U.S. patent application number 11/130713 was filed with the patent office on 2005-11-17 for device and system for improved cleaning in a washing machine.
This patent application is currently assigned to The Procter & Gamble Company. Invention is credited to Baeck, Andre Cesar, Convents, Andre Christian, Costello, Adam, Cruickshank, Graeme Duncan, Duncan, Michael, Gardner, Robb Richard, Glogowski, Mark William, Gray, Peter Gerard, Haught, John Christian, Smets, Johan, Van Steenwinckel, Pascale Claire Annick, Vernon, Paul John Edward.
Application Number | 20050252538 11/130713 |
Document ID | / |
Family ID | 35456658 |
Filed Date | 2005-11-17 |
United States Patent
Application |
20050252538 |
Kind Code |
A1 |
Vernon, Paul John Edward ;
et al. |
November 17, 2005 |
Device and system for improved cleaning in a washing machine
Abstract
A washing system for cleaning within a washing zone comprising
at least one inlet capable of fluid communication with a feed
water; at least one treatment zone in fluid communication with the
at least one inlet, said at least one treatment zone comprising a
water softening zone, an electrolysis zone, a dosing zone and
combinations thereof; and at least one outlet in fluid
communication the at least treatment zone capable of being in fluid
communication with a washing zone.
Inventors: |
Vernon, Paul John Edward;
(West Chester, OH) ; Glogowski, Mark William;
(Cleves, OH) ; Haught, John Christian; (West
Chester, OH) ; Gardner, Robb Richard; (Cincinnati,
OH) ; Costello, Adam; (North Tyneside, GB) ;
Baeck, Andre Cesar; (Bonheiden, BE) ; Convents, Andre
Christian; (Diegem, BE) ; Smets, Johan;
(Lubbeek, BE) ; Van Steenwinckel, Pascale Claire
Annick; (Weerde, BE) ; Gray, Peter Gerard;
(Brussels, BE) ; Cruickshank, Graeme Duncan;
(Newcastle upon Tyne, GB) ; Duncan, Michael;
(Northumberland, GB) |
Correspondence
Address: |
THE PROCTER & GAMBLE COMPANY
INTELLECTUAL PROPERTY DIVISION
WINTON HILL TECHNICAL CENTER - BOX 161
6110 CENTER HILL AVENUE
CINCINNATI
OH
45224
US
|
Assignee: |
The Procter & Gamble
Company
Cincinnati
OH
|
Family ID: |
35456658 |
Appl. No.: |
11/130713 |
Filed: |
May 17, 2005 |
Current U.S.
Class: |
134/94.1 ;
134/200; 68/13A |
Current CPC
Class: |
C02F 1/44 20130101; D06F
35/003 20130101; C02F 1/441 20130101; D06F 39/007 20130101; B82Y
30/00 20130101 |
Class at
Publication: |
134/094.1 ;
134/200; 068/013.00A |
International
Class: |
B08B 003/00 |
Foreign Application Data
Date |
Code |
Application Number |
May 17, 2004 |
EP |
04252837.2 |
May 17, 2004 |
EP |
04252849.7 |
May 17, 2004 |
EP |
04252846.3 |
May 17, 2004 |
EP |
04252838.0 |
May 17, 2004 |
EP |
04252853.9 |
May 17, 2004 |
EP |
04252851.3 |
May 17, 2004 |
EP |
04252845.5 |
Claims
What is claimed is:
1. A washing system for cleaning within a washing zone comprising:
a. at least one inlet capable of fluid communication with a feed
water; b. at least one treatment zone in fluid communication with
the at least one inlet, said at least one treatment zone comprising
a water softening zone, an electrolysis zone, a dosing zone and
combinations thereof; and c. at least one outlet in fluid
communication the at least treatment zone capable of being in fluid
communication with a washing zone.
2. The washing system of claim 1, wherein the washing zone is
capable of cleaning or washing substrates comprises laundry and
dishware.
3. The washing system of claim 1, wherein the water softening zone
comprises nanofiltration devices, electrodeionization devices,
electrodialysis devices, reverse-osmosis devices capacitive
deionization devices, flow-through capacitors and ion-exchange
water-softening devices and combinations thereof.
4. The washing system of claim 3, wherein the water-softening zone
comprises capacitive deionization.
5. The washing system of claim 1, wherein the at least partially
softened water comprises a conductivity of 100 .mu.S/cm or
less.
6. The washing system of claim 1, wherein at least partially
softened water comprises a soft water flux of at least about 2 L/h
at a feed water pressure from about 100 to about 1000 kP.
7. The washing system of claim 1, wherein the device and the
washing zone are housed substantially within one housing.
8. The washing system of claim 1, wherein the device and the
washing zone are independently housed.
9. The washing system of claim 1, wherein the dosing zone is
fluidly connected between the at least one inlet and at least one
outlet and capable of dispensing a fabric care composition.
10. The washing system of claim 9, further comprising a mixing zone
functionally connected between the dosing zone and the outlet
capable of at least partially mixing the fabric care composition
with a second fluid.
11. The washing system of claim 10, wherein the mixing zone
comprises in-line mixers comprising, venturi flow, direct injection
pumps, peristaltic pumps, gravity feeds, and spraying; sonic
mixers; ultrasonic mixers; and combinations thereof.
12. The washing system of claim 9, wherein from about 0.01 to about
50 grams of fabric care composition are dispensed by the dosing
zone.
13. The washing system of claim 1, comprising at least one water
softening zone and at least one electrolysis zone.
14. The washing system of claim 13, comprising: a. a first water
softening and a second water softening zone; and b. a first
electrolysis zone and a second electrolysis zones wherein the first
water softening zone is fluidly connected to the first electrolysis
zone and the second water softening zone is fluidly connected to
the second electrolysis zone.
15. The washing system of claim 1 further comprising at least one
check valve between the at least one inlet and the at least one
outlet.
16. The washing system of claim 1, further comprising at least one
sensor capable of sensing at least one water level, density,
conductivity, pH, vibration, temperature, turbidity, viscosity, and
combinations thereof.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of EP Patent Application
No. 04252837.2, filed May 17, 2004, EP Patent Application No.
04252849.7, filed May 17, 2004, EP Patent Application No.
04252846.3, filed May 17, 2004, EP Patent Application No.
04252838.0, filed May 17, 2004, EP Patent Application No.
04252853.9, filed May 17, 2004, EP Patent Application No.
04252851.3, filed May 17, 2004, EP Patent Application No.
04252845.5 and U.S. application Ser. No. 10/967,757, filed Oct. 18,
2004.
BACKGROUND OF THE INVENTION
[0002] In recent years there has been growing interest in a variety
of non-detergent based technologies for washing laundry and other
soiled substrates. For example, a number of washing machines have
been launched on the Japanese and Asian markets that make use of
electrolysis, ultrasonic or cavitation techniques to promote the
cleaning or disinfection of laundry. Typically, such machines
include at least one wash cycle characterized as `detergent-free`
and which is designed for the washing of laundry that is relatively
lightly soiled. As the washing machine manufacturers themselves
make clear, however, the machines and systems currently on the
market are of limited value for the washing of more heavily soiled
or stained items where the use of a surfactant-based detergent
product continues to be necessary to achieve acceptable cleaning
performance. Accordingly, such machines are designed and marketed
for so-called `hybrid` use with non-detergent and detergent
wash-cycles being selectable according to the severity of the
laundering task.
