U.S. patent application number 10/823228 was filed with the patent office on 2005-10-13 for method and apparatus for cleaning objects in an automatic cleaning appliance using an oxidizing agent.
Invention is credited to Brown-West, Boma M., Kaeding, Janice M., Kehl, Dennis, Lindgren, Gary M., Luckman, Joel a., Wright, Tremitchell L..
Application Number | 20050224099 10/823228 |
Document ID | / |
Family ID | 35059322 |
Filed Date | 2005-10-13 |
United States Patent
Application |
20050224099 |
Kind Code |
A1 |
Luckman, Joel a. ; et
al. |
October 13, 2005 |
Method and apparatus for cleaning objects in an automatic cleaning
appliance using an oxidizing agent
Abstract
A method and apparatus for cleaning objects in an automatic
cleaning appliance is provided that includes the steps of
introducing a load of objects into a wash zone of the automatic
cleaning appliance, applying a wash liquor and at least one of
electromagnetic, chemical and mechanical energy to the load of
objects in the wash zone to remove soil from the load of objects,
and subsequently applying an oxidizing agent to the load of objects
through the medium of a fluid applied to the load of objects. The
oxidizing agent may be generated in association with the automatic
cleaning appliance.
Inventors: |
Luckman, Joel a.;
(Stevensville, MI) ; Wright, Tremitchell L.;
(Elkhart, IN) ; Kehl, Dennis; (Benton Harbor,
MI) ; Brown-West, Boma M.; (Stevensville, MI)
; Kaeding, Janice M.; (Lawrence, MI) ; Lindgren,
Gary M.; (Three Oaks, MI) |
Correspondence
Address: |
WHIRLPOOL PATENTS COMPANY-MD 0750
Suite 102
500 Renaissance Drive
St. Joseph
MI
49085
US
|
Family ID: |
35059322 |
Appl. No.: |
10/823228 |
Filed: |
April 13, 2004 |
Current U.S.
Class: |
134/41 |
Current CPC
Class: |
C11D 11/007 20130101;
C23G 3/00 20130101; B08B 3/02 20130101; C11D 3/3947 20130101; C11D
3/386 20130101; C23G 1/06 20130101; B08B 3/044 20130101; B08B 3/08
20130101; B08B 3/10 20130101 |
Class at
Publication: |
134/041 |
International
Class: |
C23G 001/02 |
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A method of cleaning objects in an automatic cleaning appliance,
comprising: introducing a load of objects into a wash zone of said
automatic cleaning appliance; introducing a wash liquor to said
load of objects in said wash zone; applying at least one of
electromagnetic, chemical and mechanical energy to said load of
objects in said wash zone to remove soil from said load of objects;
and subsequently applying an oxidizing agent to said load of
objects, through the medium of a wash liquor applied to said load
of objects.
2. A method according to claim 1, wherein said wash liquor
comprises a water based solution.
3. A method according to claim 2, wherein said wash liquor
comprises enzymes in said solution.
4. A method according to claim 3, wherein said oxidizing agent is
applied to said load of objects after a delay of a predetermined
time following the application of said enzymes to said load of
objects sufficient to allow said enzymes to work properly on said
load of objects.
5. A method according to claim 1, wherein said electromagnetic
energy comprises thermal energy and is applied to said load of
objects by means of a heater being activated for a period of time
to heat said wash liquor, and said oxidizing agent is applied to
said load of objects after said heater is deactivated.
6. A method according to claim 1, wherein said objects are fabric
and said cleaning appliance comprises an automatic washer.
7. A method according to claim 1, wherein said objects are foodware
and said cleaning appliance comprises an automatic dishwasher.
8. A method according to claim 1, wherein said wash zone is
arranged to rotate about a vertical axis.
9. A method according to claim 8, wherein said oxidizing agent is
introduced to said wash zone in a lower region of said wash
zone.
10. A method according to claim 1, wherein said wash zone is
arranged to rotate about a horizontal axis.
11. A method according to claim 1, wherein said automatic cleaning
appliance includes a sump where said wash liquor from said wash
zone collects, said method further comprising the step of pumping
said wash liquor from said sump into said wash zone, wherein said
step of applying said oxidizing agent further comprises introducing
said oxidizing agent into said sump.
12. A method according to claim 1, further comprising an initial
wash cycle during which said at least one of said electromagnetic,
chemical and mechanical energy is applied to said load of objects,
and said oxidizing agent is applied to said load of objects no
sooner than approximately 5 minutes into said initial wash
cycle.
13. A method according to claim 1, wherein a first water based
rinse cycle occurs after said application of at least one of
electromagnetic, chemical and mechanical energy, and wherein said
step of applying said oxidizing agent comprises applying said
oxidizing agent to said load of objects during said first rinse
cycle.
14. A method according to claim 1, wherein a first water based
rinse cycle occurs after said application of at least one of
electromagnetic, chemical and mechanical energy, and wherein said
step of applying said oxidizing agent comprises applying said
oxidizing agent to said load of objects at the beginning of said
first rinse cycle.
