U.S. patent application number 12/114448 was filed with the patent office on 2008-11-06 for water treatment system and downstream cleaning methods.
This patent application is currently assigned to ECOLAB INC.. Invention is credited to Kristen A. Mills, Lee J. Monsrud, Keith E. Olson, Kim R. Smith.
Application Number | 20080274939 12/114448 |
Document ID | / |
Family ID | 39939966 |
Filed Date | 2008-11-06 |
United States Patent
Application |
20080274939 |
Kind Code |
A1 |
Monsrud; Lee J. ; et
al. |
November 6, 2008 |
WATER TREATMENT SYSTEM AND DOWNSTREAM CLEANING METHODS
Abstract
The present invention provides methods for treating an aqueous
system comprising contacting the aqueous system with a composition
comprising a conversion agent. The methods of the present invention
reduce the solubilized water hardness and/or reduce or inhibit
scale formation in an aqueous system. Further, the methods of the
present invention impact the chemistries needed in downstream
cleaning processes employing water treated in accordance with the
methods of the present invention.
Inventors: |
Monsrud; Lee J.; (Inver
Grove Heights, MN) ; Olson; Keith E.; (Apple Valley,
MN) ; Smith; Kim R.; (Woodbury, MN) ; Mills;
Kristen A.; (Hopkins, MN) |
Correspondence
Address: |
ECOLAB INC.
MAIL STOP ESC-F7, 655 LONE OAK DRIVE
EAGAN
MN
55121
US
|
Assignee: |
ECOLAB INC.
St. Paul
MN
|
Family ID: |
39939966 |
Appl. No.: |
12/114448 |
Filed: |
May 2, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60927575 |
May 4, 2007 |
|
|
|
Current U.S.
Class: |
510/405 ;
134/109; 134/56D; 210/287; 210/723; 68/12.13 |
Current CPC
Class: |
C23F 11/08 20130101;
C23F 11/124 20130101; C11D 3/046 20130101; C02F 5/02 20130101; C11D
11/0023 20130101; C23G 1/20 20130101; C11D 3/10 20130101; C02F 5/06
20130101; C02F 2303/22 20130101; C23F 11/18 20130101; C02F 2303/14
20130101; C11D 7/10 20130101; C23G 1/22 20130101; C11D 3/044
20130101 |
Class at
Publication: |
510/405 ;
210/723; 210/287; 134/56.D; 134/109; 68/12.13 |
International
Class: |
C11D 11/00 20060101
C11D011/00; C02F 1/52 20060101 C02F001/52; B01D 27/02 20060101
B01D027/02; B08B 3/04 20060101 B08B003/04; D06F 39/00 20060101
D06F039/00 |
Claims
1. A method for reducing solubilized water hardness in a water
source, said method comprising: (a) contacting the water source
having a pH of between about 6 and about 9 with a composition
comprising a solid conversion agent, wherein the conversion agent
causes calcium hardness ions in the water source to substantially
precipitate in a non-calcite crystalline form that does not need to
be removed from the water source, such that the solubilized water
hardness is substantially reduced.
2. The method of claim 1, wherein the conversion agent is selected
from the group consisting of metal oxides, metal hydroxides, and
combinations thereof.
3. The method of claim 2, wherein the conversion agent is selected
from the group consisting of magnesium oxide, aluminum oxide,
titanium oxide, and combinations thereof.
4. The method of claim 2, wherein the conversion agent is selected
from the group consisting of magnesium hydroxide, aluminum
hydroxide, titanium hydroxide, and combinations thereof.
5. The method of claim 1, wherein the non-calcite crystalline form
is aragonite.
6. The method of claim 1, wherein the composition further comprises
aragonite.
7. The method of claim 6, wherein the composition comprises about 1
wt % to about 50 wt % of aragonite.
8. The method of claim 1, wherein the conversion agent is insoluble
in water.
9. The method of claim 1, wherein the solubilized water hardness is
reduced by about 15% or greater.
10. The method of claim 1, wherein the step of contacting the water
with the conversion agent comprises running the water over the
solid source of the conversion agent.
11. The method of claim 1, wherein the solid conversion agent is
contained in a column.
12. The method of claim 11, wherein the column is agitated by a
method selected from the group consisting of the flow of water
through the column, by fluidization, mechanical agitation, high
flow backwash, recirculation, and combinations thereof.
13. The method of claim 1, wherein the temperature of the water
source prior to contact with the conversion agent is between about
130.degree. F. and about 185.degree. F.
14. The method of claim 1, wherein the solubilized calcium ion
water hardness is reduced.
15. A method of using a treated water source to clean an article
said method comprising: (a) treating a water source with a
composition comprising a conversion agent, wherein the conversion
agent causes calcium hardness ions in the water source to
substantially precipitate in a non-calcite crystalline form that
does not need to be removed from the water source, such that the
solubilized hardness of the water is substantially reduced; (b)
forming a use solution with the treated water and a detergent; and
(c) contacting the article with the use solution such that the
article is cleaned.
16. The method of claim 15, wherein the conversion agent is
selected from the group consisting of metal oxides, metal
hydroxides and combinations thereof.
17. The method of claim 16, wherein the metal oxide is selected
from the group consisting of magnesium oxide, aluminum oxide,
titanium oxide, and mixtures thereof.
18. The method of claim 16, wherein the metal hydroxide is selected
from the group consisting of magnesium hydroxide, aluminum
hydroxide, titanium hydroxide, and mixtures thereof.
19. The method of claim 16, wherein the composition further
comprises aragonite.
20. The method of claim 15, wherein the water source has a neutral
pH prior to treatment.
21. The method of claim 15, wherein the water hardness decreases by
about 15% or greater after treatment.
22. The method of claim 15, wherein the method further comprises
the step of rinsing the article after it has been washed.
23. The method of claim 22, wherein the article is rinsed using
treated water.
24. The method of claim 22, wherein the article is rinsed using
untreated water.
25. The method of claim 15, wherein the amount of calcium hardness
ions in the treated water source is lower than the amount of
calcium hardness ions in the water source prior to the treatment
step.
26. The method of claim 15, wherein the method further comprises
applying a rinse aid to the article after it has been washed.
27. The method of claim 15, wherein the detergent is substantially
free of a chelant or sequestrant.
28. The method of claim 15, wherein the detergent comprises an
insoluble magnesium compound, an alkali metal carbonate, and
water.
29. An apparatus for treating a water source for use in an
automatic warewashing machine comprising: (a) an inlet for
providing the water source to a treatment reservoir; (b) a
treatment reservoir comprising a conversion agent; (c) an outlet
for providing treated water from the reservoir; and (d) a treated
water delivery line for providing the treated water to the
automatic warewashing machine.
30. The apparatus of claim 29, wherein the conversion agent in the
treatment reservoir is a solid particle.
31. The apparatus of claim 30, wherein the solid conversion agent
is selected from the group of metal oxides, metal hydroxides, and
mixtures thereof.
32. The apparatus of claim 31, wherein the metal oxide is selected
from the group consisting of magnesium oxide, aluminum oxide,
titanium oxide, and mixtures thereof.
33. The apparatus of claim 31, wherein the metal hydroxide is
selected from the group consisting of magnesium hydroxide, aluminum
hydroxide, titanium hydroxide, and mixtures thereof.
34. The apparatus of claim 30, wherein the solid conversion agent
is an agitated bed in the treatment reservoir.
35. The apparatus of claim 34, wherein the bed of conversion agent
is agitated by a method selected from the group consisting of the
flow of water through the column, fluidization, mechanical
agitation, high flow backwash, recirculation, and combinations
thereof.
36. The apparatus of claim 29, wherein the treatment reservoir
comprises a portable, removable cartridge.
37. The apparatus of claim 29, wherein there is no filter between
the outlet and the treated water delivery line.
38. A system for use in a cleaning process, said system comprising:
(a) providing a water source to an apparatus for treating the water
source said apparatus comprising: (i) an inlet for providing the
water source to a treatment reservoir; (ii) a treatment reservoir
comprising a conversion agent; (iii) an outlet for providing
treated water from the reservoir; and (iv) a treated water delivery
line for providing the treated water to the automatic washing
machine; and (b) providing treated water to an automatic washing
machine from the treated water delivery line of the apparatus; and
(c) combining the treated water with a detersive composition to
provide a use composition.
39. The system of claim 38, wherein the automatic washing machine
is selected from the group consisting of an automatic ware washing
machine, vehicle washing system, instrument washer, clean in place
system, food processing cleaning system, bottle washer, and an
automatic laundry washing machine.
40. The system of claim 38, wherein the detersive composition
comprises a cleaning composition, a rinse agent composition or a
drying agent composition.
