U.S. patent application number 13/201504 was filed with the patent office on 2011-12-08 for cleaning apparatus.
This patent application is currently assigned to XEROS LIMITED. Invention is credited to Stephen Derek Jenkins, William George Westwater.
Application Number | 20110296628 13/201504 |
Document ID | / |
Family ID | 40548314 |
Filed Date | 2011-12-08 |
United States Patent
Application |
20110296628 |
Kind Code |
A1 |
Jenkins; Stephen Derek ; et
al. |
December 8, 2011 |
Cleaning Apparatus
Abstract
The invention provides an apparatus and method for use in the
cleaning of soiled substrates, the apparatus comprising a casing
which contains a rotatably mounted cylindrical cage concentrically
located within a rotatably mounted cylindrical drum having a
greater diameter than the basket, wherein the cage and the drum are
concentrically located within a stationary cylindrical drum having
a greater diameter than the rotatably mounted drum, wherein the
casing includes access means, allowing access to the interior of
the cylindrical basket, and wherein the rotatably mounted
cylindrical cage and the rotatably mounted cylindrical drum are
adapted to rotate independently. The method involves cleaning the
soiled substrate by treatment of the moistened substrate with a
formulation comprising solid particulate cleaning material, the
formulation being free of organic solvents, and the method being
carried out using the apparatus of the invention, and the apparatus
and method find particular application in the cleaning of textile
fabrics.
Inventors: |
Jenkins; Stephen Derek;
(Cleveland, GB) ; Westwater; William George;
(Yorkshire, GB) |
Assignee: |
XEROS LIMITED
Leeds, Yorkshire
UK
|
Family ID: |
40548314 |
Appl. No.: |
13/201504 |
Filed: |
February 17, 2010 |
PCT Filed: |
February 17, 2010 |
PCT NO: |
PCT/GB2010/050261 |
371 Date: |
August 15, 2011 |
Current U.S.
Class: |
8/137 ;
68/142 |
Current CPC
Class: |
D06F 35/00 20130101 |
Class at
Publication: |
8/137 ;
68/142 |
International
Class: |
D06L 1/20 20060101
D06L001/20; D06F 21/00 20060101 D06F021/00 |
Foreign Application Data
Date |
Code |
Application Number |
Feb 17, 2009 |
GB |
0902619.6 |
Claims
1. An apparatus for use in the cleaning of soiled substrates, said
apparatus comprising a casing which contains a rotatably mounted
cylindrical cage concentrically located within a rotatably mounted
cylindrical drum having a greater diameter than said basket,
wherein said cage and said drum are concentrically located within a
stationary cylindrical drum having a greater diameter than said
rotatably mounted drum, wherein said casing includes access means,
allowing access to the interior of said cylindrical basket, and
wherein said rotatably mounted cylindrical cage and said rotatably
mounted cylindrical drum are adapted to rotate independently.
2. An apparatus as claimed in claim 1 wherein said access means may
be closed so as to provide a substantially sealed system.
3. (canceled)
4. An apparatus as claimed in claim 1 wherein said stationary
cylindrical drum, said rotatably mounted cylindrical cage and
rotatably mounted cylindrical drum are mounted horizontally within
said casing.
5. An apparatus as claimed in claim 1 wherein said rotatably
mounted cylindrical cage comprises a plurality of perforations in
its cylindrical side walls, thereby allowing for ingress and egress
of fluids, fine particulate materials and discrete particulate
materials.
6-8. (canceled)
9. An apparatus as claimed in claim 1 wherein said rotatably
mounted cylindrical drum comprises a plurality of perforations in
its cylindrical side walls, thereby allowing for ingress and egress
of fluids and fine particulate materials but preventing the ingress
or egress of discrete particulate materials.
10-11. (canceled)
12. An apparatus as claimed in claim 1 wherein said rotatably
mounted cylindrical cage has a capacity in the region of 50-500
litres.
13-16. (canceled)
17. An apparatus as claimed in claim 1 wherein rotation of said
rotatably mounted cylindrical cage and said rotatably mounted
cylindrical drum is effected by use of drive means, wherein
operation of said drive means is optionally effected by control
means.
18-20. (canceled)
21. An apparatus as claimed in claim 1 which comprises circulation
means.
22. An apparatus as claimed in claim 21 wherein the inner surface
of the cylindrical side walls of said rotatably mounted cylindrical
drum comprises a multiplicity of spaced apart circulation paddles
to serve as circulation means.
23. (canceled)
24. An apparatus as claimed in claim 1 wherein said apparatus
additionally comprises separation means, wherein said separation
means optionally comprises a plurality of reservoir baffles which
are fixedly mounted between the cylindrical walls of said rotatably
mounted cylindrical cage and said rotatably mounted cylindrical
drum.
25-26. (canceled)
27. An apparatus as claimed in claim 1 which comprises suction
means.
28-32. (canceled)
33. An apparatus as claimed in claim 1 which additionally comprises
recirculation means, wherein said recirculation means optionally
comprises ducting connecting said suction means and said rotatably
mounted cylindrical drum, said ducting comprises separating means
and purification means and said separating means comprises a
cyclone and said purification means comprises a filter.