15. A method according to claim 1, wherein said oxidizing agent
comprises hydrogen peroxide.
16. A method according to claim 15, wherein said hydrogen peroxide
is provided in said fluid medium at a concentration in the range of
10 to 10000 parts per million.
17. A method according to claim 15, wherein said hydrogen peroxide
is generated in association with said automatic cleaning
appliance.
18. A method according to claim 15, wherein said hydrogen peroxide
is activated in association with said automatic cleaning appliance
through contact with chemically-modified surfaces to form hydroxyl
radicals.
19. A method according to claim 15, wherein said automatic cleaning
appliance is provided with a water supply line for providing water
to be used in said wash liquor and said hydrogen peroxide is
generated in said automatic cleaning appliance through electrolysis
of water introduced through said water supply line.
20. A method according to claim 1, wherein said oxidizing agent is
generated in association with said automatic cleaning
appliance.
21. A method according to claim 1, wherein said oxidizing agent is
generated in said automatic cleaning appliance.
22. A method according to claim 20, wherein said automatic cleaning
appliance is provided with a water supply line, providing water to
be used in said wash liquor and said oxidizing agent is generated
in said automatic cleaning appliance through electrolysis of water
introduced through said water supply line.
23. A method of cleaning objects in an automatic cleaning
appliance, comprising: introducing a load of objects into a wash
zone of said automatic cleaning appliance; applying a wash liquor
and at least one of electromagnetic, chemical and mechanical energy
to said load of objects in said wash zone to remove soil from said
load of objects; generating an oxidizing agent via a chemical
generating device arranged in association with said automatic
cleaning appliance; and subsequently applying said oxidizing agent
to said load of objects, through the medium of a fluid applied to
said load of objects.
24. A method of cleaning objects according to claim 23, wherein
said chemical generating device is located within a cabinet of said
automatic cleaning appliance.
25. A method of cleaning objects according to claim 23, wherein
heat is generated in the process of generating said oxidizing
agent, and said heat is applied to load of objects in said wash
zone as at least a part of said electromagnetic energy.
26. A method of cleaning objects in an automatic cleaning
appliance, comprising: introducing a load of objects into a wash
zone of said automatic cleaning appliance; electrochemically
decomposing a chemical composition into resultants via an
electrochemical cell device arranged in association with said
automatic cleaning appliance; reacting at least one of said
resultants to form an oxidizing agent, applying a wash liquor and
at least one of electromagnetic, chemical and mechanical energy to
said load of objects in said wash zone to remove soil from said
load of objects; subsequently applying said oxidizing agent to said
load of objects, through the medium of a fluid applied to said load
of objects.
27. A method of cleaning objects according to claim 26, wherein
said electrochemical cell device is located within a cabinet of
said automatic cleaning appliance.
28. A cleaning appliance for cleaning a load of objects comprising:
a wash chamber defining a wash zone for accepting said load of
objects; a dispenser for applying wash liquor to said wash chamber;
a sump for collecting wash liquor that has been applied to said
wash chamber; and a chemical generating device for generating an
oxidizing agent for dispensing into said wash liquor.
29. A cleaning apparatus according to claim 28 wherein said objects
are fabric and said cleaning apparatus is an automatic washer.
30. A cleaning apparatus according to claim 29 wherein further
comprising agitation means for moving said fabric within said wash
chamber.
31. A cleaning apparatus according to claim 28 wherein said objects
are foodware and said automatic cleaning apparatus is an automatic
dishwasher.
32. A cleaning apparatus of claim 28 further comprising means for
applying at least one of electromagnetic, chemical and mechanical
energy to said load of objects in said wash zone to remove soil
from said load of objects
33. A cleaning apparatus according to claim 32, wherein said means
for applying energy comprises a heater adapted to heat said wash
liquor, said oxidizing agent being applied to said load of objects
after said heater is deactivated.
34. A cleaning apparatus according to claim 28, wherein said
oxidizing agent is introduced to said wash chamber in a lower
region of said wash zone.
35. A cleaning apparatus according to claim 28, wherein said
chemical generating device creates said oxidizing agent from wash
liquor in said sump.
36. A cleaning apparatus according to claim 28, wherein said
oxidizing agent comprises hydrogen peroxide.
37. A cleaning apparatus according to claim 36, wherein said
hydrogen peroxide is introduced in said wash liquor at a
concentration in the range of 10 to 10000 parts per million.
38. A cleaning apparatus according to claim 36, wherein said
hydrogen peroxide is activated in said chemical generating device
through contact with chemically modified surfaces to form hydroxyl
radicals.
39. A cleaning apparatus according to claim 36, further comprising
a water supply line for providing water to be used in said wash
liquor, and further wherein said chemical generating device
generates said hydrogen peroxide through electrolysis of water
introduced through said water supply line.
