% of the surface area of the cylindrical walls of the
cage comprises perforations. The perforations are preferably banded in stripes on the
cylindrical walls of the rotatably mounted cylindrical cage or, alternatively, uniformly
distributed over the cage wall, rather than being exclusively located, for example, in one
half of the cage.
The rate of exit of the solid particulate cleaning material from the rotatably mounted
cylindrical cage is also affected by the speed of rotation of said cage, with higher rotation
speeds increasing the centripetal force so as to increase the tendency to push the solid
particulate cleaning material out of the perforations. However, higher cage rpm values
also compress the substrate being cleaned, so as to trap the cleaning material within
folds thereof. The most suitable rotation speeds are, therefore, generally found to be
between 30 and 40 rpm at 98 cm cage diameter, or those which generate G values of
between 0.49 and 0.88. The maximum rotation speed in order to avoid bead trapping in
garments is found to be around 42 rpm (G = 0.97).
In addition, the moisture level in the wash also has an effect, with wetter substrates
tending to retain cleaning material for a longer time than drier substrates. Consequently,
overwetting of substrate can, if necessary, be employed in order to further control the
rate of exit of solid particulate cleaning material.
On completion of the wash cycle, addition of solid particulate cleaning material to the
rotatably mounted cylindrical cage is ceased, and the cage is rotated for a short time
(about 2 minutes) at low rpm (30-40 rpm; G = 0.49-0.88) to allow the bulk of the solid
particulate cleaning material to leave the cage. The cage is then rotated at high speed
(between 300 and 800 rpm; G = 49.3-350.6) for about 2 minutes in order to extract some
liquid and dry the substrate to an extent. The rotation speed is then returned to the
same low rpm as in the wash cycle in order to complete the removal of cleaning
material; this generally takes around 20 minutes.
The method of the invention has been shown to be particularly successful in the removal
of cleaning material from the cleaned substrate after washing, and tests with cylindrical
polyester beads, and nylon beads comprising Nylon 6,6 polymer, have indicated bead
removal efficacy such that on average <20 beads per garment remain in the washload at
the end of the bead separation cycle. Generally, this can be further reduced to an
average of <10 beads per garment and, in optimised cases wherein a 20 minute
separation cycle is employed, an average of <5 beads per garment is typically achieved.
Following said bead removal operation a series of rinses is carried out, wherein
additional water is sprayed into the rotatably mounted cylindrical cage in order to effect
complete removal of any additional cleaning agent employed in the cleaning operation.
In this embodiment of the invention, a spray head is used, which is mounted in an
addition port on the access door. The use of said spray head has been shown to better
distribute the rinsing water in the washload. By this means the overall water
consumption during the rinsing operation can also be minimised (3:1 rinse water:cloth,
typically, per rinse). The cage is rotated at low speeds again during rinse water addition
(30-40 rpm, G = 0.49-0.88 for 98 cm diameter cage), but after this operation has ceased
the cage speed is once again increased to achieve a measure of drying of the substrate
(300-800 rpm, G = 49.3-350.6). Subsequently, rotation speed is reduced and returned
to the speed of the wash cycle so as to allow for final removal of any remaining solid
particulate cleaning material. Said rinsing and drying cycles may be repeated as often
as desired (3 times is typical).
Referring to the figures provided herewith, there is seen in Figures 1(a) and (b) an
apparatus according to the invention comprising housing means ( 1 ) having a first upper
chamber having mounted therein a rotatably mounted cylindrical cage in the form of
drum (2) (perforations not shown) and a second lower chamber comprising sump (3)
located beneath said cylindrical cage. The apparatus additionally comprises, as first
recirculation means, bead and water riser pipe (4) which feeds into a bead separation
vessel (5), including filter material, typically in the form of a wire mesh, and a bead
release gate valve which feeds into bead delivery tube (6) mounted in cage entry (7).
The first recirculation means is driven by bead pump (8). Additional recirculation means
comprises return water pipe (9), which allows water to return from the bead separation
vessel (5) to the sump (3) under the influence of gravity. The apparatus also comprises
access means shown as loading door (10), though which material for cleaning may be
loaded into drum (2).