34-36. (canceled)
37. A method for cleaning a soiled substrate, said method
comprising the treatment of the moistened substrate with a
formulation comprising solid particulate cleaning material, said
formulation being free of organic solvents, wherein said method is
carried out in an apparatus according to claim 1.
38. A method for cleaning a soiled substrate, said method
comprising the steps of: (a) loading at least one soiled substrate
into an apparatus as claimed in claim 1 via the access means, said
apparatus containing a solid particulate cleaning material located
in at least one of the rotatably mounted cylindrical cage and the
rotatably mounted cylindrical drum; (b) closing the access means so
as to provide a substantially sealed system; (c) operating the
apparatus for a first cycle, wherein said rotatably mounted
cylindrical cage and said rotatably mounted cylindrical drum are
both caused to rotate in the same direction, wherein said first
cycle comprises a wash cycle; (d) operating the apparatus for a
second cycle, wherein said rotatably mounted cylindrical cage
continues to rotate in the same direction, but said rotatably
mounted cylindrical drum (i) is caused to initially cease rotation
and (ii) subsequently is subjected to incremental movements in the
opposite direction to the cage, whereby the solid particulate
cleaning material is retained between successive pairs of reservoir
baffles until removal of the material from the cage has been
completed, wherein said second cycle comprises a cycle for removal
of said solid particulate cleaning material from said at least one
substrate; (e) removing the cleaned at least one substrate from the
apparatus; and (f) removing any remaining solid particulate
cleaning material.
39-41. (canceled)
42. A method as claimed in any claim 37 wherein said at least one
soiled substrate comprises at least one textile fibre garment and
said solid particulate cleaning material comprises a multiplicity
of polymeric particles, and wherein said solid particulate cleaning
material comprises at least one cleaning material, and said soiled
substrate is moistened by wetting with water prior to commencing
cleaning operations.
43-57. (canceled)
Description
FIELD OF THE INVENTION
[0001] The present invention relates to the cleaning of substrates
using a solvent-free cleaning system which requires the use of only
limited quantities of water. Most particularly, the invention is
concerned with the cleaning of textile fibres by means of such a
system, and provides an apparatus adapted for use in this
context.
BACKGROUND TO THE INVENTION
[0002] Dry cleaning is a process of major importance within the
textile industry, specifically for the removal of hydrophobic
stains which are difficult to remove by traditional aqueous washing
methods. However, most commercial dry cleaning systems currently
employ toxic and potentially environmentally harmful halocarbon
solvents, such as perchloroethylene. The use of these solvents, and
the need for their storage, treatment, and/or disposal creates
major effluent problems for the industry, and this inevitably
increases costs.
[0003] More recently, the use of carbon dioxide as an alternative
to such systems has been reported. Thus, systems which employ
liquid carbon dioxide in combination with surfactants containing a
CO.sub.2-philic functional moiety have been proposed, whilst the
use of more conventional surfactants in combination with
supercritical carbon dioxide has also been disclosed. However, a
major problem with carbon dioxide is its lower solvent power
relative to other solvents. Furthermore, some of the procedures
rely on the use of high pressure systems, and this is a clear
disadvantage, since it presents an inherent safety risk, thereby
lessening the attractiveness of the procedures.
[0004] Even more widely used are aqueous cleaning processes, which
do not suffer from the disadvantages associated with the use of
potentially toxic solvents or high pressure carbon dioxide systems,
but still create very significant environmental difficulties in
terms of the vast quantities of aqueous effluent which are
generated. As a consequence, the use of these aqueous cleaning
processes necessitates the development of sophisticated waste
treatment systems.
[0005] In the light of the difficulties and disadvantages
associated with traditional aqueous and dry cleaning processes, the
present inventors have previously devised a new approach to the
problem, which allows the deficiencies demonstrated by the methods
of the prior art to be overcome and provides a process for the
cleaning of substrates, particularly for the cleaning of textile
fibres. The method which is provided eliminates the requirement for
the use of, on the one hand, potentially harmful solvents or carbon
dioxide in either the liquid or supercritical state or, on the
other hand, large volumes of aqueous fluids, but is still capable
of providing an efficient means of cleaning and stain removal,
whilst also yielding economic and environmental benefits. The
process employs a cleaning formulation which is essentially free of
organic solvents and requires the use of only limited amounts of
water.
[0006] Thus, in WO-A-2007/128962 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
nylon, most preferably in the form of nylon chips.
[0007] The use of this cleaning method, however, presents a
requirement for the cleaning chips to be efficiently separated from
the cleaned substrate at the conclusion of the cleaning operation,
and it is this issue that is addressed by the present invention. It
has been the concern of the present inventors to provide an
apparatus which facilitates the efficient cleaning of soiled
substrates using the method of WO-A-2007/128962, but which
additionally allows for the efficient separation of the substrate
from the cleaning media at the conclusion of the cleaning process.
This has now been achieved by means of the apparatus of the present
invention, which provides a novel design requiring the use of two
internal drums capable of independent rotation, and which finds
application in both industrial and domestic cleaning processes.
SUMMARY OF THE INVENTION
[0008] 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 casing which contains a
rotatably mounted cylindrical cage concentrically located within a
rotatably mounted cylindrical drum having a greater diameter than
said basket, wherein said cage and said drum are concentrically
located within a stationary cylindrical drum having a greater
diameter than said rotatably mounted drum, wherein said casing
includes access means, allowing access to the interior of said
cylindrical basket, and wherein said rotatably mounted cylindrical
cage and said rotatably mounted cylindrical drum are adapted to
rotate independently.