41. The system of claim 38, wherein the detersive agent is
substantially free of a chelant, builder, threshold agent,
sequestrant or combination thereof.
42. The system of claim 38, wherein there is no filter between the
outlet and the treated water delivery line.
43. A method for reducing scale formation in an aqueous system
comprising contacting the aqueous system with a composition
consisting essentially of a solid conversion agent, wherein the
conversion agent causes calcium hardness ions in the water source
to substantially precipitate in a non-calcite crystalline form that
does not need to be removed from the water source, such that scale
formation in the aqueous system is reduced.
44. The method of claim 43, wherein the conversion agent is
selected from the group consisting of metal oxides, metal
hydroxides and combinations thereof.
45. The method of claim 44, wherein the metal oxide is selected
from the group consisting of magnesium oxide, aluminum oxide,
titanium oxide, and mixtures thereof.
46. The method of claim 44, wherein the metal hydroxide is selected
from the group consisting of magnesium hydroxide, aluminum
hydroxide, titanium hydroxide, and mixtures thereof.
47. The method of claim 44, wherein the composition further
comprises aragonite.
Description
RELATED APPLICATIONS
[0001] This application claims priority and is related to U.S.
Provisional Application Ser. No. 60/927,575 filed on May 4, 2007
and entitled "Compositions Containing Magnesium Salts and Methods
of Using." The entire contents of this patent application are
hereby expressly incorporated herein by reference including,
without limitation, the specification, claims, and abstract, as
well as any figures, tables, or drawings thereof.
[0002] This application is also related to: U.S. patent application
Ser. No. ______, entitled "Cleaning Compositions with Water
Insoluble Conversion Agents and Methods of Making and Using Them"
(Attorney Docket No. 2454USU1); U.S. patent application Ser. No.
______, entitled, "Composition For In Situ Manufacture Of Insoluble
Hydroxide When Cleaning Hard Surfaces And For Use In Automatic
Warewashing Machines, And Methods For Manufacturing And Using"
(Attorney Docket No. 2437USU1); U.S. patent application Ser. No.
______, entitled "Water Soluble Magnesium Compounds as Cleaning
Agents and Methods of Using Them" (Attorney Docket No. 2372USU1);
U.S. patent application Ser. No. ______, entitled "Cleaning
Compositions Containing Water Soluble Magnesium Compounds and
Methods of Using Them" (Attorney Docket No. 2488USU1);U.S. patent
application Ser. No. ______, entitled "MG++ Chemistry and Method
for Fouling Inhibition in Heat Processing of Liquid Foods and
Industrial Processes" (Attorney Docket No. 2400USU1); U.S. patent
application Ser. No. ______, entitled "Compositions Including
Hardness Ion and Gluconate and Methods Employing Them to Reduce
Corrosion and Etch" (Attorney Docket No. 163.2365USU1); U.S. patent
application Ser. No. ______, entitled "Compositions Including
Hardness Ion and Silicate and Methods Employing Them to Reduce
Corrosion and Etch" (Attorney Docket No. 163.2487USU1); U.S. patent
application Ser. No. ______, entitled "Compositions Including
Hardness Ion and Threshold Agent and Methods Employing Them to
Reduce Corrosion and Etch" (Attorney Docket No. 163.2406USU1); and
U.S. patent application Ser. No. ______, entitled "Warewashing
Compositions for Use in Automatic Dishwashing Machines and Method
for Using" (Attorney Docket No. 2378USU1), all commonly assigned to
Ecolab, Inc., are filed on the same date as this application being
May 2, 2008 and are all incorporated herein by reference for all
purposes.
FIELD OF THE INVENTION
[0003] The present invention relates to methods for treating an
aqueous system, i.e., a water source or stream. In particular,
methods for reducing solubilized water hardness using various
conversion agents are provided. Methods for inhibiting or reducing
scale formation are also provided. The present invention also
relates to methods of employing treated water, for example, in
cleaning processes.
BACKGROUND
[0004] The level of hardness in water can have a deleterious effect
in many systems. For example, when hard water alone, or in
conjunction with cleaning compositions, contacts a surface, it can
cause precipitation of hard water scale on the contacted surface.
In general, hard water refers to water having a total level of
calcium and magnesium ions in excess of about 100 ppm expressed in
units of ppm calcium carbonate. Often, the molar ratio of calcium
to magnesium in hard water is about 2:1 or about 3:1. Although most
locations have hard water, water hardness tends to vary from one
location to another.
[0005] Water hardness has been addressed in a number of ways. One
method currently used to soften water is via ion exchange, e.g., by
adding sodium to the water to exchange the calcium and magnesium
ions in the water with sodium associated with a resin bed in a
water softening unit. The calcium and magnesium adhere to a resin
in the softener. When the resin becomes saturated it is necessary
to regenerate it using large amounts of sodium chloride dissolved
in water. The sodium displaces the calcium and magnesium, which is
flushed out in a briny solution along with the chloride from the
added sodium chloride. When water softeners regenerate they produce
a waste stream that contains significant amounts of chloride,
creating a burden on the system, e.g., sewer system, in which they
are disposed of, including a multitude of downstream water re-use
applications like potable water usages and agriculture.
[0006] Hard water is also known to reduce the efficacy of
detergents. One method for counteracting this includes adding
chelating agents or sequestrants into detersive compositions that
are intended to be mixed with hard water in an amount sufficient to
handle the hardness. However, in many instances the water hardness
exceeds the chelating capacity of the composition. As a result,
free calcium ions may be available to attack active components of
the composition, to cause corrosion or precipitation, or to cause
other deleterious effects, such as poor cleaning effectiveness or
lime scale build up.
SUMMARY
[0007] In some aspects, the present invention provides a method for
reducing solubilized water hardness in a water source. The method
comprises contacting the water source having a pH of between about
6 and about 9 with a composition comprising a solid conversion
agent. The conversion agent causes calcium hardness ions in the
water source to substantially precipitate in a non-calcite
crystalline form that does not need to be removed from the water
source, such that the solubilized water hardness is substantially
reduced.
[0008] In some embodiments, the conversion agent is selected from
the group consisting of metal oxides, metal hydroxides, and
combinations thereof. In other embodiments, the conversion agent is
selected from the group consisting of magnesium oxide, aluminum
oxide, titanium oxide, and combinations thereof. In still yet other
embodiments, the conversion agent is selected from the group
consisting of magnesium hydroxide, aluminum hydroxide, titanium
hydroxide, and combinations thereof. In other embodiments, the
conversion agent comprises magnesium oxide.
[0009] In some embodiments, the non-calcite crystalline form is
aragonite. In other embodiments, the composition further comprises
aragonite. In some embodiments, the composition comprises about 1
wt % to about 50 wt % of aragonite. In still yet other embodiments,
the conversion agent is insoluble in water. In some embodiments,
the solubilized water hardness is reduced by about 15% or
greater.
[0010] In some embodiments of the method of the present invention,
the step of contacting the water with the conversion agent
comprises running the water over the solid source of the conversion
agent.
[0011] In other embodiments, the solid conversion agent is
contained in a column. The column is agitated by a method selected
from the group consisting of the flow of water through the column,
by fluidization, mechanical agitation, high flow backwash,
recirculation, and combinations thereof, in some embodiments. In
still yet other embodiments, the temperature of the water source
prior to contact with the conversion agent is between about
130.degree. F. and about 185.degree. F. In some embodiments, the
solubilized calcium ion water hardness is reduced.
[0012] In some aspects, the present invention provides a method of
using a treated water source to clean an article. The method
comprises treating a water source with a composition comprising a
conversion agent, wherein the conversion agent causes calcium
hardness ions in the water source to substantially precipitate in a
non-calcite crystalline form that does not need to be removed from
the water source, such that the solubilized hardness of the water
is substantially reduced. A use solution is then formed with the
treated water and a detergent. The article is then contacted with
the use solution, such that the article is cleaned.
[0013] In some embodiments, the method further comprises the step
of rinsing the article after it has been washed. In some
embodiments, the article is rinsed using treated water. In other
embodiments, the article is rinsed using untreated water.
[0014] In some embodiments, the method further comprises applying a
rinse aid to the article after it has been washed. In still yet
other embodiments, the detergent used is substantially free of a
chelant or sequestrant. In other embodiments, the detergent
comprises an insoluble magnesium compound, an alkali metal
carbonate, and water.
[0015] In some aspects, the present invention provides an apparatus
for treating a water source for use in an automatic warewashing
machine. The apparatus comprises: an inlet for providing the water
source to a treatment reservoir; a treatment reservoir comprising a
conversion agent; an outlet for providing treated water from the
reservoir; and a treated water delivery line for providing the
treated water to the automatic warewashing machine.