40. A cleaning apparatus according to claim 28, further comprising
a water supply line for providing water to be used in said wash
liquor, and further wherein said chemical generating device
generates said hydrogen peroxide through electrolysis of water
introduced through said water supply line.
41. An automatic cleaning appliance comprising: a wash zone
arranged to receive a load of objects to be cleaned and a wash
liquor to be applied to the load of objects in said wash zone; a
water supply line communicating with said wash zone; a hydrogen
peroxide generator arranged to receive a supply of water from said
water supply line; a conduit leading from said hydrogen peroxide
generator to said wash zone.
42. An automatic cleaning appliance comprising: a wash zone
arranged to receive a load of objects to be cleaned and a wash
liquor to be applied to the load of objects in said wash zone; a
chemical generating device arranged in association with said
appliance to generate an oxidizing agent; and a conduit leading
from said chemical generating device to said wash zone.
Description
BACKGROUND OF THE INVENTION
[0001] Cleaning a soiled load of objects in automatic cleaning
appliances generally involves the use of chemical energy (such as
detergent), mechanical energy (such as through agitation of the
object load in a wash liquor or the manner of dispensing the wash
liquor against the object load, such as spraying) and/or thermal
energy (such as through an elevated temperature of the wash
liquor). Different combinations of these energy inputs provide
various levels of soil removal from the load. Depending on the type
of objects in the load, there may be attendant damage, such as when
the load comprises fabric, resulting in the generation of lint or
the fading of various colors of the fabric, etc. Other types of
objects could be subject to chemical etching or other types of
damage.
[0002] Numerous types of chemical wash additives are known, such as
detergents which include surfactants and emulsifiers, as well as
enzymes, all used to dissolve, loosen and/or remove various soils
and stains. Additional chemical additives in the form of bleaches,
such as chlorine-based bleaches have been used to effect soil
removal, particularly on white fabrics, since such bleaches are
effective to remove colors from fabrics as well. With a fashion
trend changing from white fabric to vibrant colors, the use of
chlorine-based bleaches has become problematic.
[0003] There has been a development of color-safe bleaches, such as
oxygen-based bleaches, also referred to as oxidizing agents. One
such oxygen bleach that has been receiving consideration is
hydrogen peroxide. One of the potential drawbacks associated with
oxygen bleaches is that they have an adverse effect on some of the
components found within many detergent formulations. For example,
the hydrogen peroxide can deactivate enzymes, thus decreasing the
washing performance of automatic cleaning appliances.
[0004] The application of additives to the wash liquor places a
thermal burden on the wash liquor, in those situations where the
wash liquor is heated above ambient temperature to provide thermal
energy to the soil removal process. Typically the additives are
maintained at ambient temperature, so additional energy is required
to elevate the additives to the temperature of the wash liquor, or
else the temperature of the wash liquor is detrimentally lowered
upon the addition of the additives.
[0005] It would be an improvement in the art if a process were
provided for utilizing an oxidizing agent in an automatic cleaning
appliance that did not detract from the effectiveness of the
chemistry of the wash liquor and which did not pose a thermal load
on the wash liquor while the wash liquor is being applied to the
objects in the elevated temperature enhanced wash process.
SUMMARY OF THE INVENTION
[0006] A method and apparatus for cleaning a soiled load of objects
in an automatic cleaning appliance is provided which overcomes the
problems noted above and permits the use of an oxidizing agent in
an automatic cleaning appliance so that it does not detract from
the effectiveness of the chemistry of the wash liquor and which
does not pose a thermal load on the wash liquor while the wash
liquor is being applied to the objects in an elevated temperature
enhanced wash process.
[0007] In an embodiment of the invention, the method includes
introducing a load of objects into a wash zone of the automatic
cleaning appliance, applying a wash liquor and at least one of
electromagnetic, chemical and mechanical energy to the load of
objects in the wash zone to remove soil from the load of objects,
and subsequently applying an oxidizing agent to the load of
objects, through the medium of a fluid applied to the load of
objects. By not applying the oxidizing agent simultaneously with
the introduction of the wash liquor and energy to the object load,
the problems described above are avoided.
[0008] In an embodiment of the invention wherein the wash liquor
comprises a water based solution and there are enzymes in the
solution, the oxidizing agent may be applied to the load of objects
after a delay of a predetermined time following the application of
the enzymes to the load of objects sufficient to allow the enzymes
to work properly on the load of objects.
[0009] In an embodiment of the invention wherein thermal energy is
applied to the load of objects by means of a heater being activated
for a period of time to heat the wash liquor, the oxidizing agent
may be applied to the load of objects after the heater is
deactivated in order to avoid posing a thermal load while the heat
from the heater is being used to enhance the wash process.