[0009] 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.
[0010] Said stationary cylindrical drum, rotatably mounted
cylindrical cage and rotatably mounted cylindrical drum may be
mounted vertically within said casing but, most preferably, are
mounted horizontally within said casing. Consequently, in the
preferred embodiment of the invention, said access means is located
in the front of the apparatus, providing a front-loading facility.
When the stationary cylindrical drum, rotatably mounted cylindrical
cage and rotatably mounted cylindrical drum are vertically mounted
within the casing, 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 stationary cylindrical drum, rotatably
mounted cylindrical cage and rotatably mounted cylindrical drum are
mounted horizontally within said casing.
[0011] Said rotatably mounted cylindrical cage and said rotatably
mounted cylindrical drum are adapted to rotate independently, such
that said cage and said drum may both rotate simultaneously in the
same or in opposite directions. Alternatively, one of said cage or
said drum may rotate whilst the other is at rest.
[0012] Rotation of said rotatably mounted cylindrical cage and said
rotatably mounted cylindrical drum is effected by use of drive
means, which typically comprises electrical drive means, in the
form of an electric motor, adapted to drive said cage and said drum
independently or simultaneously in the same or in opposite
directions. Operation of said drive means is effected by control
means which may be programmed by an operative.
[0013] Said stationary cylindrical drum is a similar feature to
that which is found in conventional commercial and domestic washing
machines, and is adapted to provide the same functions as in said
machines. Thus, said stationary drum is connected to the standard
plumbing features of the apparatus and may additionally comprise
means for circulating air within said apparatus, 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 the temperature and humidity
levels within the apparatus, and for communicating this information
to the control means.
[0014] Said rotatably mounted cylindrical cage comprises a
plurality of perforations in its cylindrical side walls, thereby
allowing for ingress and egress of fluids, fine particulate
materials and discrete particulate materials. Said perforations
typically have a diameter of from 5-10 mm, preferably from 6-9 mm,
most preferably from 7-8 mm.
[0015] The cylindrical side walls of the rotatably mounted
cylindrical drum are also perforated to permit the ingress and
egress of fluids and fine particulate materials, but are adapted so
as to prevent the ingress or egress of discrete particulate
materials. Consequently, the perforations typically have a diameter
of less than 5 mm, most preferably less than 2.5 mm.
[0016] Said rotatably mounted cylindrical cage is of the size which
is to be found in most commercially available washing machines and
tumble driers, and typically has a capacity in the region of 50-500
litres. Generally said cage comprises a cylinder with a diameter in
the region of 40-100 cm, preferably 50-90 cm, most preferably 60-80
cm, and a length of between 30 and 100 cm, preferably between 40
and 90 cm, most preferably from 50 to 80 cm.
[0017] Said rotatably mounted cylindrical drum is concentrically
located outside said rotatably mounted cylindrical basket and,
consequently, has greater cross-sectional dimensions than said
basket. Thus, typically said drum comprises a cylinder with a
diameter in the region of 50-120 cm, preferably 60-100 cm, most
preferably 70-90 cm, and a length of between 30 and 100 cm,
preferably between 40 and 90 cm, most preferably from 50 to 80
cm.
[0018] Said stationary cylindrical drum is concentrically located
outside said rotatably mounted cylindrical drum and, consequently,
has greater cross-sectional dimensions, and generally slightly
greater length, than said rotatably mounted drum. Thus, typically
said drum comprises a cylinder with a diameter in the region of
55-140 cm, preferably 65-105 cm, most preferably 75-95 cm, and a
length of between 31 and 105 cm, preferably between 41 and 95 cm,
most preferably from 51 to 85 cm.
[0019] 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. Ideally, these polymeric particles should 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 drum preferably comprises a multiplicity of
spaced apart circulation paddles, typically in the form of
oblong-shaped protrusions affixed essentially perpendicularly to
said inner surface. Said paddles are adapted so as to promote
efficient circulation of said solid particulate material. Typically
said apparatus comprises from 3 to 12 of said paddles.
[0020] Preferably, said apparatus additionally comprises separation
means located between said rotatably mounted cylindrical cage and
said rotatably mounted cylindrical drum. In a preferred embodiment
of the invention, said separation means comprises a plurality of
reservoir baffles, which are fixedly mounted between the
cylindrical walls of said rotatably mounted cylindrical cage and
said rotatably mounted cylindrical drum and are adapted so as to
facilitate controlled flow of said solid particulate material
between said cage and said drum. Most preferably, said apparatus
comprises two spaced apart crescent shaped reservoir baffles
concentrically mounted between said cage and said drum, and of
essentially equal length to said cage, arranged at opposite sides
of said cage, so as to provide spaces at two locations through
which ingress and egress of materials from said cage to said drum
may occur.
[0021] In preferred embodiments of the invention, there is also
provided suction means, in order to facilitate the efficient
removal of residual solid particulate material at the conclusion of
the cleaning operation. Preferably, said suction means comprises a
suction chamber. Preferably, said suction chamber is located in the
base of said apparatus, below said stationary cylindrical drum,
said rotatably mounted cylindrical cage and said rotatably mounted
cylindrical drum and is adapted to operate at the conclusion of the
cleaning operation.