[0003] In terms of overall resource utilization, the non-detergent
based cleaning technologies may have the potential to save on
detergent product usage in light soil situations, but such savings
are offset to a lesser or greater extent by the operational need
for higher water and energy utilization. Thus the resource equation
is finely balanced.
[0004] One difficulty in adopting any change to cleaning
technologies relates to the enormous capital investment that has
been made worldwide in the current types of washing machine
equipment. Asking owners of this equipment to wholly replace their
machines with new machines would require significant investment by
the owners, as well as create a glut of obsolete washing machines
having limited use.
[0005] It clearly would be desirable to enhance the efficacy of
current washing machines and systems, including the newer `hybrid`
machines, so as to deliver improved washing performance across the
full range of detergent usage levels. It would also be desirable to
deliver performance improvements in the context of an overall
efficient and sustainable utilization of resources--chemical, water
and energy.
[0006] It is an object of the present invention to provide methods
and systems applicable in the field of domestic or institutional
appliances such as laundry washing machines, automatic dishwashing
machines, etc and which enable improved cleaning of a soiled
substrate or substrates across the range of detergent usage levels.
It is a further object of the invention to provide washing methods
and systems enabling more efficient usage of water, energy and
detergent product resources. It is yet another object of this
invention to provide such methods and systems that can be
retrofitted or otherwise utilized in concert with existing domestic
or institutional appliances.
SUMMARY OF THE INVENTION
[0007] The present invention relates to a washing system for
cleaning within a washing zone comprising at least one inlet
capable of fluid communication with a feed water; at least one
treatment zone in fluid communication with the at least one inlet,
said at least one treatment zone comprising a water softening zone,
an electrolysis zone, a dosing zone and combinations thereof; and
at least one outlet in fluid communication the at least treatment
zone capable of being in fluid communication with a washing zone.
In one embodiment the washing zone is capable of cleaning or
washing substrates comprises laundry and dishware. In one
embodiment the water softening zone comprises nanofiltration
devices, electrodeionization devices, electrodialysis devices,
reverse-osmosis devices capacitive deionization devices,
flow-through capacitors and ion-exchange water-softening devices
and combinations thereof. In one embodiment the water-softening
zone comprises capacitive deionization. In one embodiment the at
least partially softened water comprises a residual Ca.sup.2+
hardness of less than about 4 mmol/L. In one embodiment at least
partially softened water comprises a soft water flux of at least
about 2 L/h at a feed water pressure from about 100 to about 1000
kP. In one embodiment the device and the washing zone are housed
substantially within one housing. In one embodiment the device and
the washing zone are independently housed. In one embodiment the
dosing zone is fluidly connected between the at least one inlet and
at least one outlet and capable of dispensing a fabric care
composition. In one embodiment, the present invention further
comprises a mixing zone functionally connected between the dosing
zone and the outlet capable of at least partially mixing the fabric
care composition with a second fluid. In one embodiment the mixing
zone comprises in-line mixers comprising, venturi flow, direct
injection pumps, peristaltic pumps, gravity feeds, and spraying;
sonic mixers; ultrasonic mixers; and combinations thereof. In one
embodiment from about 0.01 to about 50 grams of fabric care
composition are dispensed by the dosing zone. In one embodiment at
least one water softening zone and at least one electrolysis zone.
In one embodiment, the washing system comprises a first water
softening and a second water softening zone; and a first
electrolysis zone and a second electrolysis zones wherein the first
water softening zone is fluidly connected to the first electrolysis
zone and the second water softening zone is fluidly connected to
the second electrolysis zone. In one embodiment, the present
invention further comprises at least one check valve between the at
least one inlet and the at least one outlet. In one embodiment, the
present invention further comprises at least one sensor capable of
sensing at least one water level, density, conductivity, pH,
vibration, temperature, turbidity, viscosity, and combinations
thereof.
DETAILED DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 comprises a first non-limiting embodiment of the
present invention.
[0009] FIG. 2 comprises a second non-limiting embodiment of the
present invention.
[0010] FIG. 3 comprises a third non-limiting embodiment of the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0011] While the specification concludes with the claims
particularly pointing and distinctly claiming the invention, it is
believed that the present invention will be better understood from
the following description.
[0012] The compositions of the present invention can include,
consist essentially of, or consist of, the components of the
present invention as well as other ingredients described herein. As
used herein, "consisting essentially of" means that the composition
or component may include additional ingredients, but only if the
additional ingredients do not materially alter the basic and novel
characteristics of the claimed compositions or methods.
[0013] All percentages and ratios used herein are by weight of the
total composition and all measurements made are at 25.degree. C.,
unless otherwise designated. An angular degree is a planar unit of
angular measure equal in magnitude to {fraction (1/360)} of a
complete revolution.
[0014] All measurements used herein are in metric units unless
otherwise specified.
[0015] The term "product" as used herein encompasses both
active-based detergent compositions suitable for washing and
cleaning of soiled substrates as well as auxiliary compositions
suitable for use after washing or in conjunction with active-based
detergents and designed to provide an ancillary substrate benefit
or effect, for example, finishing agents, rinsing agents, fabric
enhancers designed to provide post-wash fabric care benefits, and
detergent auxiliaries designed to provide post-wash surface care
benefits. The terms "product dispensing zone," "product storage
means," etc., should be construed accordingly.
[0016] The term "feed water" as used herein encompasses water
directly from the mains including municipally available water and
ground water, from the mains or used-water reservoir such as a
recycle reservoir used for storage of recycled water, a storage
tank, or from a combination thereof.
[0017] The term "laundry" as used herein encompasses woven and
non-woven fabric. Non-limiting uses for this fabric include
clothing, bedding, towels, and the like.
[0018] The term "washing zone" as used herein encompasses the
volume whereby laundry, and/or product and/or a softened water are
present to perform cleaning and/or washing. An example of a washing
zone includes the volume created by the drum of an automatic
washing machine.
[0019] It has now surprisingly been discovered that the washing
system of the present invention provides improved cleaning and
washing efficacy. Further, the washing systems can be utilized for
a variety of cleaning or washing duties. According to a first
aspect of the present invention, there is provided a washing system
for cleaning within a washing zone comprising at least one inlet
capable of fluid communication with a feed water; at least one
treatment zone in fluid communication with the at least one inlet,
said at least one treatment zone comprising a water softening zone,
an electrolysis zone, a dosing zone, and/or combinations thereof;
and at least one outlet in fluid communication with the at least
one treatment zone capable of being in fluid communication with a
washing zone.
[0020] In one embodiment, it is contemplated that the washing zone
and the washing system of the present invention are independently
housed. Such an embodiment is contemplated with washing systems
that are at the point-of-use. In one non-limiting example, it is
contemplated that the water-softening zone of the present invention
is located in a different housing than the washing zone. The
water-softening zone is fluidly connected between the feed water
and the inlet of the washing zone. In such an embodiment, its is
contemplated that existing devices utilizing feed water, including
washing zones comprising washing machines and automatic dishwashing
machines, water heaters, as well as "whole-house" inlet streams may
be retrofitted and/or adapted to have such water softening zones
present to treat feed water from the water supply.
[0021] In another embodiment, it is also contemplated that the
washing systems of the present invention and the washing zone are
contained substantially within one housing. Without wishing to be
bound by theory, it is believed that by housing the washing systems
of the present invention and the washing zone substantially within
one housing minimises any plumbing or fluid connections necessary
among the elements of the washing system. Also, housing the washing
systems of the present invention and the washing zone substantially
within one housing minimizes the volume and/or space required.