[0010] The method of the present invention may be practiced in an
automatic cleaning appliance wherein the wash zone is arranged to
rotate about a vertical axis or where the wash liquor is dispensed
from a rotating spray arm. In such a machine, the oxidizing agent
may be introduced to the wash zone in a lower region of the wash
zone in order to assure a proper mixing of the oxidizing agent with
the wash liquor before it is introduced to the object load. An
additional embodiment includes adding the oxidizing agent to the
top of the wash bath after a majority of the working fluid has
entered the bath. Optionally, the oxidizing agent may be introduced
via a recirculation pump that takes fluid from the sump and
re-introduces the flow into the top of the tub. Finally, the
oxidizing agent may be added simultaneously to the lower region of
the wash zone as well as the top half of the wash zone through a
flow splitter or diverter valve. This option provides the
aforementioned mixing advantage as well as providing direct contact
of the oxidizing agent to the soiled objects.
[0011] The method of the present invention may also be practiced in
an automatic cleaning appliance wherein the wash zone is arranged
to rotate about a horizontal axis or, again, where the wash liquor
is dispensed from a rotating spray arm. In such a machine, the
oxidizing agent may be introduced into a sump where the wash liquor
collects, and from where the wash liquor is pumped into the wash
zone.
[0012] In an embodiment of t,he present invention, including an
initial wash cycle during which at least one of electromagnetic,
chemical and mechanical energy is applied to the load of objects,
the oxidizing agent may be applied to the load of objects no sooner
than approximately midway through the initial wash cycle.
[0013] In an embodiment of the present invention, wherein a first
water based rinse cycle occurs after the application of at least
one of electromagnetic, chemical and mechanical energy, the
oxidizing agent may be applied to the load of objects during the
first rinse cycle.
[0014] In an embodiment of the present invention, the oxidizing
agent comprises hydrogen peroxide. In such an embodiment, the
hydrogen peroxide may be provided in the fluid medium at a
concentration in the range of 10 to 10000 parts per million, more
preferably less than 2500 parts per million, and most preferably,
less than 1000 parts per million.
[0015] In an embodiment of the present invention utilizing hydrogen
peroxide, the hydrogen peroxide may be generated in the automatic
cleaning appliance. Additional activation routes include
introducing the oxidizing agent in a high pH environment (greater
than 8) or activating through an electromagnetic source like
ultraviolet or visible light with the addition of a catalyst.
[0016] In an embodiment of the present invention utilizing hydrogen
peroxide, the hydrogen peroxide may be activated in the automatic
cleaning appliance through contact with chemically modified
surfaces to form hydroxyl radicals.
[0017] In an embodiment of the present invention, the automatic
cleaning appliance may be provided with a water supply line for
providing water to be used in the wash liquor and the hydrogen
peroxide is generated in the automatic cleaning appliance through
electrolysis of water introduced through the water supply line.
[0018] In an embodiment of the present invention, a method of
cleaning objects in an automatic cleaning appliance is provided
including the steps of introducing a load of objects into a wash
zone of the automatic cleaning appliance, electrochemically
decomposing a chemical composition into resultants via an
electrochemical cell device arranged in the automatic cleaning
appliance, applying a wash liquor and at least one of
electromagnetic, chemical and mechanical energy to the load of
objects in the wash zone to remove soil from the load of objects,
and subsequently applying at least one of the resultants to the
load of objects, through the medium of a fluid applied to the load
of objects.
[0019] The present invention also contemplates an automatic
cleaning appliance in which the invention can be realized.
[0020] In one embodiment, such an automatic cleaning appliance
could include a wash chamber defining a wash zone for accepting a
load of objects, a dispenser for applying wash liquor to the wash
chamber, a sump for collecting wash liquor that has been applied to
the wash chamber, and a chemical generating device for generating
an oxidizing agent in the wash liquor.
[0021] In another embodiment, such an automatic cleaning appliance
could include a wash zone arranged to receive a load of objects to
be cleaned and a wash liquor to be applied to the load of objects,
a water supply line communicating with said wash zone, a hydrogen
peroxide generator arranged to receive a supply of water from the
water supply line and a conduit leading from the hydrogen peroxide
generator to the wash zone.
[0022] The objects cleaned in the automatic cleaning appliance
could include porous fabric and textile objects, such as clothing,
linens and similar materials, and could include non-porous
ceramics, metals, plastics and similar materials made into dishes
and other food preparation and servicing objects and utensils, as
well as many different types of raw and manufactured
components.
BRIEF DESCRIPTION OF THE DRAWING
[0023] FIG. 1 illustrates a flow chart of various steps of a method
embodying the principles of the present invention.
[0024] FIG. 2 schematically illustrates an automatic cleaning
appliance embodying the principles of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0025] The present invention is directed to a method for cleaning
objects in an automatic wash system or cleaning appliance using an
oxidizing agent, as well as for an apparatus to effect such
cleaning.