[0022] Preferably, said suction chamber comprises a chamber which
may be extended out of the body of the apparatus, such that it may
be located beneath the access means through which cleaned substrate
is removed from the apparatus of the invention, in order that
residual solid particulate material may be collected therein, as a
consequence of the combined effects of gravity and applied suction.
Typically, suction is applied by means of a vacuum pump, and is
activated when said suction chamber is extended out of the body of
the apparatus.
[0023] Optionally, said suction means may also comprise localised
suction means, typically in the form of a suction gun, which may be
directed to localised parts of the cleaned substrate so as to
remove remaining residual solid particulate cleaning material.
Preferably, said suction gun comprises a headpiece including an
aperture attached to flexible tubing, though which suction may be
applied.
[0024] Preferred embodiments of the invention additionally comprise
recirculation means, thereby facilitating recirculation of said
solid particulate material from said suction means to said
rotatably mounted cylindrical drum, for re-use in cleaning
operations. Preferably, said recirculation means comprises ducting
connecting said suction means and said rotatably mounted
cylindrical drum. More preferably, said ducting comprises
separating means for separating said solid particulate material
from debris removed from the soiled substrate during the cleaning
process, and purification means, adapted to remove debris from the
air flow and permit expulsion of the filtered air stream to the
atmosphere. Typically, said separating means comprises a cyclone,
and said purification means comprises a filter.
[0025] In operation, during a typical cycle, said rotatably mounted
cylindrical cage and said rotatably mounted cylindrical drum are
adapted to rotate independently in the same direction during the
cleaning process. Thus, solid particulate material which falls
through the perforations in the bottom of said rotatably mounted
cylindrical cage and between said reservoir baffles into said
rotatably mounted cylindrical drum is carried by means of said
circulation paddles to the top side of said rotatably mounted
cylindrical cage, wherein it is caused, by means of gravity to fall
between said reservoir baffles and the perforations in said
rotatably mounted cylindrical cage, back into said cage, thereby to
continue the cleaning operation.
[0026] At the completion of the cleaning cycle, rotation of said
rotatably mounted cylindrical cage continues, whilst rotation of
said rotatably mounted cylindrical cage is stopped, thus allowing
said solid particulate matter to fall through the perforations in
the bottom of said rotatably mounted cylindrical cage and between
said reservoir baffles into said rotatably mounted cylindrical
drum, where it is allowed to collect. In practice, it is found that
the amount of said solid particulate material which accumulates in
the bottom of said rotatably mounted cylindrical drum is too great
if this is allowed to remain at rest. Consequently means for
removal of the material from this location must be provided.
Optionally, this may be in the form of an associated reservoir,
wherein the material may temporarily be transferred. Preferably,
however, the material is removed by frequent changes in the
direction of rotation of the drum, or by incremental movement of
the drum in the opposite direction to the cage, whereby the solid
particulate material is retained between successive pairs of
reservoir baffles until removal of the material from the cage has
been completed.
[0027] Thus, 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 moistened substrate with a
formulation comprising solid particulate cleaning material, said
formulation being free of organic solvents, wherein said method is
carried out in an apparatus according to the first aspect of the
invention.
[0028] Preferably, said method comprises the steps of: [0029] (a)
loading at least one soiled substrate into an apparatus according
to the first aspect of the invention via the access means, said
apparatus containing a solid particulate cleaning material located
in at least one of the rotatably mounted cylindrical cage and the
rotatably mounted cylindrical drum; [0030] (b) closing the access
means so as to provide a substantially sealed system; [0031] (c)
operating the apparatus for a first cycle, wherein said rotatably
mounted cylindrical cage and said rotatably mounted cylindrical
drum are both caused to rotate in the same direction, wherein said
first cycle comprises a wash cycle; [0032] (d) operating the
apparatus for a second cycle, wherein said rotatably mounted
cylindrical cage continues to rotate in the same direction, but
said rotatably mounted cylindrical drum (i) is caused to initially
cease rotation and (ii) subsequently is subjected to incremental
movements in the opposite direction to the cage, whereby the solid
particulate cleaning material is retained between successive pairs
of reservoir baffles until removal of the material from the cage
has been completed, wherein said second cycle comprises a cycle for
removal of said solid particulate cleaning material from said at
least one substrate; [0033] (e) removing the cleaned at least one
substrate from the apparatus; and [0034] (f) removing any remaining
solid particulate cleaning material.
[0035] Preferably, said remaining solid particulate material is
removed by shaking the at least one substrate in the vicinity of
suction means, preferably comprising a suction chamber, wherein
said remaining solid particulate material is collected. Most
particularly, said step of removing any remaining solid particulate
cleaning material also includes the step of applying localised
suction means to localised parts of the cleaned substrate, said
localised suction means preferably comprising a suction gun.
[0036] Throughout the description and claims of this specification,
the words "comprise" and "contain" and variations of the words, for
example "comprising" and "comprises", means "including but not
limited to", and is not intended to (and does not) exclude other
moieties, additives, components, integers or steps.
[0037] 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.