Thus, Figure 1(a) illustrates a section of the first recirculation system, wherein the solid
particulate cleaning material in the form of beads passes from the bead separation
vessel (5) through the bead delivery tube (6) and into the drum (2), and Figure 1(b)
shows other sections of the first recirculation system, wherein the solid particulate
cleaning material comprising beads and water is driven by bead pump (8) from the
heated sump (3) through the bead and water riser pipe (4) to the bead separation vessel
(5), from which separated water returns to the sump via return water pipe (9) under the
influence of gravity. The main motor (20) of the apparatus, responsible for driving the
drum (2), is also depicted.
In operation, the sump (3), together with its contents (water and polymer beads) may be
heated by heater pads attached to the outer surface of the sump (3). The bead pump
(8) pumps the beads and water up through the riser pipe (4) to the bead separation
vessel (5) where the beads are retained within the vessel (5) whilst the drained water
returns to the sump via a return pipe (9). The rigid filter material within the separation
vessel allows the water carried with the beads to escape from within the mass of the
beads, whilst the gate valve retains the beads within the vessel (5). Further beads may
then be pumped into the separation vessel (5). The water drains from the vessel (5) and
returns to the sump (3). When the valve in vessel (5) is opened, the beads pass through
the valve and travel down the bead delivery tube (6), through the cage entry (7) and in to
the drum (2). Cold water may be added to the contents of the drum (2) via a cold water
feed port located in cage entry (7). The wash load is placed into the drum (2) through
openable loading door ( 1 0), and detergent is added to the system via a port in the sump
(3). The system temperature is monitored via a temperature probe, preferably mounted
in bead delivery tube (6), whilst a water pump circulates water around the sump (3).
Hence, the system provides a means of adding polymer beads to a wash load,
performing the washing cycle, and then separating the beads from the wash load once
the washing cycle is complete. The washing process may be conveniently illustrated by
describing one complete wash cycle.
Thus, polymer beads together with the required addition of water to achieve efficient
pumping are optionally heated to operating temperature in the sump (3) by the sump
heater pads, and the water is recirculated through the beads using the water pump to
ensure that a uniform bulk temperature is achieved. Once the required operating
temperature is achieved, the wash load is placed into the drum (2) and the loading door
( 10) is closed. Initially, cold water is added to the wash load via the cold water feed port
to ensure that any stains (such as egg) are not 'baked' on to the fabric when the warm
wash water and beads are introduced. Cleaning materials such as detergents may be
added to the polymer beads in the sump, but are preferably added at this stage, with
water; said addition may be made either via an addition port (not shown) mounted on the
door ( 10) or through the bead separation vessel (5) and bead delivery tube (6). The
wash load is agitated gently to disperse the cold water evenly amongst the load and fully
wet out the cloth. Additional cleaning materials, of which bleach is a typical example,
may be added with more, optionally heated, water at later stages during the wash cycle
via the same means of addition.
Once the initial working temperature has been reached by the beads and water within
the sump, the bead pump (8) pumps a mixture of beads and water up to the bead
separation vessel (5). Excess water is allowed to drain back to the sump (3) and the
valve is then opened to release the beads into the drum (2) via the bead delivery tube
(6). This operation is repeated a number of times until the required quantity of beads
has been delivered to the drum (2).
The system then performs a wash cycle in a similar manner to a standard washing
machine with the cage rotating at between 30 and 40 rpm (G = 0.49-0.88 for a 98 cm
cylindrical cage) for several revolutions in one direction, then rotating a similar number of
rotations in the opposite direction. This sequence is repeated for up to 60 minutes.
During this time, the beads are continually falling though the cage perforations into the
sump (3) and being pumped back by the bead pump (8) to the bead separation vessel
(5) from which, together with fresh beads as necessary, they are re-introduced into the
drum (2).
On completion of the wash cycle, introduction of beads into drum (2) ceases whilst the
beads remain free to fall through the cage perforations and out into the sump (3).
Following a short high speed rotation to remove some liquor from the drum and partially
dry out the cleaned substrate, a series of slow speed rotations and counter rotations is
performed to encourage the beads to fall through the perforations in the drum (2) and
return to the sump (3). This process is continued until virtually all of the beads have
been removed from within the drum (2). At any point during this bead separation
sequence, air can be blown into the drum to disrupt and cause the billowing of the cloth
to aid bead removal. The wash load can then be removed from the drum (2) via the
loading door ( 1 0).