[0026] Although a variety of oxidizing agents may be used in the
method of the invention, one such agent is hydrogen peroxide, and
this particular agent is discussed in detail below. However, it
should be understood that the present invention is not limited to
this particular oxidizing agent. Some additional chemical
compositions include ozone, percarbonate, perborate, singlet
oxygen, peroxy acids (RCO.sub.3H), hypochlorite, chlorine and
chlorine dioxide, metal oxyacids such as all forms of chromium (VI)
and permanganate ion (KMnO.sub.4), nitric acid, nitrous acid,
sodium peroxide, halogens, but more specifically Br.sub.2 and
Cl.sub.2 and compounds containing Cl.sup.- and Br.sup.- and mild
oxidizing agents such as Ag.sup.+ and Cu.sup.2+.
[0027] FIG. 1 illustrates an embodiment of the invention, which
includes, in step 20, introducing a load of objects into a wash
zone of the automatic cleaning appliance. In step 22, a wash liquor
and at least one of electromagnetic, chemical and mechanical energy
are automatically applied to the load of objects in the wash zone
by the automatic cleaning appliance to remove soil from the load of
objects. The wash liquor may be either an aqueous (water) based
solution or a non-aqueous based solution, such as disclosed in U.S.
Pat. Nos. 6,451,066 and 6,045,588 which are incorporated herein by
reference. The electromagnetic energy may be in the form of
infrared (thermal), ultraviolet or microwave to heat or disinfect
the object load, soil or wash liquor, or may be from other parts of
the electromagnetic spectrum. The chemical energy may be supplied
via various detergent and other additives in liquid or gaseous
form, which may also be applied in concentrated form, as disclosed
in U.S. Pat. No. 4,784,666 which is incorporated herein by
reference. Alternative techniques for introducing the chemical
energy including the oxidizing agent include foams, mists or
vapors.
[0028] The mechanical energy may be supplied by agitating the
object load in the wash zone by various means such as agitators,
impellers, vanes, baffles and rotations or oscillations of the wash
zone, or by spinning the object load at a high speed and applying a
fluid wash liquor to the objects which is driven through or around
the objects by the spinning action. Ultrasonic energy may be
applied to the object load or the wash liquor to induce a
mechanical agitation or vibration to assist in loosening or
removing soil from the objects. The wash liquor may be applied to
the object load in the form of sprays or jets to impart mechanical
energy into the object load. Also, solid additives may be
introduced to the object load to dispense chemicals or to increase
mechanical energy being applied to the object load. Several
exemplary arrangements are disclosed in U.S. Pat. Nos. 5,191,667,
5,191,669, 5,219,370, 5,271,251, 5,345,637, 5,460,018, 5,507,053,
6,591,638, all of which are incorporated herein by reference.
[0029] In step 24, which is to occur subsequent to step 22, an
oxidizing agent is applied to the load of objects, which may be
through the medium of a fluid applied to the load of objects.
[0030] In this embodiment, the purpose for applying the oxidizing
agent subsequent to the application of wash liquor and some type of
energy, is to avoid the negative effects of the oxidizing agent on
the various chemistry of the wash liquor if a chemical energy is
used, such as in the form of a detergent with an enzyme additive,
or to avoid the thermal load the oxidizing agent would place on the
wash liquor if a thermal energy is used in association with the
wash liquor, such as via heating the wash liquor to make it more
effective in removing soils from the object load.
[0031] In an embodiment of the invention wherein the wash liquor
introduced in step 22 comprises a water based solution and there
are enzymes in the solution, the oxidizing agent may be applied in
step 24 to the load of objects after a delay of a predetermined
time following the application of the enzymes to the load of
objects sufficient to allow the enzymes to work properly on the
load of objects. For example, in a washing method which includes an
initial wash cycle during which at least one of electromagnetic,
chemical and mechanical energy is applied to the load of objects as
a step 22, the oxidizing agent may be applied to the load of
objects in step 24 no sooner than some fixed time period, such as 5
minutes, or no sooner than approximately midway through the initial
wash cycle. Alternatively, in a washing method which includes a
first water based rinse cycle occurring after the step of applying
at least one of electromagnetic, chemical and mechanical energy in
step 22, the oxidizing agent may be applied to the load of objects
as step 24 during the first rinse cycle.
[0032] In a wash method wherein the electromagnetic energy
comprises thermal energy, the thermal energy may be applied to the
load of objects by means of a heater being activated for a period
of time to heat the wash liquor, such as prior to or during step
22, the oxidizing agent may be applied to the load of objects in
step 24 after the heater is deactivated in order to avoid posing a
thermal load while the heat from the heater is being used to
enhance the wash process. Such a heater is intended to include all
manners of heaters including those using electrical resistance,
combustions of fuels such as natural gas or liquid petroleum,
microwave heaters, etc.