[0038] 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.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] The invention will now be further illustrated by reference
to the following drawings, wherein:
[0040] FIG. 1 shows the apparatus according to the invention prior
to loading a soiled substrate comprising garments into the
apparatus;
[0041] FIG. 2 illustrates the apparatus according to the invention
during the wash cycle of the method of the invention;
[0042] FIG. 3 depicts the apparatus according to the invention
during the cycle of the method of the invention for removal of said
solid particulate cleaning material;
[0043] FIG. 4 shows the apparatus according to the invention during
unloading of the cleaned substrate;
[0044] FIG. 5 illustrates the step of removing remaining solid
particulate cleaning material from the substrate using the suction
chamber;
[0045] FIG. 6 depicts the use of a suction gun for removal of
further remaining solid particulate cleaning material from
localised parts of the cleaned substrate.
[0046] FIG. 7 shows a recirculation system for collecting solid
particulate cleaning material and returning it to the rotatably
mounted cylindrical cage and the rotatably mounted cylindrical
drum; and
[0047] FIG. 8 illustrated the action of a cyclone in separating the
solid particulate cleaning material from solid waste material
generated during the method of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0048] 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.
[0049] Most preferably, the solid particulate cleaning material
comprises a multiplicity of polymeric particles. Said polymeric
particles may comprise any of a wide range of different polymers.
Specifically, there may be mentioned polyalkenes such as
polyethylene and polypropylene, polyesters and polyurethanes.
Preferably, however, said polymeric particles comprise polyamide
particles, most particularly particles of nylon, most preferably in
the form of nylon chips or beads. Said polyamides are found to be
particularly effective for aqueous stain/soil removal, whilst
polyalkenes are especially useful for the removal of oil-based
stains. Optionally, copolymers of the above polymeric materials may
be employed for the purposes of the invention.
[0050] 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 material. Preferably, the at least one cleaning material
comprises at least one surfactant. Preferred surfactants comprise
surfactants having detergent properties. Said surfactants may
comprise anionic, cationic and/or non-ionic surfactants.
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.
[0051] Various nylon homo- or co-polymers may be used, including
Nylon 6 and Nylon 6,6. 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.
[0052] 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. The particles may have smooth or irregular
surface structures and can be of solid or hollow construction.
Particles are preferably of such a size as to have an average mass
in the region of 5-50 mg, more preferably from 10-30 mg. In the
case of the most preferred chips, the preferred average particle
diameter is in the region of from 1.5-6.0 mm, more preferably from
2.0-5.0 mm, most preferably from 2.5-4.5 mm, and the length of the
cylindrical chips is preferably in the range from 2.0-6.0 mm, more
preferably from 3.0-5.0 mm, and is most preferably in the region of
4.0 mm.
[0053] Prior to treatment according to the method of the invention,
the soiled substrate is moistened by wetting with water, in order
to provide additional lubrication to the cleaning system and
thereby improve the transport properties within 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. Most conveniently, the
substrate may be wetted simply by contact with mains or tap water.
Preferably, the wetting treatment is carried out so as to achieve a
substrate to water ratio of between 1:0.1 to 1:5 w/w; more
preferably, the ratio is between 1:0.2 and 1:2, with particularly
favourable results having been achieved at ratios such as 1:0.2,
1:1 and 1:2. However, in some circumstances, successful results can
be achieved with substrate to water ratios of up to 1:50, although
such ratios are not preferred in view of the significant amounts of
effluent which are generated.
[0054] The method of the invention has the advantage that, other
than this aqueous treatment, it is carried out in the absence of
added solvents--most notably in the absence of organic
solvents--and, consequently, it shows distinct advantages over the
methods of the prior art in terms of safety and environmental
considerations, as well as in economic terms. However, whilst the
formulation employed in the claimed method is free of organic
solvents, in that no such solvents are added to the formulation, it
will be understood that trace amounts of such solvents may
inevitably be present in the polymeric particles, the substrate,
the water, or other additives, such as cleaning materials, so it is
possible that the cleaning formulations and baths may not be
absolutely free of such solvents. However, such trace amounts are
insignificant in the context of the present invention, since they
do not have any impact on the efficiency of the claimed process,
nor do they create a subsequent effluent disposal problem and the
formulation is, therefore, seen to be essentially free of organic
solvents.
[0055] 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.
[0056] In the method according to the second aspect of the
invention, the ratio of solid particulate cleaning material to
substrate is based on a nominal "liquor ratio" in terms of a
conventional dry cleaning system, with the preferred ratio being in
the range of from 30:1 to 0.1:1 w/w, preferably in the region of
from 10:1 to 1:1 w/w, with particularly favourable results being
achieved with a ratio of between 5:1 and 1:1 w/w, and especially at
around 4:1 w/w. Thus, for example, for the cleaning of 5 g of
fabric, 20 g of polymeric particles, optionally coated with
surfactant, would be employed.
[0057] 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 are very much in line
with those which apply to the conventional dry cleaning of textile
fibres and, as a consequence, are generally determined by the
nature of the fabric and the degree of soiling. Thus, typical
procedures and conditions for the wash cycle are in accordance with
those which are well known to those skilled in the art, with
fabrics generally being treated according to the method of the
invention at, for example, temperatures of between 30 and
90.degree. C. for a duration of between 20 minutes and 1 hour in
the substantially sealed system provided by the apparatus according
to the first aspect of the invention.
[0058] The cycle for removal of solid particulate material may 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 15 minutes.