In a preferred bead removal sequence, the drum (2) is initially rotated for 2 minutes at
between 300 and 800 rpm (G = 49.3-350.6 for a 98 cm diameter drum), then for 20
minutes at between 30 and 40 rpm, during which time the direction of rotation is
reversed approximately every 30 seconds in order to re-orientate the substrate and allow
the beads to fall from the substrate, thereby effecting efficient bead removal.
In a separate optional step, the wash load may be rinsed with water following the wash
cycle. In further optional stages, following their removal from the drum and transfer to
the sump, the beads may be cleaned by sluicing the sump with clean water in the
presence or absence of a cleaning agent, such as a surfactant. Alternatively, cleaning
of the beads may be carried out by washing them alone in the drum following removal of
the wash load.
The invention will now be further illustrated, though without in any way limiting the scope
thereof, by reference to the following examples and associated illustrations.
Examples
Example 1
Woven cotton fabric ( 194 gm 2, Whaleys, Bradford, U.K.) was stained with coffee,
lipstick, ball point pen, tomato ketchup, boot polish, grass, vacuum dirt, curry sauce and
red wine following the methods described below:
(i) Coffee
10 g of Morrisons® Full Roast coffee powder was dissolved in 50 ml distilled water at
70 °C. A 1 cm3 aliquot of the ensuing solution was applied to the fabric using a synthetic
sponge, within the confines of a 5 cm diameter circular plastic template; the stained
fabric was then allowed to dry at ambient temperature (23 °C), after which the fabric was
aged prior to use, by storage in the dark for 4 days.
(ii) Lipstick
Revlon® Super Lustrous lipstick (copper frost shade) was applied to the fabric using a
synthetic sponge to provide a uniform coverage within the confines of a 5 cm diameter
circular plastic template. The fabric was then aged following the procedure recounted
for coffee.
(iii) Ball Point Pen
A black Paper Mate® Flex Grip Ultra ball point pen was used to uniformly cover the fabric
within the confines of a 5 cm diameter circular plastic template. The fabric was then
aged following the procedure recounted for coffee.
(iv) Tomato Ketchup
Heinz® tomato ketchup was applied to the fabric using a synthetic sponge to provide a
uniform coverage within the confines of a 5 cm diameter circular plastic template. The
fabric was then aged following the procedure recounted for coffee.
(v) Boot Polish
Kiwi® black boot polish was applied to the fabric using a synthetic sponge to provide a
uniform coverage within the confines of a 5 cm diameter circular plastic template. The
fabric was then aged following the procedure recounted for coffee.
(vi) Grass
Grass was collected manually from an MG7 (National Vegetation Classification) source.
10 g of the grass was chopped with scissors and blended with 200 ml of tap water using
an electronic blender. The mixture was then filtered using a metal sieve, and the filtrate
used as the staining medium. This was applied to the fabric using a synthetic sponge to
provide a uniform coverage within the confines of a 5 cm diameter circular plastic
template. The fabric was then aged following the procedure recounted for coffee.
(vii) Vacuum Dirt
Vacuum dirt was collected manually from a general domestic vacuum bag. 25 g of
vacuum dirt was mixed with 100 ml of tap water, and the mixture used to stain the fabric.
This was applied to the fabric using a synthetic sponge to provide a uniform coverage
within the confines of a 5 cm diameter circular plastic template. The fabric was then
aged following the procedure recounted for coffee.
(viii) Curry Sauce
Morrisons® own brand curry sauce was applied directly to the fabric using a synthetic
sponge to provide a uniform coverage within the confines of a 5 cm diameter circular
plastic template. The fabric was then aged following the procedure recounted for coffee.
(ix) Red Wine
"Spanish Red Wine" purchased at Morrisons® was applied directly to the fabric using a
synthetic sponge to provide a uniform coverage within the confines of a 5 cm diameter
circular plastic template. The fabric was then aged following the procedure recounted
for coffee.
Each of the stains (i)-(ix) was applied to a single (36 cm x 30 cm) piece of cotton fabric
in the pattern shown in Figure 2, in order to make up a standard stain set.