[0033] In an embodiment of the present invention, the oxidizing
agent introduced in step 24 may comprise hydrogen peroxide. In such
an embodiment, the hydrogen peroxide may be provided in the fluid
medium at a concentration in the range of 10 to 10000 parts per
million, more preferably less than 2500 parts per million and most
preferably less than 1000 parts per million. A suitable medium may
be water, but other fluid mediums may be used as well. Some of
these additional fluids are non-aqueous liquid solvents such as
fluorinated solvents, perchloroethylene, siloxane-based solvents,
hydrocarbon-based solvents, ionic liquids, liquid CO.sub.2 and
combinations thereof. More specifically, the fluorinated solvents
are selected from the group comprising methoxynonafluorobutane,
ethoxynonafluorobutane and decafluoropentane. The siloxane-based
solvents can be selected from decamethylcyclopentasiloxane,
dodecamethylpentasiloxane, decamethyltetrasiloxane and combinations
thereof. Finally, gases, partially compressed gases and compressed
gases including air and CO.sub.2 may be an acceptable medium as
well.
[0034] In some embodiments of the invention, the oxidizing agent
may be applied to the load of objects in step 24 automatically, and
therefore a supply of oxidizing agent may be stored in a reservoir
in association with the automatic cleaning appliance, with an
appropriate dispensing mechanism provided to meter a desired amount
of oxidizing agent onto the object load. For example, a storage
reservoir may be located within the cleaning appliance cabinet, or
may be located in proximity to the cleaning appliance cabinet, and
connected thereto with a conduit. In some embodiments, the
oxidizing agent may be generated in or near the automatic cleaning
appliance, such as in optional step 26 (shown interposed between
steps 22 and 24 with dashed lines) in FIG. 1. For example, if the
oxidizing agent is hydrogen peroxide, this agent may be generated
via an electrochemical cell associated with the automatic cleaning
appliance, so that a continuous supply of the oxidizing agent may
be made available automatically, without requiring the user to
periodically fill a reservoir with a supply of oxidizing agent.
Specifically, the automatic cleaning appliance may be provided with
a water supply line for providing water to be used in the wash
liquor and the hydrogen peroxide may be electrochemically generated
in the automatic cleaning appliance via the decomposition of the
water introduced through the water supply line.
[0035] Such an arrangement is not limited to the generation of
hydrogen peroxide. In an embodiment of the present invention, there
may be included the step of generating an oxidizing agent via a
chemical generator device arranged in the automatic cleaning
appliance, applying a wash liquor and at least one of
electromagnetic, chemical and mechanical energy to the load of
objects in the wash zone to remove soil from the load of objects,
and subsequently applying the oxidizing agent to the load of
objects, through the medium of a fluid applied to the load of
objects. While hydrogen peroxide is specifically described as one
such oxidizing agent, formed in a reaction of hydrogen and oxygen,
the resultants of an electrolysis of water, other oxidizing agents
could similarly be formed. The chemical generator may be an
electrochemical cell that decomposes a chemical composition, such
as water, into resultants, such as hydrogen and oxygen, and then
reacts at least one of the resultants to form an oxidizing agent,
such as hydrogen peroxide. During the decomposition, the process
can be combined with an oxygen-enrichment from air to further
facilitate reactants. Other potential resultants could be ozone,
hydroxyl radicals and metal containing hydroxides, depending on the
purity of the inlet water.
[0036] In those embodiments of the invention utilizing hydrogen
peroxide, the hydrogen peroxide may optionally be activated in the
automatic cleaning appliance through contact with
chemically-modified surfaces, such as in step 28 (shown interposed
between steps 26 and 24 with dashed and dotted lines)of FIG. 1, to
form hydroxyl radicals before the oxidizing agent is applied to the
object load such as transition metal oxides, transition metal
oxides doped with other elements including nitrogen and carbon,
ferrous sulfate and ferrous sulfite.
[0037] A preferred embodiment utilizes titanium dioxide to activate
the oxidizing agent and more-preferably nitrogen-doped or
carbon-doped titanium dioxide.
[0038] Methods of producing chemically-modified surfaces include
coating, particle impregnation, sputtering, vapor phase deposition,
electroplating, plasma deposition, graphing and
nano-technologies.
[0039] These chemically-modified surfaces may be used to delay the
activation of the oxidizing agent in the process. Other methods
that may be used to delay or control activating the oxidizing agent
include are centrifugal switch activation, alternate paths in the
machine such as re-circulation.
[0040] The method of the present invention may be practiced in an
automatic cleaning appliance 30 such as shown schematically in FIG.
2. Such cleaning appliance 30 could be an automatic clothes washer,
an automatic dishwasher, or other types of automatic washers. In
one such cleaning appliance 30, a wash zone 32 may be arranged to
rotate about a vertical axis. In such a cleaning appliance 30, the
oxidizing agent 36 may be introduced to the wash zone 32 in a lower
region 38 of the wash zone in order to assure a proper mixing of
the oxidizing agent with the wash liquor 40 before the oxidizing
agent is introduced to the object load.