[0022] The washing systems of the invention can take the form of an
integral water-softening and washing appliance wherein the
water-softening zone and washing zone are built into and form part
of a single appliance with the two zones in fluid communication
with one another via the conduits of the appliance. In another
embodiment, the washing system comprises a water-softening
appliance and a washing appliance in hyphenated form, whereby the
water-softening appliance and its associated water-softening zone
forms a stand-alone unit that can be either permanently or
temporarily fitted to the feed water inlet conduits of the washing
appliance as required by the user, any power supply required for
the water-softening appliance being taken either from the power
supply for the washing appliance or separately from the mains power
supply.
[0023] Systems and devices of the present invention are also
advantageous in that water softening takes place without the use of
ion exchange resins. Also, the increased cleaning benefit produced
by the present invention results in less water/energy use to
achieve an equivalent cleaning benefit versus water not treated by
the present invention.
[0024] Water-Softening Zone
[0025] According to the invention, the washing systems herein
comprise a water-softening zone. In the systems and methods of the
invention, the water-softening zone comprises one or more devices
comprising nanofiltration, electrodeionization, electrodialysis,
reverse-osmosis, ion-exchange, and capacitive deionization
water-softening devices and combinations thereof. In one
embodiment, the water-softening zones can include those disclosed
in the commonly-assigned and co-filed patent application in the
name of Baeck, Convents and Smets, Applicant's reference number
CM2849F, said application being incorporated by reference
herein.
[0026] In one embodiment, the water softening zone is effective to
soften the water forming at least partially softened water to a
residual Ca.sup.2+ hardness of less than about 4 mmol/L, in another
embodiment less than about 2 mmol/L, in yet another embodiment less
than about 1 mmol/L, in still another embodiment from about 4
mmol/L to about 0.01 mmol/L, in yet still another embodiment from
about 2 mmol/L to about 0.05 mmol/L, in even still another
embodiment from about 1 mmol/L to about 0.1 mmol/L.
[0027] The specific conductance depends on the total concentration
of the dissolved ionized substances, i.e., the ionic strength of a
water sample. As used herein, it is an expression of the ability of
the water to conduct an electric current. For example, freshly
distilled water has a conductance of 0.5-2 .mu.S/cm, whereas that
of potable water generally is 50-1500 .mu.S/cm. The method of
determining the specific conductance in the present invention
utilizes the following test: ASTM D5391-99 (2005): Standard Test
Method for Electrical Conductivity of Flowing High Purity Water
Samples.
[0028] In one embodiment, the water softening zone is effective to
soften the water forming at least partially softened water to a
specific conductance of less than about 200 .mu.S/cm, in another
less than about 150 .mu.S/cm, in yet another embodiment less than
about 100 .mu.S/cm, in another less than 75 .mu.S/cm, in another
less than 50 .mu.S/cm, in still another embodiment from about 0.01
.mu.S/cm to about 200 .mu.S/cm, in yet still another embodiment
from about 0.1 .mu.S/cm to about 100 .mu.S/cm, in even still
another embodiment from about 1 .mu.S/cm to about 50 .mu.S/cm.
[0029] Without wishing to be bound by theory, it is believed that
the water softening zone will remove ionic species, including, but
not limited to cationic species, anionic species, zwitterionic
species, amphoteric species and combinations thereof. Such cationic
species include, but are not limited to, calcium, iron, magnesium,
manganese, sodium and mixtures thereof. Such anionic species
include, but are not limited to, chlorine, fluorine, carbonate,
sulphate, and mixtures thereof.
[0030] Downstream of the water-softening zone and in fluid
communication therewith, the washing system can additionally
comprise a softened water reservoir for storing and delivering at
least partially softened water to the washing zone.
[0031] Without wishing to be bound by theory, it is believed that
the water-softening zone forms an at least partially softened
water. The at least partially softened water, when transferred to
the washing zone, increases the efficacy of any product added to
the washing zone. Further, it is believed that the at least
partially softened water lengthens the usable life of components of
the washing system, as the use of at least partially softened water
reduces and/or prevents the build up of hard water deposits,
scales, and the like resulting in cleaner washing system
components.
[0032] In another embodiment, the water-softening zone utilizes
capacitive deionization. Capacitive deionization units utilize
charged electrodes for softening of the water. Capacitive
deionization with electrodes is capable of removing ionic species
and other impurities from water without the addition of other ions
as is typical of an ion exchange water softener. Other forms of
capacitive deionization include flow through capacitors which
utilize similar fundamental physics. For the purposes of this
invention capacitive deionization units include flow-thorough
capacitors. Without wishing to be bound by theory, water is passed
between electrodes kept at a low potential difference and/or
voltage. Ionic species present in the water travel to its
oppositely charged electrode. When the electrodes become saturated
with ionic species, the electrodes are electrostatically
regenerated, and ionic species are expelled as a waste electrolyte
stream. Electrode regeneration involves periodically purging the
electrodes of ionic species by reversing electrode polarity and
flushing with water to form a waste electrolyte stream or by
grounding the plates and flushing them with water to form a waste
electrolyte stream. Further, the electrodes can be regenerated of
adsorbed materials by contacting the electrodes with acid streams
or base streams. In one embodiment, acid streams and base streams
are generated by an electrolysis zone, as discussed herein.
[0033] In one embodiment, the electrodes of the capacitive
deionization units are made from carbon aerogels. Carbon aerogel
electrodes are found in U.S. Pat. No. 6,309,532 to Tran et el.
Carbon-aerogel electrodes have excellent chemical stability and a
very high surface area per unit volume.
[0034] In one embodiment, carbon aerogels are made utilizing
various carbon systems. These systems are often, though not
necessarily made by pyrolisis. These carbon systems include, but
are not limited to, resorcinol/formaldehyde
resorcinol/phenol/formaldehyde,
hydroquinone/resorcinol/formaldehyde,
phloroglucinol/resorcinol/formaldeh- yde,
catechol/resorcinol/formaldehyde, polyvinyl chloride,
phenol/formaldehyde, epoxidized phenol/formaldehyde, polyvinyl
chloride, phenolibenzaldehyde, oxidized polystyrene, polyfurfuryl
alcohol, polyvinyl alcohol, polyacrylonitrile, polyvinylidene
chloride, cellulose, polybutylene, cellulose acetate,
melamine/formaldehyde, polyvinyl acetate, ethyl cellulose, epoxy
resins, acrylonitrile/styrene, polystyrene, polyamide,
polyisobutylene, polyethylene, polymethyl-methacrylate, polyvinyl
chloride/divinylbenzene, divinylbenzene/styrene, and combinations
and mixtures thereof.
[0035] Other sources can be utilized to form electrodes for use in
capacitive deionization units. In one embodiment, electrodes
exemplified are U.S. Pat. No. 6,737,445 to Bell et al. and U.S.
application No. 20030153636 to Dietz et al. are utilized, whereby
these references are incorporated by reference. Further, the
electrodes may be arranged in a flow through fashion, as described
in U.S. Pat. No. 6,462,935 to Shiue et al. and U.S. application No.
20040095706 to Faris et al., whereby these references are
incorporated by reference.
[0036] Additional electrode sources for use in capacitive
deionization units are exemplified in the following U.S. patents
and patent applications, all hereby incorporated by reference: U.S.