[0016] In some embodiments, the conversion agent in the treatment
reservoir is a solid particle. In other embodiments, the solid
conversion agent is selected from the group of metal oxides, metal
hydroxides, and mixtures thereof. In still yet other embodiments,
the metal oxide is selected from the group consisting of magnesium
oxide, aluminum oxide, titanium oxide, and mixtures thereof. In
other embodiments, the metal hydroxide is selected from the group
consisting of magnesium hydroxide, aluminum hydroxide, titanium
hydroxide, and mixtures thereof.
[0017] In still yet other embodiments, the solid conversion agent
is an agitated bed in the treatment reservoir. In some embodiments,
the bed of conversion agent is agitated by a method selected from
the group consisting of the flow of water through the column,
fluidization, mechanical agitation, high flow backwash,
recirculation, and combinations thereof.
[0018] In some embodiments, the treatment reservoir comprises a
portable, removable cartridge. In other embodiments, there is no
filter between the outlet and the treated water delivery line.
[0019] In some aspects, the present invention provides a system for
use in a cleaning process. The system comprises providing a water
source to an apparatus for treating the water source. The apparatus
comprises: an inlet for providing the water source to a treatment
reservoir; a treatment reservoir comprising a conversion agent; an
outlet for providing treated water from the reservoir; and a
treated water delivery line for providing the treated water to the
automatic washing machine. The treated water is provided to an
automatic washing machine from the treated water delivery line of
the apparatus. The treated water is combined with a detersive
composition to provide a use composition.
[0020] In some embodiments, the automatic washing machine is
selected from the group consisting of an automatic ware washing
machine, vehicle washing system, instrument washer, clean in place
system, food processing cleaning system, bottle washer, and an
automatic laundry washing machine. In other embodiments, the
detersive composition comprises a cleaning composition, a rinse
agent composition or a drying agent composition. In some
embodiments, the detersive agent is substantially free of a
chelant, builder, threshold agent, sequestrant or combination
thereof. In still yet other embodiments, there is no filter between
the outlet and the treated water delivery line.
[0021] In some aspects, the present invention provides a method for
reducing scale formation in an aqueous system comprising contacting
the aqueous system with a composition comprising a solid conversion
agent, wherein the conversion agent causes calcium hardness ions in
the water source to substantially precipitate in a non-calcite
crystalline form that does not need to be removed from the water
source, such that scale formation in the aqueous system is
reduced.
[0022] These and other embodiments will be apparent to these of
skill in the art and others in view of the following detailed
description. It should be understood, however, that this summary
and the detailed description illustrate only some examples, and are
not intended to be limiting to the invention as claimed.
BRIEF DESCRIPTION OF DRAWINGS
[0023] FIG. 1 is a schematic view of an apparatus for use in
treating water according to the methods of the present
invention.
[0024] FIG. 2 is a photograph of glasses treated with varying
ratios of magnesium oxide to calcite according to the methods of
the present invention.
[0025] FIG. 3 is a photograph of glasses rinsed with either treated
or untreated water as described in Example 1(c).
[0026] FIG. 4 is a photograph of glasses washed with either: a
chelant free detergent and treated water; or a conventional
detergent and untreated water, as described in Example 1(d).
[0027] FIG. 5 is a photograph of glasses washed with either: a
chelant free detergent treated water, and a rinse aid; or a
conventional detergent, untreated water, and a rinse aid, as
described in Example 1(d).
[0028] FIG. 6 is a photograph of soiled glasses washed with either:
a chelant free detergent and treated water; or a conventional
detergent and untreated water, as described in Example 1(d).
[0029] FIG. 7 is a graphical depiction of the effect of various
conversion agents of the present invention on solubilized water
hardness.
[0030] FIG. 8 is a graphical depiction of the percent soil removal
on various soils and textiles of either: a chelant free detergent
and treated water; or a conventional detergent and untreated water,
as described in Example 3.
[0031] FIG. 9 is a graphical depiction of the percent ash left on
wash cloths washed with either treated or untreated water as
described in Example 3.
[0032] FIG. 10 is a graphical depiction of the amount of calcium
(ppm) left on wash cloths washed with either treated or untreated
water as described in Example 3.
[0033] FIG. 11 is a photograph of glasses contacted with either
treated or untreated water at different temperatures as described
in Example 4.
[0034] FIG. 12 is a graphical depiction of the amount of Total
Dissolved Solids (ppm), and SiO.sub.3 in untreated and treated
water used in a vehicle washing facility.
DETAILED DESCRIPTION
[0035] The present invention relates to methods for treating water,
such that the solubilized water hardness is reduced. In some
embodiments, the solubilized calcium portion of water hardness is
precipitated or reduced. In some aspects, a conversion agent, e.g.,
a metal oxide or hydroxide or a polymorph of calcium carbonate, is
used to treat the water. In some embodiments, a solid source of an
insoluble or slightly soluble conversion agent is used to treat the
water. The water treated in accordance with the methods of the
present invention has many beneficial effects, including, but not
limited to, reduction of scale and soiling in areas where hard
water can cause soiling, protecting equipment, e.g., industrial
equipment, from scale build up, increased cleaning efficacy when
used with conventional detersive compositions, and reducing the
need for specific chemistries, e.g., those containing threshold
agents, chelating agents, or sequestrants, or phosphorous, in
downstream cleaning processes.
[0036] So that the invention may be more readily understood certain
terms are first defined.
[0037] As used herein, the terms "chelating agent" and
"sequestrant" refer to a compound that forms a complex (soluble or
not) with water hardness ions (from the wash water, soil and
substrates being washed) in a specific molar ratio. Chelating
agents that can form a water soluble complex include sodium
tripolyphosphate, EDTA, DTPA, NTA, citrate, and the like.
Sequestrants that can form an insoluble complex include sodium
triphosphate, zeolite A, and the like. As used herein, the terms
"chelating agent" and "sequestrant" are synonymous.
[0038] As used herein, the term "free of chelating agent" or
"substantially free of chelating agent" refers to a composition,
mixture, or ingredients that does not contain a chelating agent or
sequestrant or to which only a limited amount of a chelating agent
or sequestrant has been added. Should a chelating agent or
sequestrant be present, the amount of a chelating agent or
sequestrant shall be less than about 7 wt %. In some embodiments,
such an amount of a chelating agent or sequestrant is less than
about 2 wt-%. In other embodiments, such an amount of a chelating
agent or sequestrant is less then about 0.5 wt-%. In still yet
other embodiments, such an amount of a chelating agent or
sequestrant is less than about 0.1 wt-%.
[0039] As used herein, the term "lacking an effective amount of
chelating agent" refers to a composition, mixture, or ingredients
that contains too little chelating agent or sequestrant to
measurably affect the hardness of water.
[0040] As used herein, the term "conversion agent" refers to a
species that causes solubilized calcium in water to substantially
precipitate from solution as calcium carbonate in a form which is
thought to be the thermodynamically unfavorable crystal form
aragonite rather than as the thermodynamically favorable crystal
form calcite. Aragonite is a fragile crystal which doesn't bind
well to surfaces and doesn't form hard water scale while calcite is
a more robust crystal which binds tightly to surfaces, forming a
hard water scale that's not seen with aragonite.
[0041] As used herein, the term "solubilized water hardness" refers
to hardness minerals dissolved in ionic form in an aqueous system
or source, i.e., Ca.sup.++ and Mg.sup.++. Solubilized water
hardness does not refer to hardness ions when they are in a
precipitated state, i.e., when the solubility limit of the various
compounds of calcium and magnesium in water is exceeded and those
compounds precipitate as various salts such as, for example,
calcium carbonate and magnesium carbonate.
[0042] As used herein, the term "water soluble" refers to a
compound that can be dissolved in water at a concentration of more
than 1 wt-%.
[0043] As used herein, the terms "slightly soluble" or "slightly
water soluble" refer to a compound that can be dissolved in water
only to a concentration of 0.1 to 1.0 wt-%.
[0044] As used herein, the term "water insoluble" refers to a
compound that can be dissolved in water only to a concentration of
less than 0.1 wt-%. For example, magnesium oxide is considered to
be insoluble as it has a water solubility (wt %) of about 0.00062
in cold water, and about 0.00860 in hot water. Other insoluble
compounds for use with the methods of the present invention
include, for example: magnesium hydroxide with a water solubility
of 0.00090 in cold water and 0.00400 in hot water; aragonite with a
water solubility of 0.00153 in cold water and 0.00190 in hot water;
and calcite with a water solubility of 0.00140 in cold water and
0.00180 in hot water.