[0041] The method of the present invention may also be practiced in
an automatic cleaning appliance 30 wherein the wash zone 32 is
arranged to rotate about a horizontal axis. In such a cleaning
appliance 30, the oxidizing agent 34 may be introduced into a sump
44 where the wash liquor 40 collects, and from where the wash
liquor is pumped into the wash zone 32.
[0042] The cleaning appliance 30 could also include features such
as rotating spray arms, fixed or moving jet outlets, and other
known mechanisms for providing mechanical energy by means of the
introduction or recycling of the wash liquor against the objects
being cleaned.
[0043] As illustrated in FIG. 2, the chemical generator device 48
associated with the automatic cleaning appliance 30 is provided
which provides the generation of desired chemistries directly at or
in association with the cleaning appliance. In some embodiments, a
continuous supply of the elements necessary to generate the desired
chemistries can be connected to the device 48 so that the user need
not periodically add chemistries to the device 48 or the cleaning
appliance 30. In some embodiments, as described below, the
generated chemistries are dispensed automatically to the cleaning
appliance 30 avoiding the need for the user of the appliance to
manually dispense the chemistries into the cleaning appliance.
[0044] The chemical generator device 48 is arranged in association
with the cleaning appliance 30 which has the cleaning zone 32 where
objects are cleaned. The chemical generator device 48 may be
located within an outer cabinet 49 of the cleaning appliance, or
may be located outside of the cabinet in a generally close
proximity to the cleaning appliance 30. The chemical generator
device 48 includes an inlet 51 to allow the introduction of at
least one chemical composition. The chemical composition may be
introduced through the inlet 5 1, such as by a user pouring or
otherwise dispensing a discrete quantity of the chemical
composition through the inlet 5 1, or a supply conduit 46 may be
attached to the inlet 51 such that the chemical composition may be
directed to the inlet through the conduit from a source of supply
which may be a reservoir of a finite volume, or may be from a
source of a relatively continuous supply. For example, if the
chemical composition is water, the conduit 46 may be connected to a
water conduit located in the building where the appliance is
located, thereby providing a relatively continuous supply of
water.
[0045] The chemical generator device 48 also includes an operative
area 53 where a desired chemical composition is generated by
utilizing the at least one chemical composition. An outlet 55 is
provided at the chemical generator device 48 which is arranged to
communicate with the cleaning zone 32 of the cleaning appliance 30.
The outlet 55 may lead directly to the cleaning zone 32, or a
separate conduit 50 may be provided between the outlet 55 and the
cleaning zone 32. In the embodiments where the chemical generator
device is located outside of the cabinet 49 of the cleaning
appliance 30, such a conduit 50 is generally required.
[0046] In some embodiments, the chemical generator device 48 also
includes a dispensing apparatus 57 arranged to dispense the
generated chemical composition to the cleaning zone 32 from the
operative area 53 through the outlet 55. In some embodiments, the
generated chemical composition may be dispensed through the outlet
via gravity, in other embodiments the generated chemical
composition may be dispensed due to a pressure associated with the
chemical composition being introduced through the inlet 51, or due
to a pressure developed during the generation of the generated
chemical composition. In other embodiments, the generated chemical
composition may be dispensed through the use of a pump. In an
embodiment of the invention, the dispensing apparatus 57 is
arranged to automatically dispense the generated chemical
composition to the cleaning zone 32 during a cleaning operation of
the cleaning appliance 30.
[0047] In most embodiments of the present invention a pump is used
to move fluid between conduits, reservoirs, etc. These pumps may be
positive displacement, kinetic or open screw mechanical pumps.
Pumping is not limited to mechanical means and other types of pumps
that be utilized are piezo-electric, electrohydrodynamic, thermal
bubble, magnetohydrodynamic and electroosmotic.
[0048] It is another aspect of the invention to provide a control
system 58. The control system 58 operates the dispensing apparatus
57 to deliver the oxidizing agent to the wash liquor to maximize
performance by using sensors 59. Some types of sensors that may be
preferred include pressure, pH, oxidation reduction potential,
turbidity and conductivity. For example, hydrogen peroxide may be
added to the wash liquor when the turbidity of the wash liquor
suggests that the presence of particulate soils is low, thereby
increasing the effectiveness of the oxidizing agent. Additionally,
when the pH environment is optimal (greater than 8), then the
oxidizing agent may be added to the system facilitating the
production of hydroxyl radicals.
[0049] Where the cleaning appliance 30 uses an aqueous based wash
liquor and therefore has a connection to a source of water; the
water can be used as the initial chemical composition. In such
embodiments, a fluid conditioning device 60 may be arranged in the
water inlet line 46, which may include a filter mechanism or a
chemical treating mechanism, such as a water softening mechanism.