Cleaning trials were then carried out using a set of trial and control conditions, as set out
in Table 1. The trials involved the use of a preferred apparatus as hereinbefore defined
according to the method of the invention ("Xeros - Gen 1" XP1), whilst control cleaning
trials were carried out using a standard domestic washing machine (BEKO® WM51 20W,
XP2 and XP3) . In both cases (XP1 , XP2 and XP3) the standard stain sets were added
at 1/kg of washload, and a simulated sebum grease stain of 10 g/kg of washload was
also incorporated as impregnated cotton cloth (WFK SBL2004). This cloth is used to
better simulate the domestic washing environment where such collar and cuff grease is
the dominant stain (making up some 80% of the overall stain loading) . Sebum is derived
from the skin's sebaceous glands. The XP1 process was undertaken at ambient
temperature (measured as \ 5 ° ) with a 24 kg cotton and polyester/cotton mixed fabric
washload, 28.8 litres of wash water (i.e. 1.2 litres/kg washload) and 65 kg of INVISTA™
110 1 polyester beads (i.e. 2.7 kg/kg washload). A rinse cycle of four 18 litre rinses was
employed (spin speed 300 rpm in a 98 cm diameter drum ; G = 49.3) . The total water
consumption (including wash and rinse) was, therefore, only 100.8 litres, or 4.2 litres/kg
washload. The detergent used was Unilever Persil Small & Mighty® biological liquid at
3.7 g/kg of washload. The total cycle time was 95 minutes.
The domestic controls (XP2 and XP3) were carried out with a 4 kg washload, even
though the BEKO® WM51 20W is rated as a 5 kg machine. This is the widely accepted
average washload size for the European domestic market and it, in turn , makes this
control more rigorous. The increased ullage in the drum results in more mechanical
action and a better wash performance. It should also be noted that whilst XP2 was run
at ambient wash temperature (measured as 15°C), XP3 was run at a higher wash
temperature (40 € ) . In addition , both the XP2 and XP3 were run with a 9.3 g/kg
washload of detergent, which was considerably more than for XP1, and the water
consumption was also higher (wash plus rinse 56 kg , or 14.0 litres/kg of washload).
Finally, the total process cycle time for XP2 and XP3 was 127 minutes, which is
considerably longer than for XP1 , using the process according to the invention. These
parameters were a function of the cycle chosen on the BEKO® machine (40 , cotton),
and they also obviously increased the rigour of the control. It should be noted that the
BEKO® WM51 20W does not have an ambient cycle in its standard programme choices;
hence, the ambient cycle was achieved in this instance by disconnecting the heater from
the machine and re-running the 40^ cotton cycle, so that XP3 had the same cycle time
as XP2.
The test parameters are summarised in Table 1.
5
Table 1 XP1 , XP2 & XP3 Wash Test Details
The level of cleaning achieved was assessed using colour measurement. Reflectance
10 values of samples were measured using a Datacolor Spectraflash SF600
spectrophotometer interfaced to a personal computer, employing a 10° standard
observer, under illuminant D65, with the UV component included and specular component
excluded; a 3 cm viewing aperture was used. Measurements using a single thickness of
fabric were made. The CIE L* colour co-ordinate was taken for each stain and then the
15 average values were recorded as 'Enzyme' (grass and tomato ketchup stain average),
'Oxidise' (coffee, red wine and ball point pen average), and 'Particulate' (vacuum dirt,
boot polish and lipstick stain average), with the curry sauce stain being measured
individually. The sebum stain removal and level of redeposition on the cloth (i.e. the
background whiteness on each stain set) were also measured individually.
20
These results are set out in Figures 3 to 6, with higher values indicating better cleaning
performance, or redeposition control. Comparison of XP1 with XP2 shows the cleaning
carried out in the apparatus of the invention gave superior results for each stain class
(Figure 3), and when averaged over all stains (Figure 4) - even with the reduced
25 detergent and water levels used in XP1 versus XP2, and despite the longer cycle time of
XP2. Sebum removal was significantly better with the method of the invention (Figure
5), whilst redeposition was similar (Figure 6).