[0045] As used herein, the term "threshold agent" refers to a
compound that inhibits crystallization of water hardness ions from
solution, but that need not form a specific complex with the water
hardness ion. This distinguishes a threshold agent from a chelating
agent or sequestrant. Threshold agents include a polyacrylate, a
polymethacrylate, an olefin/maleic copolymer, and the like.
[0046] As used herein, the term "free of threshold agent" or
"substantially free of threshold agent" refers to a composition,
mixture, or ingredient that does not contain a threshold agent or
to which only a limited amount of a threshold agent has been added.
Should a threshold agent be present, the amount of a threshold
agent shall be less than about 7 wt %. In some embodiments, such an
amount of a threshold agent is less than about 2 wt-%. In other
embodiments, such an amount of a threshold agent is less then about
0.5 wt-%. In still yet other embodiments, such an amount of a
threshold agent is less than about 0.1 wt-%.
[0047] As used herein, the term "antiredeposition agent" refers to
a compound that helps keep a soil composition suspended in water
instead of redepositing onto the object being cleaned.
[0048] As used herein, the term "phosphate-free" or "substantially
phosphate-free" refers to a composition, mixture, or ingredient
that does not contain a phosphate or phosphate-containing compound
or to which a phosphate or phosphate-containing compound has not
been added. Should a phosphate or phosphate-containing compound be
present through contamination of a phosphate-free composition,
mixture, or ingredients, the amount of phosphate shall be less than
about 1.0 wt %. In some embodiments, the amount of phosphate is
less than about 0.5 wt %. In other embodiments, the amount of
phosphate is less then about 0.1 wt %. In still yet other
embodiments, the amount of phosphate is less than about 0.01 wt
%.
[0049] As used herein, the term "phosphorus-free" or "substantially
phosphorus-free" refers to a composition, mixture, or ingredient
that does not contain phosphorus or a phosphorus-containing
compound or to which phosphorus or a phosphorus-containing compound
has not been added. Should phosphorus or a phosphorus-containing
compound be present through contamination of a phosphorus-free
composition, mixture, or ingredients, the amount of phosphorus
shall be less than about 1.0 wt %. In some embodiments, the amount
of phosphorous is less than about 0.5 wt %. In other embodiments,
the amount of phosphorus is less than about 0.1 wt %. In still yet
other embodiments, the amount of phosphorus is less than about 0.01
wt %.
[0050] "Cleaning" means to perform or aid in soil removal,
bleaching, microbial population reduction, or combination
thereof.
[0051] As used herein, the term "ware" refers to items such as
eating and cooking utensils and other hard surfaces such as
showers, sinks, toilets, bathtubs, countertops, windows, mirrors,
transportation vehicles, and floors. As used herein, the term
"warewashing" refers to washing, cleaning, or rinsing ware.
[0052] As used herein, the term "hard surface" includes showers,
sinks, toilets, bathtubs, countertops, windows, mirrors,
transportation vehicles, floors, and the like.
[0053] As used herein, the phrase "health care surface" refers to a
surface of an instrument, a device, a cart, a cage, furniture, a
structure, a building, or the like that is employed as part of a
health care activity. Examples of health care surfaces include
surfaces of medical or dental instruments, of medical or dental
devices, of autoclaves and sterilizers, of electronic apparatus
employed for monitoring patient health, and of floors, walls, or
fixtures of structures in which health care occurs. Health care
surfaces are found in hospital, surgical, infirmity, birthing,
mortuary, and clinical diagnosis rooms. These surfaces can be those
typified as "hard surfaces" (such as walls, floors, bed-pans,
etc.,), or fabric surfaces, e.g., knit, woven, and non-woven
surfaces (such as surgical garments, draperies, bed linens,
bandages, etc.,), or patient-care equipment (such as respirators,
diagnostic equipment, shunts, body scopes, wheel chairs, beds,
etc.,), or surgical and diagnostic equipment. Health care surfaces
include articles and surfaces employed in animal health care.
[0054] As used herein, the term "instrument" refers to the various
medical or dental instruments or devices that can benefit from
cleaning using water treated according to the methods of the
present invention.
[0055] As used herein, the phrases "medical instrument," "dental
instrument," "medical device," "dental device," "medical
equipment," or "dental equipment" refer to instruments, devices,
tools, appliances, apparatus, and equipment used in medicine or
dentistry. Such instruments, devices, and equipment can be cold
sterilized, soaked or washed and then heat sterilized, or otherwise
benefit from cleaning using water treated according to the present
invention. These various instruments, devices and equipment
include, but are not limited to: diagnostic instruments, trays,
pans, holders, racks, forceps, scissors, shears, saws (e.g. bone
saws and their blades), hemostats, knives, chisels, rongeurs,
files, nippers, drills, drill bits, rasps, burrs, spreaders,
breakers, elevators, clamps, needle holders, carriers, clips,
hooks, gouges, curettes, retractors, straightener, punches,
extractors, scoops, keratomes, spatulas, expressors, trocars,
dilators, cages, glassware, tubing, catheters, cannulas, plugs,
stents, scopes (e.g., endoscopes, stethoscopes, and arthoscopes)
and related equipment, and the like, or combinations thereof.
[0056] As used herein, "weight percent (wt-%)," "percent by
weight," "% by weight," and the like are synonyms that refer to the
concentration of a substance as the weight of that substance
divided by the total weight of the composition and multiplied by
100.
[0057] As used herein, the term "about" modifying the quantity of
an ingredient in the compositions of the invention or employed in
the methods of the invention refers to variation in the numerical
quantity that can occur, for example, through typical measuring and
liquid handling procedures used for making concentrates or use
solutions in the real world; through inadvertent error in these
procedures; through differences in the manufacture, source, or
purity of the ingredients employed to make the compositions or
carry out the methods; and the like. The term about also
encompasses amounts that differ due to different equilibrium
conditions for a composition resulting from a particular initial
mixture. Whether or not modified by the term "about," the claims
include equivalents to the quantities.
Compositions and Methods of Use
[0058] In some aspects, the present invention provides methods for
treating water, comprising reducing the solubilized water hardness.
In some embodiments, the solubilized calcium portion of water
hardness is reduced. In some embodiments, the water is contacted
with a composition comprising a conversion agent. In other aspects,
the present invention provides methods for inhibiting or reducing
scale formation in an aqueous system comprising contacting the
aqueous system with a composition comprising a conversion agent.
The conversion agent may be in any form, e.g., solid, particle,
liquid, powder, nanoparticle, slurry, suitable for use with the
methods of the present invention. In some embodiments, a solid
source of a conversion agent is used.
[0059] Without wishing to be bound by any particular theory, it is
thought that the conversion agents for use with the methods of the
present invention cause solubilized calcium water hardness ions in
water to substantially precipitate via an interfacial reaction from
solution as calcium carbonate in the thermodynamically unfavorable
crystal form aragonite rather than as the thermodynamically
favorable crystal form calcite. Aragonite is a fragile crystal
which doesn't bind well to surfaces and doesn't form hard water
scale while calcite is a more robust crystal which binds tightly to
surfaces, forming a hard water scale that's not seen with
aragonite. Thus, contacting water with a conversion agent of the
present invention reduces the solubilized water hardness of the
treated water, and leads to a reduction in scale formation on a
surface in contact with the treated water. The aragonite crystals
can also act as seed crystals for further reduction of solubilized
calcium after contacting the conversion agent.
[0060] Conversion Agents
[0061] Conversion agents suitable for use with the methods of the
present invention include, but are not limited to metal oxides,
metal hydroxides, polymorphs of calcium carbonate and combinations
and mixtures thereof. In some embodiments, the conversion agent
comprises a metal oxide. Metal oxides suitable for use in the
methods of the present invention include, but are not limited to,
magnesium oxide, aluminum oxide, titanium oxide, and combinations
and mixtures thereof. Metal hydroxides suitable for use with the
methods of the present invention include, but are not limited to,
magnesium hydroxide, aluminum hydroxide, titanium hydroxide, and
combinations and mixtures thereof. Polymorphs of calcium carbonate
suitable for use as a conversion agent with the methods of the
present invention include, but are not limited to, aragonite. In
some embodiments, magnesium oxide is used as a conversion agent to
treat water. In some embodiments, magnesium hydroxide is used as a
conversion agent to treat water. In still yet other embodiments, a
combination of magnesium oxide and hydroxide are used as a
conversion agent to treat water.