[0059] In the embodiment of the invention wherein the formulation
comprises at least one cleaning material, it is preferred that the
polymeric particles should be coated with the at least one
surfactant, in order to achieve a more level distribution of the
said surfactant on the particles and, consequently, on the
substrate, as the particles contact the substrate during the
cleaning process. Typically, this coating process requires that the
polymeric particles should be mixed with 0.5%-10%, preferably
1%-5%, most preferably around 2% of the at least one surfactant,
and the resulting mixture held at a temperature of between
30.degree. and 70.degree. C., preferably 40.degree. and 60.degree.
C., most preferably in the region of 50.degree. C., for a time of
between 15 and 60 minutes, preferably between 20 and 40 minutes,
with the most satisfactory results being obtained when the
treatment is carried out for approximately 30 minutes.
[0060] The results obtained are very much in line with those
observed when carrying out conventional aqueous and 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 method
also finds application in wash-off procedures applied to textile
fibres subsequent to dyeing processes, and in scouring processes
which are used in textile processing for the removal of dirt,
sweat, machine oils and other contaminants which may be present
following processes such as spinning and weaving. The attendant
drawbacks associated with the use of solvents in conventional dry
cleaning processes, in terms of both cost and environmental
considerations, are avoided, whilst the volumes of water required
are significantly lower than those associated with the use of
conventional aqueous washing procedures, again offering significant
advantages in terms of cost and environmental benefits.
[0061] The method of the invention has been shown to be
particularly successful in the removal of cleaning material from
the cleaned substrate after processing and tests with cylindrical
nylon chips comprising nylon 6,6 polymer have indicated bead
removal efficacy of 99.95% from a 5 minute cycle.
[0062] Additionally, it has been demonstrated that re-utilisation
of the polymer particles is possible, and that particles can be
satisfactorily re-used in the cleaning procedure, although some
deterioration in performance is generally observed following three
uses of the particles. When re-using particles, optimum results are
achieved when using particles coated with the at least one coating
material which are then re-coated prior to re-use.
[0063] Referring to the figures provided herewith, there is seen in
FIG. 1 an apparatus 1 according to the invention comprising a
casing 2 and door 3 including window 4, and housed within the
casing is a rotatably mounted cylindrical cage 5 having
perforations 6. With the door 3 in the open position, garment 7 may
be placed in rotatably mounted cylindrical cage 5.
[0064] FIG. 2 provides an illustration of apparatus 1 during the
wash cycle wherein garments 7 are in the rotatably mounted
cylindrical cage 5 which is rotating in the direction of arrows A,
with the rotatably mounted cylindrical drum 8 rotating in the same
direction, as indicated by arrows B. Nylon chips 9 are also in the
rotatably mounted cylindrical cage 5 and fall through the
perforations 6 in the bottom of said cage 5 through the lower gap
between reservoir baffles 10 into the rotatably mounted cylindrical
drum 8, and are then carried by means of circulation paddles 11 by
rotation of the drum 8 to the top side of the rotatably mounted
cylindrical cage 5, thereby re-entering said cage via the upper gap
between reservoir baffles 10 to again take part in the wash cycle.
The stationary cylindrical drum (not shown) is of greater diameter
than said rotatably mounted cylindrical cage 5 and said rotatably
mounted cylindrical drum 8, and located concentrically around said
rotatably mounted cylindrical drum.
[0065] In FIG. 3, there is shown the chip removal cycle, wherein
chips 9 in the rotatably mounted cylindrical cage 5, rotating in
the direction of arrows A, fall through the perforations 6 in the
bottom of the cage 5 through the lower gap between reservoir
baffles 10 into the rotatably mounted cylindrical drum 8. Drum 8
moves incrementally in the direction of arrow C, opposite to the
direction of rotation of cage 5, thereby allowing chips 9 to be
retained between circulation paddles 11 in the space between drum 8
and reservoir baffles 10.
[0066] At the conclusion of the wash and chip removal cycles, as
shown in FIG. 4, the door 3 may be opened to allow removal of
garments 7. At the same time, suction chamber 12, incorporating
garment mesh 13, which retains the garments 7 but allows chips to
fall to the bottom of the chamber, is also opened, to facilitate
removal of remaining chips attached to garments 7.
[0067] As seen from FIG. 5, the garments 7 may be shaken to cause
the remaining chips 9 to become detached and collected, by means of
the applied suction, in the suction chamber 12.
[0068] FIG. 6 illustrates the use of a suction gun comprising a
headpiece 14 and flexible tubing 15 in the removal of remaining
cleaning chips from shirt pocket 16.
[0069] Turning to FIG. 7, there is illustrated a recirculation
system comprising ducting 17, 18, 19 cyclone 20, filter 21 and
exhaust pipe 22. Thus, in operation, nylon chips are collected in
suction chamber 12 and transferred via ducting 17 to cyclone 20,
wherein lint and other lighter solid particulate material is
separated and exits the system via ducting 18, filter 21 and
exhaust pipe 22, whilst the heavier nylon chips fall through
ducting 19, and are thereby returned to the rotatably mounted
cylindrical drum 8.
[0070] Finally, in FIG. 8 can be seen the action of cyclone 20,
wherein the mixture of nylon chips and other lighter solid
particulate material enters to cyclone through ducting 17 and is
separated by the action of the cyclone, such that the lighter
material 23 exits via ducting 18, whilst the nylon chips 9 fall
through ducting 19.