Pat. Nos. 5,425,858; 5,636,437; 5,954,937; 5,980,718; 6,309,532;
6,346,187; and 6,761,809. U.S. patent Publication Nos. 2002-0084188
and 2004-0188246.
[0037] Further electrode sources, utilized in flow-through
capacitors by the referenced materials as, for use in capacitive
deionization units are exemplified in the following references, all
hereby incorporated by reference: U.S. Pat. Nos. 5,192,432;
5,415,768; 5,547,581; 5,620,597; 5,748,437; 5,779,891; 6,127,474;
6,325,907; 6,413,409; 6,628,505; 6,709,560; 6,778,378; and
6,781,817. U.S. patent Publication Nos. 2004-0012913 and
2004-0174657. WO 01/66217 and WO 03/009920.
[0038] In one embodiment, the flow rate of feed water treated with
capacitive deionization to make an at least partially softened
water is from about 0.5 liters/min to about 20.0 liters/min, in
another embodiment from about 0.75 liters/min to about 8
liters/min, in yet another embodiment from about 1 liters/minute to
about 5 liters/min, in still another embodiment greater than about
1 liter/minute.
[0039] In one embodiment, the overall surface area of the
electrodes utilized in the capacitive deionization unit is from
about 200 to about 1500 m.sup.2/g; in another embodiment from about
400-1200 m.sup.2/g; in another embodiment from about 500-1000
m.sup.2/g.
[0040] In one embodiment the potential difference or voltage is
from about 0.5 volts to about 10 volts; in another embodiment from
about 0.75 to about 8 volts; in yet another embodiment from about 1
to about 5 volts.
[0041] In one embodiment, the capacitive deionization unit is
capable of self-cleaning. In one self-cleaning embodiment, cleaning
commences when the electrodes exhibit diminished adsorption of the
ionic species from the solution as noted by the decrease in the
resistivity of the outlet water--water processed by the washing
systems of the present invention--and/or a decrease in the level of
hardness reduction. In one embodiment, the decreased performance of
the electrodes is observed by a conductivity meter. One of ordinary
skill in the art would readily be able to determine means of
measuring the decrease in performance of the electrodes of the
present invention. The decreased performance, in one embodiment, is
measured by dividing the conductivity of the "dirty" electrode--an
electrode containing ionic species gathered by operation of the
washing systems--by the conductivity of the "clean"
electrode--electrode before the use of the washing systems, whereby
clean electrode in one embodiment is substantially free of ionic
species--to determine the conductivity fraction. When the
conductivity fraction reaches a predetermined value, a
self-cleaning cycle is initiated. In one embodiment, a
self-cleaning cycle is initiated when the conductivity fraction is
less than about 0.9, in another embodiment, the conductivity
fraction is less than about 0.7, in yet another embodiment, the
conductivity fraction is less than about 0.5, in yet another
embodiment, the conductivity fraction is less than about 0.4, in
yet another embodiment, the conductivity fraction is less than
about 0.3, in yet another embodiment, the conductivity fraction is
less than about 0.2, in yet another embodiment the conductivity
fraction is between about 0.1 and about 0.6, in yet another
embodiment the conductivity fraction is between about 0.2 and
0.4.
[0042] Optionally, the capacitive deionization unit further
comprises a prefilter. Without wishing to be bound by theory, it is
believed that the prefilter is capable of extending the life of the
electrodes, as well as delaying the frequency of the self-cleaning
cycle of the electrodes. It is believed that the prefilter absorbs,
blocks, or otherwise removes neutrally charged species contained in
feed water. Such neutrally charges species are minimally effected
by the electrodes on the capacitive deionization unit and thus are
capable of contaminating the adsorption sites on the electrodes.
The prefilter of the present invention is made from any material
that substantially absorbs, blocks, and/or otherwise removes
neutrally charged species from feed water. Such materials include,
but are not limited to, activated carbon, silica, paper, metallic
mesh filters, membranes, gels, and combinations thereof.
[0043] Nanofiltration
[0044] In another embodiment, the water-softening zone comprises a
feed water filtration device. One type of filtration device is a
nanofiltration device having a cut-off in the range from about 100
to about 1000 Daltons, in one embodiment from about 200 to about
1000 Daltons. The clean water flux of the device, on the other
hand, is in one embodiment at least 3, in one embodiment at least 6
L/m.sup.2h at 100 kP at 25.degree. C. The device in one embodiment
has a magnesium ion rejection of at least 50%, in one embodiment at
least 80% (0.35 wt % MgSO.sub.4, 600 kP, Re=2500, 25.degree.
C.).
[0045] In yet another embodiment, the water-softening zone takes
the form of a cross-flow filtration device having permeate and
retentate outlet ports, the permeate outlet port being in fluid
communication with the washing zone and the retentate outlet port
being in fluid communication with one or more of the effluent
storage, discharge and wash liquor-cleanup and recycle zones.
[0046] In still another embodiment, cross-flow devices are provided
with a feed water input, retentate recirculation, hard-water
effluent bleed and optional recirculation pump. In one embodiment,
the flux ratio of soft-water permeate to hard-water effluent is at
least about 1:1, In another embodiment at least about 3:1, in yet
another embodiment at least about 5:1, and in still another
embodiment at least about 8:1.
[0047] Such filtration devices in one embodiment take the form of a
module comprising a filter housing provided with a membrane
compartment in which is mounted a bundle of capillary or tubular
filtration membranes, the ends of which are encased in membrane
holders and which communicate with one or more inlet ports and one
or more retentate outlet ports. The filter housing is also provided
with one or more openings in the wall of the filter housing and
which communicate with one or more permeate outlet ports. Hot or
cold water from the feed supply enters the filter housing via a
connection into the inlet port and then passes through the
capillary or tubular filtration membranes, the resulting retentate
and permeate being discharged through connections into the
corresponding retentate and permeate outlet ports. Such an
arrangement is referred to herein as an `inside-out`
arrangement.
[0048] Alternatively, the module can be operated in reverse manner
(`outside-in`) wherein the feed water is supplied and the retentate
discharged via openings in the wall of the filter housing
communicating with corresponding inlet and retentate outlet port
connections. In this case permeate is collected within the
filtration membranes and discharged via their open ends and
corresponding permeate outlet port connections.
[0049] The module can also be provided with one or more distributor
pipes placed transverse to the direction of the filtration
membranes with one or more openings into the membrane compartment
in order to reduce the transverse forces on the filtration
membranes, such an arrangement being described in detail in
WO-A-98/20962.
[0050] Exemplary filtration devices or modules include
polyamide/polyethersulfone nanofiltration membranes developed for
inside-out filtration marketed by X-Flow B.V. under the designation
NF50M10.
[0051] Nanofiltration membranes can be prone to degradation or
attack by chlorine in feed water. Accordingly the filtration device
may be used in conjunction with a chlorine removal system such as a
carbon prefilter, an antioxidant or brass in order to extend the
working life of the device.
[0052] In filtration device embodiments, the filtration device in
one embodiment also comprises a pump for recirculating the
retentate stream through the filtration module under elevated
pressure, the pump either being situated in the recirculation loop
with the sole or primary purpose of retentate recirculation or else
being operatively connected to the main discharge pump of the
washing appliance or washing zone.