[0062] In some embodiments the conversion agent selected for use
with the methods of the present invention is slightly soluble in
water. In some embodiments, the conversion agent selected for use
with the methods of the present invention is insoluble in water. In
some embodiments, a conversion agent selected for use with the
methods of the present invention has a solubility of less than
about 0.01 g/100 mL in water. In some embodiments, low solubility
is preferred for longer conversion agent activity.
[0063] In some embodiments, water contacted with a conversion agent
forms a calcium precipitate. The calcium precipitate formed using
the methods of the present invention is such that the precipitate
flows through the water source harmlessly. That is, in some
embodiments, unlike conventional water treatment systems, there is
not a need to filter or remove the precipitate from the treated
water.
[0064] In some embodiments, the conversion agent used with the
methods of the present invention is in solid form. By the term
"solid" as used to describe the conversion agent composition, it is
meant that the hardened composition will not flow perceptibly and
will substantially retain its shape under moderate stress or
pressure or mere gravity, as for example, the shape of a mold when
removed from the mold, the shape of an article as formed upon
extrusion from an extruder, and the like. The degree of hardness of
the solid composition can range from that of a fused solid block
which is relatively dense and hard, for example, like concrete, to
a consistency characterized as being malleable and sponge-like,
similar to caulking material.
[0065] The composition comprising a conversion agent can further
comprise additional functional ingredients. Additional functional
ingredients suitable for use with the methods of the present
invention include any materials that impart beneficial properties
to the conversion agent, the water source being treated, or any
combination thereof. For example, in some embodiments the
conversion agent comprises a solid media bed of particles, e.g.,
magnesium oxide particles. Additional functional ingredients may be
added that aid in the prevention of "cementing" of the media bed,
i.e., agglomeration of the particles, as it is contacted with a
water source.
[0066] In some embodiments, the additional functional ingredient
comprises a polymorph of calcium carbonate. Exemplary polymorphs of
calcium carbonate suitable for use with the methods of the present
invention include, but are not limited to, aragonite, calcite,
vaterite and mixtures thereof. In some embodiments, the additional
functional ingredient comprises aragonite. In other embodiments,
the functional ingredient comprises calcite.
[0067] In some embodiments, the additional functional ingredient
comprises a mixed cation compound of calcium and magnesium ions. In
some embodiments, the additional functional material comprises
calcium magnesium carbonate, some natural minerals of which may
also be known by the name dolomite.
[0068] In some embodiments, the composition comprising a conversion
agent further comprises about 10 wt % to about 90 wt % of an
additional functional ingredient. In other embodiments, the
composition comprising a conversion agent further comprises about
25 wt % to about 75 wt % of an additional functional ingredient. In
still yet other embodiments, the composition comprising a
conversion agent further comprises about 50 wt % of an additional
functional ingredient. In some embodiments, the composition
comprising a conversion agent further comprises about 25 wt % of
aragonite. In some embodiments, the composition comprising a
conversion agent further comprises about 25 wt % of calcite. It is
to be understood that all values and ranges between these values
and ranges are encompassed by the methods of the present
invention.
[0069] Water Source
[0070] In some aspects, the methods of the present invention
comprise treating a water source such that the solubilized hardness
of the water is reduced. The term "water source" as used herein,
refers to any source of water having a hardness that would be
benefited by treatment in accordance with the methods of the
present invention. Exemplary water sources suitable for treatment
using the methods of the present invention include, but are not
limited to, water from a municipal water source, or private water
system, e.g., a public water supply or a well. The water can be
city water, well water, water supplied by a municipal water system,
water supplied by a private water system, and/or water directly
from the system or well. In some embodiments, the water source is
not an industrial process water, e.g., water produced from a
bitumen recovery operation. In other embodiments, the water source
is not a waste water stream.
[0071] In some embodiments the water source has a pH of about 6 to
about 9 prior to treatment using the methods of the present
invention. In some embodiments, the water source has a pH of
between about 8 and about 12 prior to treatment using the methods
of the present invention. In some embodiments, the water source
will have a higher, i.e., more alkaline, pH after treatment in
accordance with the methods of the present invention.
[0072] In some embodiments, the temperature of the water prior to
contact with a conversion agent is at an ambient, i.e., room
temperature, i.e., about 64.degree. F. to about 75.degree. F. In
some embodiments, the temperature of the water prior to contact
with a conversion agent is at a temperature less than ambient
temperature. In other embodiments the water source is heated prior
to contact with a conversion agent. In some embodiments, heating
the water source prior to contact with a conversion agent results
in a greater reduction in the amount of scale formed on a surface,
and a greater reduction in the solubilized water hardness than if
the water source is not heated.
[0073] In some embodiments the temperature of the water prior to
contact with a conversion agent is greater than about 100.degree.
F., greater than about 120.degree. F., or greater than about
150.degree. F. In some embodiments, the water temperature prior to
contact with a conversion agent is between about 100.degree. F. and
about 200.degree. F. In other embodiments, the water temperature is
between about 120.degree. F. and about 140.degree. F., between
about 140.degree. F. to about 160.degree. F., or between about
65.degree. F. to about 180.degree. F. prior to contact with a
conversion agent. It is to be understood that all values and ranges
between these values and ranges are encompassed by the methods of
the present invention.
[0074] In some aspects, the present invention provides methods for
reducing solubilized water hardness comprising contacting a water
source with a composition comprising a conversion agent. The step
of contacting can include, but is not limited to, running the water
source over or through a solid source, e.g., a column, cartridge,
or tank, comprising the conversion agent. The contact time is
dependent on a variety of factors, including, for example, the pH
of the water source, the hardness of the water source, and the
temperature of the water source. In some embodiments, the water
source has a contact time of between about 30 seconds and about
6000 seconds with the source of conversion agent. In some
embodiments, the water source has a contact time of between about
120 seconds and about 1800 seconds with the source of conversion
agent. It still yet other embodiments, the water source has a
contact time of between about 200 seconds and about 1200 seconds
with the source of conversion agent. It is to be understood that
all values and ranges between these values and ranges are
encompassed by the methods of the present invention.
[0075] In some embodiments, the methods of the present invention
substantially reduce the solubilized hardness of the water source.
The amount of water hardness reduction achieved is dependent on a
variety of factors, including, but not limited to the pH of the
water source, the temperature of the water source, and the initial
water hardness.
[0076] For example, in some embodiments the solubilized water
hardness is reduced by about 25%. In some embodiments, the
solubilized water hardness is reduced by about 50%. In still yet
other embodiments, the solubilized water hardness is reduced by
about 75%. In still yet other embodiments, the solubilized water
hardness is reduced by about 90%.
[0077] In some aspects, the present invention provides methods for
reducing or inhibiting scale formation in an aqueous system. In
some embodiments, an aqueous system, i.e., a water source, is
contacted with a conversion agent, e.g., a metal oxide or
hydroxide. Without wishing to be bound by any particular theory, it
is thought, that the resulting treated aqueous system will have a
reduced solubilized hardness. In some embodiments, the resulting
treated aqueous system will have a reduced solubilized calcium
hardness. This reduction in hardness will reduce the amount of
scale formed on surfaces contacted by the water source. Thus, use
of a water source treated in accordance with the methods of the
present invention will inhibit or reduce the amount of water scale
formed on a surface.
[0078] For example, in some embodiments the amount of scale
formation is reduced by about 25%. In some embodiments, the amount
of scale formation is reduced by about 50%. In still yet other
embodiments, the amount of scale formation is reduced by about 80%.
In still yet other embodiments, the amount of scale formation is
reduced by about 100%.
[0079] The methods of the present invention are especially
effective at removing or preventing scale formation wherein the
scale comprises calcium salts, e.g., calcium phosphate, calcium
oxalate, calcium carbonate, calcium bicarbonate or calcium
silicate. The scale which is intended to be prevented or removed by
the present invention may be formed by any combination of the
above-noted ions. For example, the scale may involve a combination
of calcium carbonate and calcium bicarbonate. The scale typically
comprises at least about 90 wt % of inorganic material, more
typically at least about 95 wt % of inorganic material, and most
typically at least about 99 wt % of inorganic material.
[0080] Methods of Using a Treated Water Source in a Downstream
Cleaning Process
[0081] In some aspects, the present invention provides a method of
using a treated water source to clean an article. It has been found
that use of a treated water source has many advantages in
downstream cleaning processes compared to use of a non-treated
water source. For example, use of a water source treated in
accordance with the methods of the present invention increases the
efficacy of conventional detergents. Use of a treated water source
also allows for the use of specific environmentally friendly
detersive compositions, e.g., those free of chelants or
sequestrants, or phosphorous.