[0071] The method of the invention will now be exemplified, though
without in any way limiting the scope of the invention, by
reference to the following examples:
EXAMPLES
[0072] Experiments were conducted in order to ascertain cleaning
efficiency using the apparatus and method according to the
invention.
Example 1
[0073] The polymer particles comprised cylindrical nylon chips
comprising Nylon 6,6 polymer having a molecular weight in the
region of 15000-16000 Daltons, with average dimensions of 4 mm in
length and 2-3 mm in diameter, and an average particle weight of
30-40 mg.
[0074] The fabric to be cleaned comprised soiled and stained Nylon
6,6 fibres, and the wetted dyed fabric was loaded into an apparatus
according to the invention containing 75 g (air dry mass) of
polymer particles. The temperature was raised to 40.degree. C. and
maintained at 40.degree. C. for 10 minutes, then increased to
70.degree. C. at a rate of 2.degree. C. per minute, and then
maintained at 70.degree. C. for 20 minutes to complete the wash
cycle, after which time the cycle for removal of the nylon chips
was operated for 5 minutes before the fabric was removed from the
apparatus, rinsed and dried. Complete removal of the soiling and
staining was achieved and the fabric was found to be free of
residual nylon chips.
Example 2
[0075] The fabric to be cleaned comprised a soiled cloth of
mercerised cotton stained with coffee in an aqueous transport
medium. This pre-soiled fabric sample was placed in an apparatus
according to the invention containing 75 g (air dry mass) of
polymer particles comprising cylindrical chips of Nylon 6,6
polymer, with average dimensions of 4 mm in length and 4 mm in
diameter. The pre-soiled fabric sample was wetted with tap water
before commencement of cleaning to give a substrate to water ratio
of 1:1. The apparatus was operated on the cleaning cycle for 30
minutes to a maximum of 70.degree. C. with a cooling stage at the
end of the cycle, then the cycle for removal of the nylon chips was
operated for 5 minutes. Once this was complete, the cleaned fabric
was removed from the apparatus and dried flat. The degree of
staining of the cloth was very significantly reduced following the
cleaning process.
Example 3
[0076] The fabric to be cleaned comprised a soiled cloth of
mercerised cotton stained with city street dirt in an aqueous
transport medium. This pre soiled fabric sample was placed in an
apparatus according to the invention with 75 g (air dry mass) of
polymer particles comprising cylindrical chips of Nylon 6,6
polymer, with average dimensions of 4 mm in length and 4 mm in
diameter. The pre-soiled fabric sample was wetted with tap water
before commencement of cleaning to give a substrate to water ratio
of 1:2. The apparatus was operated on the cleaning cycle for 30
minutes to a maximum of 70.degree. C. with a cooling stage at the
end of the cycle, then the cycle for removal of the nylon chips was
operated for 5 minutes. Once this was complete, the cleaned fabric
was removed from the apparatus and dried flat. A significant
reduction in numbers of dirt particles was observed after the
cleaning process had taken place.
Example 4
[0077] The fabrics to be cleaned comprised soiled cloths (cotton
and polyester stained with coffee, soil, boot polish, ball point
pen, lipstick, tomato ketchup and grass). Each pre-soiled fabric
sample was placed in an apparatus according to the invention with
75 g (air dry mass) of the polymer particles (cylindrical nylon
chips comprising nylon 6,6 polymer, with average dimensions of 4 mm
in length and 4 mm in diameter). Each pre-soiled fabric sample was
wetted with mains or tap water before cleaning commenced to give a
substrate to water ratio of 1:1. The apparatus was operated on the
cleaning cycle for 30 minutes at a maximum temperature of
70.degree. C. with a cooling stage at the end of the cycle, then
the cycle for removal of the nylon chips was operated for 5
minutes. Once this was complete, the cleaned fabric was removed
from the apparatus and dried flat. In each case, the degree of
staining of the fabric was significantly reduced.
Example 5
[0078] The fabric to be cleaned comprised a soiled cloth (cotton
stained with city street dirt in an aqueous transport medium). This
pre soiled fabric sample was placed in an apparatus according to
the invention with 75 g (air dry mass) of the polymer particles
(cylindrical nylon chips comprising nylon 6,6 polymer, with average
dimensions of 4 mm in length and 4 mm in diameter). The pre-soiled
fabric sample was wetted with mains or tap water before cleaning
commenced to give a substrate to water ratio of 1:2. The apparatus
was operated on the cleaning cycle for 30 minutes to a maximum
temperature of 70.degree. C. with a cooling stage at the end of the
cycle, then the cycle for removal of the nylon chips was operated
for 5 minutes. Once this was complete, the cleaned fabric was
removed from the apparatus and dried flat. The amount of removal
was very significant was measured by the change in colour strength
values between the fabric before and after cleaning.
Example 6
[0079] The fabric to be cleaned comprised a large soiled cloth
(cotton stained with boot polish, soil, coffee and tomato ketchup).