[0053] Electrodialysis/Electrodeionization
[0054] In yet another embodiment, the water-softening zone
comprises an electrodialysis unit or electrodeionization unit. In
electrodialysis, cation-exchange membranes are alternatively
stacked with anion-exchange membranes and the resulting
compartmentalized array is placed between two oppositely-charged
electrodes. Feed water is fed into the device under low pressure
and circulated between the membranes. On application of direct
current to the electrodes, cations and anions move in opposite
directions towards the cathode and anode respectively and
concentrate in alternate compartments. The at least partially
softened water resulting from the electrodialysis unit is then fed
to the washing zone and the hard water effluent fed to one or more
of the effluent storage, discharge and wash liquor-cleanup and
recycle zones.
[0055] Electrodeionization is in effect a combination of
electrodialysis with ion exchange. In this case a mixture of
cation- and anion-exchange resins are introduced between the
cation- and anion-exchange membranes and all ionic species in the
feed water are trapped within the resin. The at least partially
softened water output is then fed to the washing zone whereupon the
device undergoes an electrochemical regeneration cycle in which the
cation- and anion-exchange resins are regenerated for subsequent
use. The resulting the hard water effluent is then fed to one or
more of the effluent storage, discharge and wash liquor-cleanup and
recycle zones.
[0056] Wash Liquor Cleanup
[0057] Optionally, the washing system comprises a wash liquor
cleanup and recycle zone in fluid communication with the washing
zone for purposes of cleaning and recycling the wash liquor from
the washing zone. Cleaning of the wash liquor can be performed as a
separate batch operation on bulk liquor at an off-line location,
but in one embodiment cleaning is performed on a stream of the wash
liquor within a recycle loop section of the washing system.
Alternatively cleaning can take place within a section or sub-zone
of the washing zone itself. The term `cleaning` refers to a
reduction in the soil content of the wash liquor (either the bulk
liquor or the wash liquor stream as appropriate), soil content
being measured, for example, by means of turbidity. In one
embodiment the turbidity of the recycled wash liquor is less than
about 15 NTU, in one embodiment less than about 5 NTU.
[0058] After cleaning, the liquor is recycled back to the washing
zone where it can be used in the same or a subsequent washing step
or in a post-wash rinsing step. In preferred embodiments of this
type, the wash liquor is recycled to the washing zone during or at
the end of an essentially detergent-free prewash step prior to a
detergent-assisted, in one embodiment a bleach-assisted washing
step. Prewash embodiments of the invention are particularly
valuable herein in the case of bleach-assisted substrate washing
steps from the viewpoint of providing improved bleaching and
cleaning performance. Preferably, the washing system is arranged to
provide continuous or semi-continuous cleanup and recycle of wash
liquor during the same substrate washing step, in other words, the
wash liquor is recycled continuously or in one or more phases of
operation during the washing or prewashing step so as to remove
soil from the washing zone and reduce or minimize soil redeposition
onto the substrate. By `essentially-free` of detergent is meant a
wash liquor containing less than about 0.1% of detergent product by
weight of the wash liquor.
[0059] In certain systems and methods of the invention the wash
liquor cleanup and recycle zone comprises a wash liquor filtration
device which is effective to lower the turbidity of the recycled
wash liquor to less than about 15 NTU, in one embodiment less than
about 5 NTU. The permeate flux delivered by the device, on the
other hand, is in one embodiment at least about 100 L/h, in one
embodiment at least about 500 L/h when operating at a pressure in
the range from about 100 to about 1000 kP (1-10 bar), in one
embodiment from about 100 to about 400 kP (1-4 bar). The surface
area of the membrane is in one embodiment from about 0.01 to about
2 m.sup.2, in one embodiment from about 0.05 to about 1 m.sup.2, in
one embodiment from about 0.25 to about 0.75 m.sup.2.
[0060] In other embodiments herein, the wash liquor cleanup and
recycle zone comprises an ultrafiltration or microfiltration
device. The filtration device in one embodiment has a cut-off in
the range from about 1000 Daltons to about 1 .mu.m, in one
embodiment from about 0.05 .mu.m to about 0.5 .mu.m. The filtration
device in one embodiment comprises one or more tubular membranes,
the lumen size of each membrane being in one embodiment from about
1 to about 10 mm, in one embodiment from about 2 to about 6 mm, and
in one embodiment from about 3 to about 5 mm. The filtration device
in one embodiment has a clean water flux of at least about 1000
L/m.sup.2.h.100 kp (RO water at 25.degree. C.), in one embodiment
at least about 10,000 L/m.sup.2 at 100 kP. The cut-off herein
refers to the nominal pore size rating of the membrane of the
device except that the overall minimum value (1000 Daltons) is
given in terms of molecular weight cut-off. Lumen size refers to
the minimum internal diameter of the membrane.
[0061] In one embodiment, the system of the present invention
includes a wash liquor cleanup and recycle zone that comprises a
cross-flow filtration device. In one embodiment, the cross-flow
filtration device comprises one or more free-standing, asymmetric,
tubular filtration membranes, each tubular membrane having a lumen
size having the dimensions described above. In other embodiments,
the device comprises a series of intercommunicating membrane
subunits, each subunit being in the form of a bundle comprising one
or more, in one embodiment from about 2 to about 20, in one
embodiment from about 5 to about 15 of the tubular filtration
membranes. Where the device comprises a plurality of subunits in
series, the individual subunits can be interconnected by one or
more sections of tubular membrane having a larger lumen size. The
total path length of tubular membrane in the device is in one
embodiment from about 10 to about 250 m, in one embodiment from
about 35 to about 150 m and the pressure drop across the cross-flow
filtration device from its inlet to its outlet is less than about 2
bar, in another embodiment less than about 1 bar, and in another
embodiment from about 0.2 to about 0.5 bar. Furthermore each
tubular membrane in one embodiment has a Reynold's Number of at
least about 2300, in another embodiment at least about 4000 at an
operating pressure in the range from about 100 to about 1000 kP
(1-10 bar), in another embodiment from about 100 to about 400 kP
(14 bar).
[0062] The cross-flow filtration device is provided with wash
liquor input and permeate and retentate outlet ports, the permeate
outlet port being in fluid communication with the washing zone and
the retentate outlet port being in fluid communication with a wash
liquor buffer zone or with the effluent discharge zone.
[0063] In systems employing a wash liquor buffer zone, wash liquor
is fed or drawn from the washing zone to the buffer zone along a
first conduit and is then fed under pressure with the aid of a pump
along a second conduit from the buffer zone to the inlet port of
the cross-flow filtration device. A conventional coarse filter
designed to remove particles of greater than about 20 microns, for
example activated carbon, can also be provided upstream of the
cross-flow filtration device for removal of larger size impurities.
The resulting retentate is then recirculated to the buffer zone
with permeate being returned to the washing zone. A pressure relief
valve can also be provided on the inlet port of the cross-flow
filtration device, excess pressure being relieved by drainage into
the buffer zone or effluent discharge zone. In one embodiment, the
buffer zone is closed to the atmosphere in which case wash liquor
is automatically drawn into the buffer zone in tandem with the
removal of permeate to the washing zone. Alternatively the buffer
zone can be vented to atmosphere and the wash liquor fed under
pressure from the washing zone to the buffer zone. Relief valves
can also be positioned on the retentate outlet and on the inlet and
outlet sides of the buffer zone. A valve, for example a pinch
valve, can also be provided on the permeate outlet port of the
filtration device to enable intermittent clean-sweeping or
back-flushing of the filtration membrane. However, it is a feature
of the systems of the invention that they require minimal
maintenance in the form of back-flushing or defouling
procedures.