[0082] In some embodiments, the methods of the present invention
comprise treating a water source with a composition comprising a
conversion agent, wherein the conversion agent causes calcium
hardness ions in the water source to substantially precipitate in a
non-calcite crystalline form that does not need to be removed from
the water source, such that the solubilized hardness of the water
is substantially reduced. A use solution can then be formed with
the treated water and a detersive composition. The article or
articles to be cleaned are then contacted with the use solution,
such that the article(s) is cleaned.
[0083] In some embodiments, the method further comprises rinsing
the article. The article can be rinsed with treated water, or with
untreated water. In some embodiments, the article is rinsed using
treated water. A rinse aid can also be applied to the article after
it has been washed.
[0084] Any conventional detersive composition can be used with the
methods of the present invention. The detersive composition can
comprise a cleaning composition, a rinse agent composition, a
drying composition or any combination thereof. Without wishing to
be bound by any particular theory, it is thought that use of a
treated water source in a cleaning process increases the efficacy
of the detersive composition due to the reduced amount of
solubilized hardness minerals in the water source, e.g.,
solubilized calcium hardness ions. It is known that solubilized
hardness ions combine with soap and detergents to form a scale or
scum. Further, solubilized hardness ions limit the amount of lather
formed with soaps and detergents. Reducing the amount of these
solubilized hardness ions can therefore reduce the amount of these
detrimental side effects.
[0085] Detersive compositions for use with the methods of the
present invention can include, but are not limited to, detergent
compositions, rinse agent compositions, or drying agent
compositions. Exemplary detergent compositions include warewashing
detergent compositions, laundry detergent compositions, CIP
detergent compositions, environmental cleaning compositions, hard
surface cleaning compositions (such as those for use on counters or
floors), motor vehicle washing compositions, and glass cleaning
compositions. Exemplary rinse agent compositions include those
compositions used to reduce streaking or filming on a surface such
as glass. Exemplary drying agent compositions include dewatering
compositions. In the vehicle washing industry, it is often
desirable to include a dewatering step where a sheeting or beading
agent is applied to the vehicle exterior.
[0086] Exemplary articles that can be treated, i.e., cleaned, with
the use solution comprising a detersive composition and treated
water include, but are not limited to motor vehicle exteriors,
textiles, food contacting articles, clean-in-place (CIP) equipment,
health care surfaces and hard surfaces. Exemplary motor vehicle
exteriors include cars, trucks, trailers, buses, etc. that are
commonly washed in commercial vehicle washing facilities. Exemplary
textiles include, but are not limited to, those textiles that
generally are considered within the term "laundry" and include
clothes, towels, sheets, etc. In addition, textiles include
curtains. Exemplary food contacting articles include, but are not
limited to, dishes, glasses, eating utensils, bowls, cooking
articles, food storage articles, etc. Exemplary CIP equipment
includes, but is not limited to, pipes, tanks, heat exchangers,
valves, distribution circuits, pumps, etc. Exemplary health care
surfaces include, but are not limited to, surfaces of medical or
dental devices or instruments. Exemplary hard surfaces include, but
are not limited to, floors, counters, glass, walls, etc. Hard
surfaces can also include the inside of dish machines, and laundry
machines. In general, hard surfaces can include those surfaces
commonly referred to in the cleaning industry as environmental
surfaces.
[0087] In some embodiments, the detersive composition for use with
the methods of the present invention comprises a detergent that is
substantially free of a chelant sequestrant, and/or threshold
agent, e.g., an aminocarboxylic acid, a condensed phosphate, a
phosphonate, a polyacrylate, or the like. Without wishing to be
bound by any particular theory, it is thought that because the
methods of the present invention substantially reduce the
solubilized hardness ions in the water source, when used with a
detergent, there is a substantially reduced or eliminated need to
include chelating agents, sequestrants, or threshold agents in the
detergent composition in order to handle the hardness ions.
[0088] In some embodiments, the detergent for use with the methods
of the present invention is substantially free of a chelating agent
or sequestrant and comprises an insoluble magnesium compound, an
alkali metal carbonate, and water. In some embodiments, the
detergent composition for use with the methods of the present
invention is a detergent composition described in U.S. patent
application Ser. No. ______ entitled "Solid Cleaning Compositions
of Magnesium Compounds And Methods of Making and Using them"
(Attorney Docket No. 2454USU1), the entire contents of which are
hereby incorporated by reference.
[0089] In some embodiments, the detersive composition may include
other additives, including conventional additives such as bleaching
agents, hardening agents or solubility modifiers, defoamers,
anti-redeposition agents, threshold agents, stabilizers,
dispersants, enzymes, surfactants, aesthetic enhancing agents
(i.e., dye, perfume), and the like. Adjuvants and other additive
ingredients will vary according to the type of composition being
manufactured. It should be understood that these additives are
optional and need not be included in the cleaning composition. When
they are included, they can be included in an amount that provides
for the effectiveness of the particular type of component.
[0090] In some aspects, the present invention provides an apparatus
for treating a water source used in a cleaning or washing process.
The apparatus can be, for example, for use in an automatic
warewashing machine, an automatic textile washing machine, and/or
an automatic vehicle washing machine. The apparatus can be used
both in commercial settings, e.g., at a restaurant, a hospital, and
in residential settings, e.g., a private home, or apartment
building.
[0091] Referring to FIG. 1, a schematic of an apparatus of the
present invention is shown at reference 10. The apparatus
comprises: an inlet 12 for providing the water source to a
treatment reservoir 14; a treatment reservoir 14 comprising a
conversion agent 16; an outlet 18 for providing treated water from
the treatment reservoir; and a treated water delivery line 20 for
providing the treated water to the selected cleaning device. In
some embodiments, there is no filter between the outlet and the
treated water delivery line. A flow control device 22 such as a
valve 24 can be provided in the treated water delivery line 18 to
control the flow of the treated water into the selected end use
device, e.g., a warewashing machine, a laundry washing machine.
[0092] In some embodiments, the conversion agent is contained in a
treatment reservoir in the apparatus. The reservoir can be for
example, a tank, a cartridge, a filter bed of various physical
shapes or sizes, or a column. In some embodiments, the treatment
reservoir comprising a conversion agent is resin free, i.e., it
does not contain a material that contains univalent hydrogen,
sodium or potassium ions, which exchange with divalent calcium and
magnesium ions in the water source. In some embodiments, the
reservoir is pressurized. In other embodiments, the reservoir is
not pressurized. One reservoir or multiple reservoirs may be used
with the methods of the present invention. For example, the water
source may be passed over a plurality of reservoirs, in the same or
in separate containers, comprising the same or different conversion
agents. The reservoirs may be arranged in series or in
parallel.
[0093] In some embodiments, the conversion agent is in the form of
an agitated bed or column. The bed or column may be agitated to
avoid "cementing," i.e., agglomeration of the solid conversion
agent once contacted with the water source. The bed or column can
be agitated by any known method including, for example, by the flow
of water through the column, fluidization, mechanical agitation,
high flow backwash, recirculation, and combinations thereof. In
some embodiments, the solid conversion agent comprises a fluidized
bed, e.g., a column or a cartridge, in the treatment reservoir.
Fluidization is obtained by an increase in the velocity of the
fluid, e.g., water, passing through the bed such that it is in
excess of the minimum fluidization velocity of the media.
[0094] In some embodiments, the entire treatment reservoir can be
removable and replaceable. In other embodiments, the treatment
reservoir can be configured such that the bed of conversion agent
contained within the treatment reservoir is removable and
replaceable. In some embodiments, the treatment reservoir comprises
a removable, portable, exchangeable cartridge comprising a
conversion agent, e.g., magnesium oxide.
[0095] In some aspects, the present invention provides a system for
use in a cleaning process. The system comprises providing a water
source to an apparatus for treating the water source. In some
embodiments, the apparatus for treating the water source comprises:
(i) an inlet for providing the water source to a treatment
reservoir; (ii) a treatment reservoir comprising a conversion
agent; (iii) an outlet for providing treated water from the
treatment reservoir; and (iv) a treated water delivery line for
providing the treated water to the automatic warewashing machine.
In some embodiments, a device, e.g., a screen, is present in the
treatment reservoir in order to keep the conversion agent contained
within the treatment reservoir as the fluid is passing over or
through it. In some embodiments, there is no filter between the
outlet and the treated water delivery line. Once the water has been
treated, the treated water is provided to an automatic washing
machine, e.g., an automatic ware washing machine, a vehicle washing
system, an instrument washer, a clean in place system, a food
processing cleaning system, a bottle washer, and an automatic
laundry washing machine, from the treated water delivery line of
the apparatus. Any automatic washing machine that would benefit
from the use of water treated in accordance with the methods of the
present invention can be used. The treated water is then combined
with a detersive composition in the washing machine to provide a
use composition. Any detersive composition can be used in the
system of the present invention, for example, a cleaning
composition, a rinse agent composition or a drying agent
composition. The articles to be cleaned are then contacted with the
use solution in the automatic washing machine such that they are
cleaned.