Comparison of XP1 and XP3 shows the cleaning carried out in the apparatus of the
invention gave comparable performance for each stain class (Figure 3 - slightly better
with particulate), and when averaged over all stains (Figure 4) - now even despite the
reduced detergent and water levels and significantly lower wash temperature used in
XP1 versus XP3, and the longer cycle time of XP3. Sebum removal and redeposition
were both similar (Figures 5 and 6 respectively).
Throughout the description and claims of this specification, the words "comprise" and
"contain" and variations of them mean "including but not limited to", and they are not
intended to (and do not) exclude other moieties, additives, components, integers or
steps. Throughout the description and claims of this specification, the singular
encompasses the plural unless the context otherwise requires. In particular, where the
indefinite article is used, the specification is to be understood as contemplating plurality
as well as singularity, unless the context requires otherwise.
Features, integers, characteristics, compounds, chemical moieties or groups described
in conjunction with a particular aspect, embodiment or example of the invention are to be
understood to be applicable to any other aspect, embodiment or example described
herein unless incompatible therewith. All of the features disclosed in this specification
(including any accompanying claims, abstract and drawings), and/or all of the steps of
any method or process so disclosed, may be combined in any combination, except
combinations where at least some of such features and/or steps are mutually exclusive.
The invention is not restricted to the details of any foregoing embodiments. The
invention extends to any novel one, or any novel combination, of the features disclosed
in this specification (including any accompanying claims, abstract and drawings), or to
any novel one, or any novel combination, of the steps of any method or process so
disclosed.
The reader's attention is directed to all papers and documents which are filed
concurrently with or previous to this specification in connection with this application and
which are open to public inspection with this specification, and the contents of all such
papers and documents are incorporated herein by reference.
CLAIMS
1. An apparatus for use in the cleaning of soiled substrates, said apparatus
comprising:
(a) housing means, having:
(i) a first upper chamber having mounted therein a rotatably mounted
cylindrical cage, and
(ii) a second lower chamber located beneath said cylindrical cage;
(b) at least one recirculation means;
(c) access means;
(d) pumping means; and
(e) a multiplicity of delivery means,
wherein said rotatably mounted cylindrical cage comprises a drum comprising perforated
side walls, wherein up to 60% of the surface area of said side walls comprises
perforations, and said perforations comprise holes having a diameter of no greater than
25.0 mm.
2. An apparatus as claimed in claim 1 wherein said access means may be closed
so as to provide a substantially sealed system.
3. An apparatus as claimed in claim 1 or 2 wherein said access means comprises a
hinged door mounted in the casing.
4. An apparatus as claimed in claim 1, 2 or 3 wherein said rotatably mounted
cylindrical cage is mounted horizontally within said casing.
5. An apparatus as claimed in any one of claims 1 to 4 wherein no more than 50%,
of the side walls of said rotatably mounted cylindrical cage comprises perforations.
6. An apparatus as claimed in any preceding claim wherein said perforations have a
diameter of from 2 to 25 mm.
7. An apparatus as claimed in any one of claims 1 to 6 wherein said rotatably
mounted cylindrical cage has a capacity in the region of 10 to 7000 litres.
8. An apparatus as claimed in any preceding claim wherein said cage comprises a
cylinder with a diameter in the region of 75 to 120 cm.
9. An apparatus as claimed in any preceding claim wherein said cage has a length
of between 40 and 100 cm.
10. An apparatus as claimed in any preceding claim wherein rotation of said rotatably
mounted cylindrical cage is effected by use of drive means.
11. An apparatus as claimed in claim 10 wherein said drive means comprises
electrical drive means and said electrical drive means optionally comprises an electric
motor.
12. An apparatus as claimed in claim 10 or 11 wherein operation of said drive means
is effected by control means.
13. An apparatus as claimed in any preceding claim which comprises circulation
means.
14. An apparatus as claimed in claim 13 wherein the inner surface of the cylindrical
side walls of said rotatably mounted cylindrical cage comprises circulation means
comprising a multiplicity of spaced apart elongated protrusions affixed essentially
perpendicularly to said inner surface.
15. An apparatus as claimed in claim 14 wherein said protrusions additionally
comprise air amplifiers.
16. An apparatus as claimed in claim 15 wherein said air amplifiers are driven
pneumatically and are adapted so as to promote circulation of a current of air within said
cage.
17. An apparatus as claimed in claim 15 or 16 which comprises from 3 to 10 of said
protrusions.