[0064] The filtration device in one embodiment takes the form of a
module comprising a filter housing provided with a membrane
compartment in which the tubular filtration membrane or membranes
are mounted, the ends of which are encased in membrane holders and
communicate with the inlet and retentate outlet ports. Where the
device comprises a series of intercommunicating membrane subunits,
each subunit generally comprises a bundle of tubular membranes, a
pair of membrane holders for encasing the ends of the tubular
membranes and an outer sheath provided with one or more openings to
allow discharge of permeate into the membrane compartment of the
filter housing. The individual membrane subunits can
intercommunicate via one or more sections of interconnecting
tubular membrane having a lumen size generally greater than that of
the individual subunits. The terminal subunits of the series, on
the other hand, can communicate with the inlet and retentate outlet
ports via one or more sections of tubular membrane and
corresponding membrane holders set into the membrane housing. The
filter housing is also provided with one or more openings in the
wall of the filter housing communicating with the permeate outlet
port or ports. Wash liquor enters the filter housing via a
connection into the inlet port and then passes through the
filtration membrane or membranes, the resulting retentate and
permeate being discharged through connections into the
corresponding retentate and permeate outlet ports.
[0065] A wide range of membrane materials can be employed herein
for the ultrafiltration or microfiltration device including
polypropylene, polyvinylidene difluoride, cellulose acetate,
cellulose, polypropylene, polyacrylonitrile, polysulfones,
polyarylsulphones, polyethersulphones, polyvinyl alcohol, polyvinyl
chloride, polycarbonate, aliphatic and aromatic polyamides,
polyimides and mixtures thereof. Preferred herein however is an
asymmetric polyethersulphone membrane having a nominal pore size
ratio (inner to outer surface) of about 1:10 and a surface energy
(inner surface) of about 8 dynes/cm.
[0066] Product Dosing
[0067] In one embodiment, the washing systems of the invention
comprise a dosing zone situated intermediate the water-softening
zone and the washing zone. In one embodiment, the dosing zone
comprises means for dosing product (either an active detergent or a
detergent auxiliary such as a finishing agent or fabric enhancer)
into the pre-softened feed water within or on the feed water inlet
to the washing zone and may also comprise product storage means for
bulk detergent and/or detergent auxiliary product. In addition, the
product dispensing zone will generally comprise means enabling
filling, refilling or replacement of the product storage means and
may in addition comprise valves, dispensing orifices or other means
for controlling the dosing rate of the detergent and/or detergent
auxiliary product relative to the soft water flux of the
water-softening zone. In one embodiment, the dispensing and
water-softening zones are serially-connected or comprise an
integral water-softening and product-dispensing unit, i.e. a unit
having separate but interconnected water-softening and
product-dispensing zones, the product-dispensing zone being
downstream of the water-softening zone and comprising means for
dosing product into the feed water on the output side of the
water-softening zone.
[0068] In one embodiment the substrate is contacted with the wash
liquor while simultaneously performing cleanup and recycle of the
wash liquor. In such embodiments, it can be advantageous to perform
cleanup and recycle in one or more phases of operation during the
substrate washing step. For example, in one embodiment, cleanup and
recycle is initiated in the final half of the washing step, for
example, after a completion of about 50%, in one embodiment at
least about 70% or even about 90% of the time for the washing step.
Alternatively cleanup and recycle is initiated only after the
system has reached its optimum washing temperature or after the
wash liquor has reached a threshold turbidity or conductivity value
or a threshold value of soil. For this purpose, the washing system
can be provided with one or more sensors responsive to the
turbidity, conductivity or soil level of the wash liquor and which
acts as a trigger for initiating cleanup and recycle.
[0069] In another preferred embodiment which is useful for the
laundering of fabrics, the wash liquor is recycled to the washing
zone or rinsing zone for use in a post-wash rinsing step. Again
there can also be included a recycle reservoir for storing the
cleaned wash liquor prior to recycling. In one embodiment the
method comprises at least one of or any combination of i) a water
softening step wherein the feed water is softened in the water
softening zone, ii) an optional detergent dispensing step wherein
an active detergent product is dosed in a cleaning-effective amount
into the wash liquor or feed water, iii) a washing step wherein the
soiled substrate is contacted with the softened wash liquor, iv)
the wash liquor cleanup and recycle step, v) a fabric enhancer
dispensing step wherein a fabric enhancer providing a post-wash
fabric care or aesthetic benefit is dosed into the recycled wash
liquor, and vi) a rinsing step wherein the fabrics are contacted
with the resulting rinse liquor. Suitable fabric enhancers include
perfumes and other olfactory agents, textile softening agents,
ironing aids, antibacterial agents, anti-pilling aids, etc.
[0070] In preferred methods of the invention, the washing step is
undertaken at a detergent product wash liquor concentration in the
range from about 0 to about 2% by weight, in one embodiment from
about 0.01% to about 1% by weight, in one embodiment from about
0.01% to about 0.5% by weight, and in one embodiment from about
0.01% to about 0.25% by weight. Typically, however, the detergent
product will be present in a cleaning-effective amount, i.e. an
amount effective to improve the cleaning end-result over and above
the end-result that can be achieved in the absence of detergent.
Accordingly, the detergent product will normally be present in a
level of at least 0.1% by weight of the wash liquor. Suitably the
wash liquor pH during the washing step is in the range from about 5
to about 13, in one embodiment from about 6 to about 12, in one
embodiment from about 7 to about 11. In methods comprising the use
of detergency enzymes such as proteases, cellulases and amylases,
the enzyme concentration during the washing step is in one
embodiment from about 0.0001 to about 100 ppm of active enzyme. A
non-limiting list of enzymes suitable for use herein is disclosed
in, for example, US2002/0155971.
[0071] Sonics
[0072] In another application of the invention, the washing systems
herein additionally comprise means for sonically or ultrasonically
treating the soiled substrate in the washing zone or in a washing
pre-treatment zone. In particular it has been found herein that the
combination of sonic or ultrasonic treatment with wash liquor
cleanup and recycle and water-softening is particularly valuable
for providing improved cleaning of substrates across the range of
detergent usage levels. In one embodiment the means for sonically
or ultrasonically treating the soiled substrate comprises a sonic
or ultrasonic energy generator or a plurality of such generators
wherein the frequency of the generated energy is in the range from
about 1 kHz to about 150 kHz, in one embodiment from about 20 kHz
to about 80 kHz and the power input to the generator is in the
range from about 0.1 W to about 500 W, in one embodiment from about
10 W to about 250 W.
[0073] In one embodiment, the energy generator is adapted for
generating and supplying ultrasonic energy to the soiled substrate
within the washing zone. In such an embodiment, the frequency of
the generated energy is in one embodiment in the range from about
20 kHz to about 150 kHz, in one embodiment from about 20 kHz to
about 80 kHz, and the power input to the generator is in one
embodiment in the range from about 20 W to about 500 W per gallon
of wash liquor (5.28 W to 132.1 W per litre), in one embodiment
from about 25 W to about 250 W per gallon of wash liquor (6.6 W to
66.1 W per litre) in the washing zone. An energy generator suitable
for use in such embodiments comprises an ultrasound transducer and
an electronic power supply. The ultrasound transducer can be either
a PZT (Lead-Zirconate-Titanite) transducer or a magnetostrictive
transducer. Examples of the commercial ultrasound transducers
include Vibra-Cell VCX series from Sonics & Materials Inc, and
Tube Resonator from Telsonic AG. Single or array of several
transducers can be used in the washing system. The transducer(s)
can be mounted at the bottom or on the sidewall surrounding the
washing zone. It can also be submersed directly in the washing
zone. The transducers can also be mounted within the washing
machine drum or tub as described in detail below.