[0096] The water treatment methods and systems of the present
invention can be used in a variety of industrial and domestic
applications. The water treatment methods and systems can be
employed in a residential setting or in a commercial setting, e.g.,
in a restaurant, hotel, hospital. For example, a water treatment
method, system, or apparatus of the present invention can be used
in: ware washing applications, e.g., washing eating and cooking
utensils and other hard surfaces such as showers, sinks, toilets,
bathtubs, countertops, windows, mirrors, and floors; in laundry
applications, e.g., to treat water used in an automatic textile
washing machine at the pre-treatment, washing, souring, softening,
and/or rinsing stages; in vehicle care applications, e.g., to treat
water used for pre-rinsing, e.g., an alkaline presoak and/or low pH
presoak, washing, polishing, and rinsing a vehicle; industrial
applications, e.g., cooling towers, boilers, industrial equipment
comprising heat exchangers; in food service applications, e.g., to
treat water lines for coffee and tea brewers, espresso machines,
ice machines, pasta cookers, water heaters, steamers and/or
proofers; in healthcare instrument care applications, e.g.,
soaking, cleaning, and/or rinsing surgical instruments, treating
feedwater to autoclave sterilizers; and in feedwater for various
applications such as humidifiers, hot tubs, and swimming pools
[0097] In some embodiments, the water treatment methods and systems
of the present invention can be applied at the point of use. That
is, a water treatment method, system, or apparatus of the present
invention can be applied to a water source immediately prior to the
desired end use of the water source. For example, an apparatus of
the present invention could be employed to a water line connected
to a household or restaurant appliance, e.g., a coffee maker, an
espresso machine, an ice machine. An apparatus employing the
methods of the present invention can also be included as part of an
appliance which uses a water source, e.g., a water treatment system
built into a coffee maker, or ice machine.
[0098] Additionally, an apparatus for employing the water treatment
methods of the present invention can be connected to the water main
of a house or business. The apparatus can be employed in line
before the hot water heater, or after the hot water heater. Thus,
an apparatus of the present invention can be used to reduce
solubilized water hardness in hot, cold and room temperature water
sources.
EXAMPLES
[0099] The present invention is more particularly described in the
following examples that are intended as illustrations only, since
numerous modifications and variations within the scope of the
present invention will be apparent to those skilled in the art.
Unless otherwise noted, all parts, percentages, and ratios reported
in the following examples are on a weight basis, and all reagents
used in the examples were obtained, or are available, from the
chemical suppliers described below, or may be synthesized by
conventional techniques.
Example 1
Water Treatment with a Conversion Agent Comprising Low Water
Soluble Magnesium Media
[0100] The following experiments were performed to evaluate the
effect of various conversion agents on water hardness, and ware
washing applications.
[0101] (a) Ability of a Conversion Agent Comprising a Solid Source
of Magnesium Oxide to Reduce Solubilized Water Hardness
[0102] The ability of a conversion agent comprising a solid source
of insoluble magnesium oxide to treat water, e.g., reduce
solubilized water hardness was evaluated. For this experiment water
was passed through a media bed of magnesium oxide particles. The
particles had an average size of about 900 microns. The media was
held in a tank.
[0103] The amount of calcium and magnesium ions in the water was
measured before and after passing over the bed comprising the
conversion agent. The total dissolved solids (TDS), water hardness,
and pH were also measured both before and after treatment. The
table below summarizes the results.
TABLE-US-00001 TABLE 1 Before Treatment After Treatment pH 7.6 9.3
TDS (ppm) 360.5 201.4 Water Hardness (grains) 18 12 Ca.sup.++ ions
present (ppm) 66 9 Mg.sup.++ ions present (ppm) 28 48
[0104] As can be seen from this table, the pH of the treated water
rose slightly after treatment. Without wishing to be bound by any
particular theory, it is thought that this is due to the magnesium
oxide in the media bed dissolving into Mg.sup.++ and OH.sup.- once
contacted by the water. It was also observed that the total
solubilized water hardness decreased by about 35%, and the total
solubilized Ca.sup.++ decreased by about 86%. Overall, it was
observed that the treatment of a water source with the solid
conversion agent, i.e., magnesium oxide, provided beneficial
effects, e.g., reduced solubilized water hardness, and reduced
amounts of total dissolved solids, to the treated water source.
[0105] (b) Addition of Calcite to a Conversion Agent
[0106] Another test was run to determine the effect of adding
calcite to the media bed comprising the conversion agent, i.e.,
magnesium oxide. It was theorized that the calcite would prevent
"cementing" of the magnesium oxide during use over time, as
magnesium oxide is known to agglomerate and form a solid mass. The
amount of magnesium ions and calcium ions in the treated water were
measured after treatment with various concentrations of magnesium
oxide and calcium. The table below summarizes the results.
TABLE-US-00002 TABLE 2 Percent Make-Up in Treatment Tank (%)
MgO/Calcite 100/0 75/25 50/50 25/75 0/100 Treated Water Composition
Mg.sup.++(ppm) 48.3 45.3 39.0 36.8 26.0 Ca.sup.++(ppm) 8.96 13.5
25.1 37.3 63.9
[0107] Drinking glasses were also washed in a ware washing machine
using water treated with the above MgO/Calcite formulations. After
100 cycles the glasses were evaluated for spotting and filming,
although filming was taken to be a more reliable indicator of glass
appearance in the test. Heavily filmed glasses do not show spots
well because a heavy film prevents appearance of spots. FIG. 2
shows the glasses treated in this experiment. It was observed that
the glasses washed with the water comprising 100% MgO and no
calcite had little to no spotting. It was observed that the amount
of spotting and filming increased on the glasses as the amount of
MgO used decreased, and the amount of calcite increased.
[0108] (c) Addition of a Conversion Agent During a Ware Washing
Process
[0109] Another ware washing test on drinking glasses was run using
a tank comprising a conversion agent, i.e., magnesium oxide, and no
calcite. For this test, a Hobart AM-14 automatic ware washing
machine was used. The water prior to treatment had a hardness of 17
grains. The magnesium oxide treated water was supplied before the
sump in the machine, thereby also having an effect during the rinse
cycle. No detergent or rinse aid was applied to the glasses. As a
control, a glass was washed for 100 cycles with untreated water.
After 100 cycles the glasses were evaluated for spotting and
filming. FIG. 3 shows the results of this experiment. It was
observed that the glass ware treated with water and a conversion
agent had no filming or scaling, unlike the control glass which had
substantial filming and spotting.
[0110] (d) Addition of a Conversion Agent During a Ware Washing
Process with Detergent Formulations with and without a Chelant or
Sequestrant
[0111] A water treatment system comprising a solid source of a
conversion agent was attached to an automatic ware washing system.
The conversion agent used in this study comprised magnesium oxide.
For this test, a Hobart AM-14 machine was used. The water prior to
treatment had a hardness of 17 grains.
[0112] Two detergent formulations were tested. The first comprised
about 1000 ppm of a commercially available detergent with about 35%
chelant, Apex Power.RTM., available from Ecolab Inc. A rinse aid
was applied after the glasses were washed with this detergent.
[0113] The second detergent was free of a chelant or sequestering
agent, and comprised about 32% NaOH, about 35% RU silicate (a
sodium silicate available from Philadelphia Quartz), about 0.6%
polyether siloxane, about 2% Plurionic N3.RTM. (a copolymer
available from BASF), about 1% of a nonionic defoaming agent, about
9.5% soda ash, about 12% sodium sulfate, and about 1% water. About
650 ppm of the chelant free detergent was used. No rinse aid was
used with the chelant free detergent. The glasses were washed with
either formulation for 100 cycles.
[0114] The glasses washed with the chelant free detergent were
washed using water treated with a conversion agent of the present
invention, i.e., magnesium oxide. The glasses washed with the
commercially available detergent comprising a builder, i.e., Apex
Power.RTM., were washed using untreated water.
[0115] FIG. 4 shows the glasses after completion of the 100 cycle
test. As can be seen from this figure, the glass washed using a
chelant free detergent and treated water, had substantially less
filming and spotting than the glasses washed with Apex Power.RTM.
and a rinse aid, but with untreated water. Further, it was observed
that after the 100 cycles were completed, the inside of the machine
used with the chelant free detergent and the treated water visually
looked better than the machine used with the Apex Power.RTM. and
the untreated water.