This pre-soiled fabric sample was placed in an apparatus according
to the invention with 500 g (air dry mass) of the polymer particles
(cylindrical nylon chips comprising nylon 6,6 polymer, with average
dimensions of 4 mm in length and 4 mm in diameter). The pre-soiled
fabric sample was wetted with mains or tap water before cleaning
commenced to give a substrate to water ratio of 1:0.2. The
apparatus was operated on the cleaning cycle for 30 minutes to a
maximum temperature of 70.degree. C. with a cooling stage at the
end of the cycle, then the cycle for removal of the nylon chips was
operated for 5 minutes. Once this was complete, the cleaned fabric
was removed from the apparatus and dried. The degree of staining of
the fabric was significantly reduced.
Example 7
[0080] The fabric to be scoured comprised a greige cotton cloth.
This greige fabric sample was placed in an apparatus according to
the invention with 75 g (air dry mass) of the polymer particles
(cylindrical nylon chips comprising nylon 6,6 polymer, with average
dimensions of 4 mm in length and 4 mm in diameter). The greige
fabric sample was wetted with mains or tap water before cleaning
commenced to give a substrate to water ratio of 1:2. The apparatus
was operated on the cleaning cycle for 30 minutes to a maximum
temperature of 70.degree. C. with a cooling stage at the end of the
cycle, then the cycle for removal of the nylon chips was operated
for 5 minutes. Once this was complete, the cleaned fabric was
removed from the apparatus and dried flat. The difference in colour
between conventionally scoured fabric and the fabric cleaned using
the novel process was shown by the change in colour strength values
between the fabrics to be very significant.
Example 8
[0081] Further experiments were carried out in order to determine
the efficiency of removal of cleaning material from the substrates
after treatment with the cleaning material. The tests were carried
out using polyester/cotton shirts, since these provided more
testing substrates than cloths, due to the potential for retention
of cleaning materials in crevices and pockets.
Experiment A
[0082] A polyester/cotton shirt wetted with mains or tap water to
give a substrate to water ratio of 1:2 was loaded into an apparatus
according to the invention containing 75 g (air dry mass) of
polymer particles (cylindrical nylon chips comprising nylon 6,6
polymer, with average dimensions of 4 mm in length and 4 mm in
diameter). The apparatus was operated on the cleaning cycle for 2
minutes to ensure that the shirt was thoroughly covered with chips.
During this cycle both the inner rotatably mounted cylindrical cage
and outer rotatably mounted cylindrical drum were rotated together,
causing thorough mixing of the shirt and chips. The shirt with
chips still attached was carefully removed from the machine and
weighed as a whole. The mass of the shirt was then deducted from
the recorded weight to give the mass of chips, which was then
converted to a numerical figure showing the approximate number of
chips.
Experiment B
[0083] A polyester/cotton shirt wetted with mains or tap water to
give a substrate to water ratio of 1:2 was loaded into an apparatus
according to the invention containing 75 g (air dry mass) of
polymer particles (cylindrical nylon chips comprising nylon 6,6
polymer, with average dimensions of 4 mm in length and 4 mm in
diameter). The apparatus was operated on the cleaning cycle for 2
minutes to ensure that the shirt was thoroughly covered with chips.
During this cycle both the inner rotatably mounted cylindrical cage
and outer rotatably mounted cylindrical drum were rotated together,
causing thorough mixing of the shirt and chips. The cycle for
removal of the nylon chips was then operated for cycles of 3 and 5
minutes. In the course of these cycles, the outer rotatably mounted
cylindrical drum was kept stationary, while the inner rotatably
mounted cylindrical cage containing the shirt was rotated with
frequent changes of direction. The shirt was carefully removed from
the machine without shaking and the chips were removed and counted.
In addition, the number of chips in the pocket of the shirt was
also counted.
[0084] The results of these tests are set out in Tables 4, 5 and
6.
TABLE-US-00001 TABLE 4 Number of Chips attached to Shirt after Two
Minute Wash Cycle Trial Number of Beads 1 29000 2 23000 3 27000 4
37000 5 33000 Average 29800
TABLE-US-00002 TABLE 5 Number of Chips attached to Shirt after Two
Minute Wash Cycle and Three Minute Chip Removal Cycle Number of
Beads Trial Number of Beads in Pocket 1 247 1 2 269 0 3 112 0 4 167
0 5 133 0 Average 186 0
TABLE-US-00003 TABLE 6 Number of Chips attached to Shirt after Two
Minute Wash Cycle and Five Minute Chip Removal Cycle Trial Number
of Beads 1 6 2 11 3 3 4 38 5 17 Average 15
[0085] From the above data, the percentage removal of chips from
the shirt between the end of the wash cycle and the end of the chip
removal cycle may be calculated. The values used for the
calculation are the average number of beads after two minutes
washing and the average number of beads remaining after the chip
removal cycle, and the value is calculated from the following
formula:
Percentage removal = Number of beads after wash - Number of beads
after separation Number of beads after separation .times. 100
##EQU00001##
[0086] Using this formula, it was calculated that the percentage
removal by means of the three minute chip removal cycle was 99.38%
while the percentage removal via the five minute chip removal cycle
was 99.95%.
[0087] From further observations, it appears that the majority of
the chip removal occurs within the first few seconds of the cycle
and, whilst extended tumbling improves the efficacy, there seems to
be little value in extending the cycle beyond five minutes. The
present process achieves a satisfactory level of performance, with
good removal even from the shirt pocket.
* * * * *