[0074] In a preferred embodiment of this type, the washing system
takes the form of a front-loading washing machine comprising a drum
for accommodating the laundry, the drum having one or more, in one
embodiment two to four, in one embodiment three baffles on the
inner circumferential wall thereof for tumbling the laundry. The
washing machine also comprises one or more sonic or ultrasonic
generators mounted on at least one and in one embodiment on each
baffle of the drum so that sonic or ultrasonic energy is applied to
the laundry as the laundry items are lifted out of the bulk wash
liquor in contact with the corresponding baffle. In another
embodiment of this type, the washing system takes the form of a
top-loading washing machine having a central agitator paddle having
one or more sonic or ultrasonic generators mounted thereon.
[0075] In an alternative embodiment, the energy generator is
adapted for generating and supplying sonic or ultrasonic energy to
the soiled substrate within the washing pre-treatment zone. In such
an embodiment, the frequency of the generated energy is in one
embodiment in the range from about 1 kHz to about 80 kHz, in one
embodiment from about 20 kHz to about 60 kHz, and the power input
to the generator is in one embodiment in the range from about 0.1 W
to about 80 W, in one embodiment from about 1 W to about 40 W. An
energy generator suitable for use in such embodiments comprises one
or more vibrating cleaning transducers adapted to physically
contact one or more surfaces of the soiled substrate. In use, the
soiled substrate is passed under or between the cleaning
transducers, the substrate being simultaneously or previously
wetted with wash liquor. The cleaning transducer can be mounted in
a convenient position outside the washing zone and provided with
means to enable drainage of the wash liquor into the washing
zone.
[0076] The systems and methods of the invention can also include
embodiments that combine the energy generator for the washing zone
and the energy generator for the washing pre-treatment zone with
frequencies and power inputs as described above.
[0077] Electrolysis Zone
[0078] In a further application of the invention, the washing
systems herein additionally comprise an electrolysis zone for
electrolysing the feed water or wash liquor for purposes of
generating electrolytically-activated wash liquor and/or rinse
liquor. In particular it has been found herein that the combination
of electrolysis with wash liquor cleanup and recycle and
water-softening is particularly valuable for providing improved
cleaning of substrates across the range of detergent usage levels.
The electrolysis zone herein in one embodiment comprises
electrolysis means provided with at least a pair of electrodes for
electrolysing the feed water or wash liquor, the electrolysis means
being referred to respectively as feed water electrolysis means and
wash water electrolysis means. Generally the feed water
electrolysis means is disposed intermediate the feed supply and
washing zone, while the wash liquor electrolysis means is disposed
within the washing zone or within the wash liquor recycle zone. A
combination of feed water and wash liquor electrolysis means is
also envisaged herein. Optionally, the electrolysis zone can also
comprise a reservoir (the electrolysis reservoir) for storage of
the resulting electrolysed water, and means for storage and
dispensing of electrolyte or other oxidant-precursor species into
the feed water or wash liquor.
[0079] In terms of function, electrolysis zones suitable for use
herein include both oxidant-generating and pH-generating
electrolysis zones. In oxidant-generating embodiments of the
invention, the feed water or wash liquor comprises in use one or
more oxidant-precursor species and the electrolysis zone comprises
means for generating one or more streams of oxidant or
mixed-oxidant species in the feed water or wash liquor by
electrolysis of the oxidant-precursor species.
[0080] In pH-generating embodiments of the invention, the
electrolysis zone comprises means for generating one or more
streams of acidic and/or alkaline species in the feed water or wash
liquor, said one or more streams being supplied to the washing zone
for use in the substrate washing step or in a subsequent substrate
rinsing step.
[0081] By `electrolytically-activated wash liquor` is meant wash
liquor that has been subjected to electrolysis, e.g. to generate
oxidant, mixed oxidant, acidic or alkaline species, or wash liquor
derived from feed water that has been subjected to electrolysis.
The term `electrolytically-activated rinse liquor` on the other
hand refers to rinse liquor derived from feed water or wash liquor
that has been subjected to electrolysis.
[0082] In one embodiment, the electrolysis unit is utilized in
combination with the capacitive deionization unit to generate
bleaching species capable for use as stain removers and for
sanitization. In such an embodiment, the waste stream from the
capacitive deionization unit is routed to the electrolysis unit.
Without wishing to be bound by theory, it is believed that the
waste stream from the capacitive deionization unit contains a high
level of cationic and/or anionic species. The cationic and/or
anionic species within the waste stream, upon electrolysis, are
converted to various bleaching species including, but not limited
to, hypochlorite, chlorine dioxide, and combinations thereof. It is
believed that the majority of bleaching species are in the base
stream. The bleaching species generated are routed to the washing
zone. Without wishing to be bound by theory, it is believed that
the acid stream, when sent to the washing zone, in the washing zone
acts as an antimicrobial in the washing zone. Further, it is
believed that the base stream, when sent to the washing zone, acts
to raise the pH to improve cleaning. Further the acid stream and/or
base stream could be recombined and still deliver a bleaching
effect in the wash zone or the one or both streams could be sent to
the waste.
[0083] In another embodiment, the acid stream and/or the base
stream from the electrolysis unit is used to clean and/or
regenerate the electrodes and/or other units. In such an
embodiment, the electrolysis unit is used to generate an acid
stream and/or a base stream. Without wishing to be bound by theory,
it is believed that any metal species located on the electrodes
will react when contacted by the acid stream while any neutral
organic species will react when contacted by the base stream. After
contact with the acid and/or the base stream, the neutral metal
species and/or the neutral organic species become soluble. Upon
solublization, the reacted neutral metal species and the neutral
organic species optionally can be expelled as a waste electrode
stream out of the capacitive deionization unit.
[0084] In yet another embodiment, the acid stream and/or the base
stream can be used to clean various units in connection with the
current invention. In one non-limiting example, the acid stream
and/or the base stream is used to clean a cross-filtration unit.
Without wishing to be bound by theory, the acid stream and/or the
base stream is brought into contact with the surface of the
membranes of the cross flow filtration unit. Upon contact, the acid
stream and/or the base stream reacts and/or dissolves species
located on the membrane, thus providing cleaning.
[0085] In one embodiment, an electrolysis brine is added to the
water before electrolysis. Without wishing to be bound by theory,
it is believed that the addition of the electrolysis brine to the
water before electrolysis facilitates in the production of
bleaching species, including HClO.sup.-. In one embodiment, the
electrolysis brine comprises sodium chloride and water. The
percentage by weight of sodium chloride in water for the
electrolysis brine is from about 0.1% to about 35.9%, in another
embodiment from about 1% to about 30%, in another embodiment from
about 4% to about 20%, in another embodiment from about 5% to about
10%. The electrolysis brine is added to the softened water such
that, in the wash zone, a percentage by volume concentration of
electrolysis brine to softened water is from about 0.1% to about to
20%, in another embodiment from about 1% to about 10%, in another
embodiment from about 2% to about 7%, in another embodiment, from
about 3% to about 6%, in another embodiment from about 1% to about
4%.
[0086] Disinfection Zone
[0087] In another application of the invention, the washing systems
herein additionally comprise a wash liquor disinfection zone. In
particular it has been found herein that the combination of wash
liquor disinfection with wash liquor cleanup and recycle and
water-softening is particularly valuable for providing improved
cleaning of substrates across the range of detergent usage
levels.