18. An apparatus as claimed in any preceding claim which comprises additional
agitating means, and wherein said additional agitating means optionally comprises an air
jet.
19. An apparatus as claimed in any preceding claim wherein said second lower
chamber functions as a collection chamber for cleaning media and comprises an
enlarged sump.
20. An apparatus as claimed in any preceding claim wherein said at least one
recirculation means facilitates recirculation of said solid particulate material from said
lower chamber to said rotatably mounted cylindrical cage, for re-use in cleaning
operations and comprises ducting connecting said second chamber and said rotatably
mounted cylindrical cage.
2 1 . An apparatus as claimed in claim 20 wherein said ducting comprises separating
means for separating said solid particulate material from water.
22. An apparatus as claimed in claim 2 1 wherein said separating means comprises a
vessel located above said cylindrical cage
23. An apparatus as claimed in claim 22 wherein said vessel comprises a filter
material, and said filter material optionally comprises a wire mesh.
24. An apparatus as claimed in any one of claims 20 to 23 wherein said ducting
comprises control means, adapted to control entry of said solid particulate material into
said cylindrical cage.
25. An apparatus as claimed in claim 24 wherein said control means comprises a
valve located in feeder means connected to the interior of the cylindrical cage, and
wherein said feeder means optionally comprises a feed tube.
26. An apparatus as claimed in any preceding claim wherein said first recirculation
means comprises pumping means.
27. An apparatus as claimed in any preceding claim which includes a second
recirculation means.
28. An apparatus as claimed in claim 27 wherein said second recirculation means
allows for the return of water separated by said separating means to said lower
chamber.
29. An apparatus as claimed in any preceding claim wherein said lower chamber
comprises additional pumping means to promote circulation and mixing of the contents
thereof.
30. A method for cleaning a soiled substrate, said method comprising the treatment
of the substrate with a formulation comprising solid particulate cleaning material and
wash water, wherein said method is carried out in an apparatus according to any one of
claims 1 to 29.
A method for cleaning a soiled substrate, said method comprising the steps of
introducing a solid particulate cleaning material and water into the second
lower chamber of an apparatus as claimed in any one of claims 1 to 29;
agitating and heating said solid particulate cleaning material and water;
loading at least one soiled substrate into said rotatably mounted
cylindrical cage via access means;
closing the access means so as to provide a substantially sealed system;
introducing said solid particulate cleaning material and water into said
rotatably mounted cylindrical cage via recirculating means;
operating the apparatus for a wash cycle, wherein said rotatably mounted
cylindrical is caused to rotate and wherein fluids and solid particulate
cleaning material are caused to fall through perforations in said rotatably
mounted cylindrical cage into said second lower chamber in a controlled
manner;
operating pumping means so as to transfer fresh solid particulate
cleaning material and recycle used solid particulate cleaning material to
separating means;
operating control means so as to add said fresh and recycled solid
particulate cleaning material to said rotatably mounted cylindrical cage in
a controlled manner; and
continuing with steps (f), (g) and (h) as required to effect cleaning of the
soiled substrate.
32. A method as claimed in claim 30 or 3 1 which additionally comprises a rinsing
operation wherein additional water is added to said rotatably mounted cylindrical cage.
33. A method as claimed in claim 32 wherein the rotation speed of said rotatably
mounted cylindrical cage is increased during said rinsing operation.
34. A method as claimed in claim 32 or 33 wherein substrate treatment agents are
added to the rinse water during said rinsing operation.
35. A method as claimed in claim 34 wherein said substrate treatment agents are
selected from anti-redeposition additives, optical brighteners, perfumes, softeners and
starch.
36. A method as claimed in any one of claims 30 to 35 wherein at least one
additional cleaning agent is added to said apparatus.
37. A method as claimed in claim 36 wherein said at least one additional cleaning
agent is added to the lower chamber of said apparatus with said solid particulate
cleaning material, heated to the desired temperature therein, and the introduced, via
said first recirculation means, into said cylindrical cage.
38. A method as claimed in claim 36 wherein said at least one additional cleaning
agent is pre-mixed with water and added to said cylindrical cage via an addition port
mounted on said access means.