There are different types of filtering mechanisms that may be
effective. For example, a metal, paper or coarse filter may be
implemented at the inlet of the system. This filter will minimize
particulate fouling of the electrochemical cell as well as increase
the effectiveness of the oxidizing agent. This filter may be
provided with a self-cleaning mechanism. Additionally, the inlet
water or water directed to the electrochemical cell may pass
through a fluid conditioning device such as a water softening
mechanism. The purpose of this mechanism will be to reduce the
contamination concentration of the water to less than 1000 parts
per million of a calcium carbonate equivalent, more preferably less
than 500 parts per million and most preferably less than 100 parts
per million. As a result, the performance of the system will be
enhanced.
[0050] In an embodiment of the invention, the chemical generating
device 48 further includes a storage space 61 arranged to receive a
supply of material, such as a salt composition or a catalyst in
solid form to be dissolved by fluid in the chemical generating
device 48, or a fluid material to be dispensed into the chemical
generating device during the generating process.
[0051] In an embodiment of the invention, the cleaning appliance 30
further includes a lockout mechanism 63 for an access door 65 used
in loading objects into the wash zone 32. An activating apparatus
67 is arranged as a part of the control 58 for the lockout
mechanism. The activating apparatus 67 includes a sensor 71
arranged to detect a concentration level of the predetermined
chemicals in the wash zone 32, and upon detection of a level in
excess of a predetermined level, the activation apparatus 67 will
operate the lockout mechanism 63 via line 73 to prevent the door 65
from being opened.
[0052] The automatic cleaning appliance could include the water
supply line 46 communicating with the wash zone 32. A chemical
generator device 48, such as a hydrogen peroxide generator, may be
arranged to receive a supply of water from the water supply line
46. The conduit 50 would lead from the chemical generator device 48
to the wash zone 32 to supply the oxidizing agent to the object
load. Heat generated by the chemical generator device 48, such as
through a transformation of the electrical power supplied to the
chemical generator device, or heat given off during the generation
of the chemical composition, may be utilized as all or a part of
the electromagnetic, in this case thermal, energy applied to the
load of objects in step 22.
[0053] In a preferred embodiment, the chemical system will utilize
an electrolyte to increase the rate of reaction. Sodium chloride,
NaCl, is a useful electrolyte and can be used to make certain
bleaches. Potassium or sodium hydroxide are potential electrolytes.
In the presence of water and electricity, NaOH and KOH produce
hydrogen and oxygen which then in the presence of a catalyst can be
used to make some bleaching compounds. Persulfates and peroxy salts
are potential electrolytes. After an anodic reaction, persulfates
and peroxy salts are in a mixture with hydrogen peroxide and other
oxidizing agents. The hydrogen peroxide and oxidizing agents can be
extracted from solution through steam distillation, contact with an
ion exchange resin, contact with an adsorptive polymer or
combinations thereof. In a preferred embodiment, an anodic reaction
produces hydrogen peroxide. The hydrogen peroxide is then extracted
from the solution during the drying phase of an automatic cleaning
appliance. The heat during the drying step can be used as a steam
distillation technique and the hydrogen peroxide can be extracted
and stored for future uses. Sodium carbonate, Na.sub.2CO.sub.3, can
be used as an electrolyte and the resulting solutions could be
potentially used to manipulate the pH of the wash liquor for the
automatic cleaning appliance. In a preferred embodiment, carbonic
acid is produced through the reaction and is subsequently used to
fight food stains.
[0054] Electrodes for the chemical generating device can be coated
with a variety of species. They can be coated with platinum,
palladium, iridium or combinations thereof catalyst, coated
surfaces. In addition, the surface can be zinc, tin or copper
treated as well. Moreover, electrodes can take a variety of shapes:
plate form, mesh, rod form, tubular form, comb form and punching
metal.
[0055] Not all electrodes in the process participate in the
chemical reaction. In an embodiment of the invention, supporting
electrodes help with the conductivity but don't play a supporting
role in the reaction.
[0056] The chemical generating device can be used for
electrosynthesis. Types of chemicals that can produced by such a
technique are: acetoin, acetylenedicarboxylic acid, adipoin
dimethyl acetal, adiponitrile, 4-aminomethylpyridine,
anthraquinone, azobenzene, S-carbomethoxymethylecy- steine,
L-cysteine, ethanol, hexafluoropropyleneoxide, perfluorinated
hydrocarbons, polysilanes, salicylic aldehyde, succinic acid,
ethylene glycol, propylene oxides, and sorbitol.
[0057] The chemical generating device as described above can be
combined with, integrated with, placed in series or parallel with,
before or after one or multiple chemical reactors. These reactor
include but are not limited to bubble reactors, liquid dispersion
reactors, tubular reactors, falling film reactors, trickle bed
reactors, flooded fixed bed reactors, suspended catalyst bed
reactors, or slurry reactors.
[0058] As is apparent from the foregoing specification, the
invention is susceptible of being embodied with various alterations
and modifications which may differ particularly from those that
have been described in the preceding specification and description.
It should be understood that we wish to embody within the scope of
the patent warranted hereon all such modifications as reasonably
and properly come within the scope of our contribution to the
art.
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