[0088] The disinfection zone can take a number of different forms.
In a first embodiment, the disinfection zone comprises an
antibacterial agent (which term herein includes both bactericidal
and bacteriostatic agents) and means for delivering the
antibacterial agent to the wash liquor. In one embodiment the
antibacterial agent comprises one or more oxidant or bleaching
species such as ozone, hypochlorous acid or one or more
antibacterial metal ion sources inclusive of silver, copper, zinc,
tin and compounds thereof as well as combinations of said
antibacterial ion sources with inorganic carrier materials. In a
preferred embodiment of this type, the disinfection zone comprises
an electrolytic source of an antibacterial agent such as silver,
copper, zinc or tin ions or of an active oxidant or bleaching
species such as hypochlorous acid. In another embodiment, the
disinfection zone comprises a photocatalyst and/or UV source. In
such embodiments, the photocatalyst and/or UV source can be
associated with an ultrafiltration or microfiltration device for
purposes of cleaning and disinfecting both the filtration device
and the wash liquor.
EXAMPLE
[0089] FIGS. 1-3 are included to provide non-limiting examples of
the methods and devices of the present invention.
[0090] FIG. 1 comprises device 101, feed water 102 and wash zone
103. When wash zone 103 requests cold water 112 or hot water 110,
the pressure drop is detected by hot water pressure sensor 113
and/or cold water pressure sensor 111. Hot water pressure sensor
113 and/or cold water pressure sensor 111 communicates with feed
water valve 114 and/or outlet water valve 116 to open or close. For
hot water treatment, feed water valve 114 and outlet water valve
116 are opened such that hot water 110 flows through device 101.
For cold water treatment, feed water valve 114 and outlet water
valve 116 are opened such that cold water 112 flows through device
101. Combinations of hot water 110 and cold water 110 can be formed
by either opening feed water valve 114 and outlet water valve 116
partially so that hot water 110 and cold water 112 mix within
device 101 or by alternating feed water valve 114 and outlet water
valve 116 to allow hot water 110 and cold water 112 into wash zone
103 in an alternating fashion, thereby mixing hot water 110 and
cold water 112 in wash zone 103. Hot water 110 and/or cold water
112 flows through capacitive deionization unit 120 to form softened
water. Waste electrolyte stream 122 is generated by capacitive
deionization unit 120. Softened water from capacitive deionisation
unit 120 optionally is injected with electrolysis brine 132.
Softened water containing optionally injected electrolysis brine
132 is flowed through electrolysis unit 130 to form electrolyzed
water. Upon flowing through electrolysis unit 130, electrolyzed
water is optionally injected with detergent 140 and/or optional
fabric enhancer 142 and flowed through outlet water valve 116 into
hot stream 115 and/or cold stream 117 and through hot wash zone
inlet 104 and/or cold wash zone inlet 105 into wash zone 103.
[0091] FIG. 2 comprises a device 201, feed water 202 and wash zone
203. When wash zone 203 requests cold water 212 or hot water 210,
the pressure drop is detected by hot water pressure sensor 213
and/or cold water pressure sensor 211. Hot water pressure sensor
213 and/or cold water pressure sensor 211 communicates with feed
water valve 214 and/or outlet water valve 216 to open or close. For
hot water treatment, feed water valve 214 and outlet water valve
216 are opened such that hot water 210 flows through device 201.
For cold water treatment, feed water valve 214 and outlet water
valve 216 are opened such that cold water 212 flows through device
201. Combinations of hot water 210 and cold water 212 can be formed
by either opening feed water valve 214 and outlet water valve 216
partially so that hot water 210 and cold water 212 mix within
device 201 or by alternating feed water valve 214 and outlet water
valve 216 to allow hot water 210 and cold water 212 into wash zone
203 in an alternating fashion, thereby mixing hot water 210 and
cold water 212 in wash zone 203. Hot water 210 and/or cold water
212 flows through capacitive deionization unit 220 to form softened
water. Waste electrolyte stream 222 is generated by capacitive
deionization unit 220. Softened water from the capacitive
deionisation unit 220 optionally is injected with electrolysis
brine 232. Softened water containing optionally injected
electrolysis brine 232 is flowed through electrolysis unit 230 to
optionally form bleach-containing water. Bleach storage valve 233
is capable of directing bleach-containing water from electrolysis
unit 230 to bleach storage tank 234. Bleach-containing water from
bleach storage tank 234 can be pumped back into electrolysis unit
230 utilizing bleach recirculation pump 236 and bleach
recirculation valve 231. Upon flowing through electrolysis
recirculation loop 238, softened water and/or bleach-containing
water is optionally injected with detergent 240 and/or fabric
enhancer 242 and flowed through outlet water valve 216 into hot
stream 215 and/or cold stream 217 and through hot wash zone inlet
204 and/or cold wash zone inlet 205 into wash zone 203.
[0092] FIG. 3 comprises device 301, feed water 302 and wash zone
303. When wash zone 303 requests cold water 312 or hot water 310,
the pressure drop is detected by hot water pressure sensor 313
and/or cold water pressure sensor 311. Hot water pressure sensor
313 and/or cold water pressure sensor 311 communicates with feed
water valve 314 and/or outlet water valve 316 to open or close. For
hot water treatment, feed water valve 314 and outlet water valve
316 are opened such that hot water 310 flows through device 301.
For cold water treatment, feed water valve 314 and outlet water
valve 316 are opened such that cold water 312 flows through device
301. Combinations of hot water 310 and cold water 312 can be formed
by either opening feed water valve 314 and outlet water valve 316
partially so that hot water 310 and cold water 312 mix within
device 301 or by alternating feed water valve 314 and outlet water
valve 316 to allow hot water 310 and cold water 312 into wash zone
303 in an alternating fashion, thereby mixing hot water 310 and
cold water 312 in wash zone 303. Hot water 310 and/or cold water
312 flows through capacitive deionization unit 320 to form softened
water. Waste electrolyte stream 322 is generated by capacitive
deionization unit 320. Softened water from capacitive deionisation
unit 320 optionally is injected with electrolysis brine 332.
Softened water containing optionally injected electrolysis brine
332 is flowed through electrolysis unit 330 to form acid stream 364
containing acidic water and base stream 362 containing alkali
water. Acidic water from acid stream 364 is directed into acid
storage tank 366 or base stream 362 by acid-stream valve 365.
Acidic water from acid storage tank 366 is pumped outside of
electrolysis recirculation loop 336 to either acid-entry valve 363
or capacitive deionization cleaning valve 367 by acid storage pump
368. Upon flowing through electrolysis recirculation loop 336,
softened water containing optionally injected electrolysis brine,
acidic water, and/or alkali water is optionally injected with
detergent 340 and/or fabric enhancer 342, mixed at mixer 350, and
flowed through outlet water valve 316 into hot water 315 and/or
cold stream 317 and through hot wash zone inlet 304 and/or cold
wash zone inlet 305 into wash zone 303.
[0093] All documents cited in the Detailed Description of the
Invention are, are, in relevant part, incorporated herein by
reference; the citation of any document is not to be construed as
an admission that it is prior art with respect to the present
invention.
[0094] While particular embodiments of the present invention have
been illustrated and described, it would be obvious to those
skilled in the art that various other changes and modifications can
be made without departing from the spirit and scope of the
invention. It is therefore intended to cover in the appended claims
all such changes and modifications that are within the scope of
this invention.
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