39. A method as claimed in claim 36, 37 or 38 wherein said at least one additional
cleaning agent comprises at least one detergent composition.
40. A method as claimed in claim 39 wherein said at least one detergent
composition comprises cleaning components and post-treatment components.
4 1. A method as claimed in claim 40 wherein said cleaning components comprise
surfactants, enzymes and bleach.
42. A method as claimed in claim 40 or 4 1 wherein said post-treatment components
comprise anti-redeposition additives, perfumes and optical brighteners.
43. A method as claimed in any one of claims 39 to 42 which additionally comprises
at least one other additive selected from builders, chelating agents, dye transfer
inhibiting agents, dispersants, enzyme stabilizers, catalytic materials, bleach activators,
polymeric dispersing agents, clay soil removal agents, suds suppressors, dyes, structure
elasticizing agents, fabric softeners, starches, carriers, hydrotropes, processing aids and
pigments.
44. A method as claimed in any one of claims 30 to 43 wherein, during the wash
cycle, rotation of said rotatably mounted cylindrical cage is caused to occur at a G force
of less than 1.
45. A method as claimed in any one of claims 30 to 44 wherein, on completion of the
wash cycle, feeding of solid particulate cleaning material into said rotatably mounted
cylindrical cage ceases and the G force on the cage is increased in order to effect a
measure of drying of the cleaned substrate.
46. A method as claimed in claim 45 wherein said G force is between 10 and 1000.
47. A method as claimed in claim 45 or 46 wherein G force is subsequently reduced
to below 1 so as to allow for removal of the solid particulate cleaning material.
48. A method as claimed in any one of claims 30 to 47 wherein said solid particulate
cleaning material is subjected to a cleaning operation in said lower chamber by sluicing
said chamber with clean water.
49. A method as claimed in any one of claims 37 to 47 wherein said solid particulate
cleaning material is subjected to a cleaning operation in said rotatably mounted
cylindrical cage.
50. A method as claimed in claim 48 or 49 wherein said cleaning operation is carried
out in the presence of a cleaning agent.
5 1 . A method as claimed in any one of claims 30 to 50 wherein said at least one
soiled substrate comprises at least one textile fibre garment.
52. A method as claimed in any one of claims 30 to 5 1 wherein said solid particulate
cleaning material comprises a multiplicity of polymeric particles and said polymeric
particles optionally comprise particles of polyamides, polyesters, polyalkenes or
polyurethanes or their copolymers.
53. A method as claimed in claim 52 wherein said polyamide particles comprise
nylon beads.
54. A method as claimed in claim 52 wherein said polyester particles comprise
polyethylene terephthalate or polybutylene terephthalate beads.
55. A method as claimed in claim 52 wherein said polyalkene particles comprise
polyethylene or polypropylene beads.
56. A method as claimed in claim 52 wherein said polyurethane particles comprise
beads of foamed or unfoamed polyurethane.
57. A method as claimed in any one of claims 52 to 56 wherein said polymeric
particles comprise crosslinked or uncrosslinked polymers.
58. A method as claimed in any one of claims 30 to 57 wherein said washing
treatment is carried out so as to achieve a water to substrate ratio of between 2.5:1 to
0.1 : 1 w/w.
59. A method as claimed in any one of claims 30 to 58 wherein the ratio of solid
particulate cleaning material to substrate is in the range of from 0.1 : 1 to 10:1 w/w.
60. A method as claimed in any one of claims 30 to 59 wherein the wash cycle is
performed at temperatures of between 5 and 95 °C.
6 1 . A method as claimed in any one of claims 30 to 60 wherein the wash cycle is
performed for a duration of between 5 and 120 minutes.
62. A method as claimed in any one of claims 30 to 6 1 wherein the cycle for removal
of solid particulate material is performed at room temperature.
63. A method as claimed in any one of claims 30 to 62 wherein the cycle for removal
of solid particulate material is performed for cycle times of between 2 and 30 minutes.
64. A method as claimed in any one of claims 30 to 63 which additionally comprises
separation and recovery of said solid particulate cleaning material and its re-use in
subsequent washes.
65. An apparatus as claimed in any one of claims 1 to 29 for use in small or large
scale batchwise processes.
66. A method as claimed in any one of claims 30 to 64 for use in small or large scale
batchwise processes.