[0116] This test was repeated, however, a rinse aid was added after
the wash cycle. About 2.33 mL of the rinse aid was added per cycle.
FIG. 5 shows the glasses after washing with each formulation. As
can be seen in this figure, when a rinse aid was added, both
glasses had an improved visual appearance. However, the glass
treated with the chelant free detergent, and the treated water,
still had substantially less spotting and filming than the glass
washed with untreated water, and Apex Power.RTM..
[0117] The same test was performed, this time using soiled
glassware. Glasses were soiled with 100% whole milk and a dried
protein/starch/grease combined soil. Soiled glasses were washed for
10 cycles, as described above, with either Apex Power.RTM., or the
chelant free detergent composition described above. The glasses
were re-soiled between each cleaning cycle with additional starch
and protein soil. The glasses washed with Apex.RTM. were washed
with untreated water, and the glasses washed with the chelant free
detergent were washed with water treated with a conversion agent,
i.e., magnesium oxide.
[0118] The results are shown in FIG. 6. As can be seen from this
figure, the glasses washed with the chelant free detergent and the
treated water had less spotting and filming than those washed using
Apex Power.RTM.. It was also observed that the glasses washed with
Apex Power.RTM. and untreated water had a slightly bluish tint, and
those washed with the treated water had no visual blue
spotting.
Example 2
Effect of Various Metal Oxides and Salts on Hard Water
[0119] A variety of tests were run to determine the effect various
metal oxides and salts have on water hardness.
[0120] (a) Effect of Various Metal Complexes on Hard Water
[0121] The following test was run to determine the effect of
various metal complexes, i.e., oxides, carbonates, and hydroxides,
with or without calcite or aragonite, on water hardness. The
starting water had a hardness of about 23 grains. Different metal
complexes were added to the water, and the hardness of the water
was measured thereafter. For these experiments, about 216 g of
treatment agent was added to a beaker containing about 500 mL of
hard water. After stirring the contents the beaker for 20 minutes,
an aliquot was removed and filtered through a 0.2 micron syringe
filter to remove any suspended particulate. Then the filtered
sample was titrated for total water hardness (Ca.sup.++ and
Mg.sup.++) using a water test kit. The following table summarizes
the results.
TABLE-US-00003 TABLE 3 Water Hardness after treatment Treatment
(grains) starting water 23 alum. oxide 6 alum. oxide + aragonite 8
alum. oxide + calcite 4 iron oxide 24 iron oxide + aragonite 26
iron oxide + calcite 24 mag. carbonate 24 mag. carbonate +
aragonite 50 mag. carbonate + calcite 23 mag. hydroxide + aragonite
26 mag. oxide 8 titanium oxide 3 titanium oxide + aragonite 12
titanium oxide + calcite 9 zinc oxide 23 zinc oxide + aragonite 22
zinc oxide + calcite 23
These results are also graphically depicted in FIG. 7. As can be
seen from the table above, and FIG. 7, addition of aluminum oxide,
magnesium oxide, or titanium oxide reduced the water hardness more
than the other metal oxides tested. For example, the addition of
aluminum oxide resulted in more than about a 70% reduction in the
water hardness, the addition of titanium oxide resulted in more
than about an 80% reduction in water hardness, and the addition of
magnesium oxide resulted in more than about a 60% reduction in
water hardness.
[0122] It was also found that the addition of aragonite and calcite
with a metal oxide did not increase the reduction in the water
hardness as much when aluminum oxide, magnesium oxide or titanium
oxide was added to the water alone. However, the use of aluminum
oxide, titanium oxide or magnesium oxide with calcite or aragonite
still reduced the water hardness more than the other metal oxides
tested, i.e., iron oxide, and zinc oxide.
[0123] (b) Evaluation of Potential Water Softening Agents by
Wetting Effect Change
[0124] Various metal oxides, hydroxides, and salts were tested to
determine their ability to act as water softeners. Solutions of
about 1000 ppm of the various compositions were prepared. Smooth
ceramic tiles were rinsed with the solutions and wiped dry. The
contact angle of deionized water on the surface of the tiles was
measured. The tiles were then rinsed under 17 grain water hardness,
dried, and the contact angle was re-measured. The results are shown
in the table below.
TABLE-US-00004 TABLE 4 before after ratio hard hard after/before
water water hard water Treatment rinse rinse rinse 0.1% titanium
oxide 24 17 0.7 0.1% aluminum oxide 26 19 0.7 1% magnesium oxide 18
15 0.8 1% magnesium oxide nanoparticles 18 15 0.8 1% magnesium
hydroxide 22 19 0.9 0.001% magnesium hydroxide 23, 17, 15 0.7 25
0.01% magnesium hydroxide 13, 18, 15 0.9 18 0.1% magnesium
hydroxide 18, 16 16, 18 0.9, 1.1 untreated 37, 36 48 1.3 0.1%
magnesium chloride 21 28 1.3 0.1% zinc oxide 16 22 1.4 0.1% calcium
chloride 20 35 1.8 0.1% magnesium sulfate 11 24 2.2 0.1% silicon
oxide nanoparticles 9 23 2.6 (Snowtex N, Nissan Chemical) 0.1%
silicon oxide nanoparticles 10 26 2.6 (Snowtex 40, Nissan Chemical)
0.1% silicon oxide nanoparticles 6 22 3.7 (Snowtex ZL, Nissan
Chemical) 0.1% sodium hydroxide 2 21 10.5
[0125] It was theorized that a lower ratio of the contact angle of
water before and after hard water rinsing of the substrate
correlates to improved protection of the substrate from the hard
water as it shows less impact of water hardness ions on the surface
wetting. As can be seen from this table, the ratio of the contact
angle after/before the hard water rinse was about 1 or less for the
titanium oxide, aluminum oxide, and the magnesium oxide and
hydroxide solutions tested. Based on these results, it was
theorized that these solutions would likely soften water. The
silicon oxide nanoparticles and sodium hydroxide had the highest
change in contact angle.
[0126] (c) Evaluation of Potential Water Softening Agents by
Calcium Selective Electrode
[0127] Various metal oxides, hydroxides, and salts were tested to
determine their ability to act as water softeners. Solutions of the
various compositions were prepared. To prepare the solutions, equal
volumes of the treatment were mixed with about 17 grain hard water
which is about 400 ppm water hardness. The mixtures were allowed to
stand for 10 minutes. An aliquot was removed and filtered through a
0.2 micron syringe filter to remove any non-solubilized material.
The level of dissolved calcium remaining in solution was determined
using a calcium selective electrode (e.g., model 9720BNWP from
ThermoScientific). The table below shows the results of this
test.
TABLE-US-00005 TABLE 5 Ca Remaining from 400 ppm Starting Solution
Treatment (ppm) untreated 400 calcite 300 aragonite 275 dolomite
300 magnesium oxide 275 magnesium hydroxide 275 aluminum oxide 150
iron oxide 300 silicon oxide 300 titanium oxide 250 clay 50
(sodium/magnesium/calcium aluminosilicate)* *turned to gel;
measured Ca level after filtration with a 0.2 micron filter.
[0128] As can be seen from this table, the solutions treated with
magnesium oxide and hydroxide, aluminum oxide, and titanium oxide
yielded the greatest reduction in the amount of calcium remaining
in the solution after treatment. The iron oxide and silicon oxide
decreased the amount of calcium remaining in the solution, at a
lower level than the other metal oxides tested.
Example 3
Use of a Conversion Agent in a Laundry Application
[0129] The effect of an inline conversion agent in a laundry
application was determined. To determine the effect of the
conversion agent on soil removal, soiled swatches are washed in a
device such as a Terg-o-tometer (United States Testing Co.,
Hoboken, N.J.). The Terg-o-tometer is a laboratory washing device
that consists of multiple pots that reside in a single
temperature-controlled water bath, with overhead agitators under
time and speed control. Wash test parameters include: wash
temperature, wash duration, pH, mechanical agitation, dose of
cleaning composition, water hardness, wash formula, and
cloth/liquor ratio. For this test, a pair of cylinders comprising a
conversion agent, i.e., magnesium oxide, was mounted inline,
upstream of a wash wheel in both hot and cold 17 grain water
lines.
[0130] After completing the appropriate exposure times the fabric
samples were removed. The detergent chemistries were immediately
flushed, and the swatches rinsed with cold synthetic 5 grain water
until 5 cycles of fills and rinses are complete. The swatches were
then laid flat and dried overnight on white polyester-cotton towels
before reflectance readings were taken using a spectrophotometer,
e.g., Hunter ColorQuest XE (reflectance) Spectrophotometer.
[0131] To determine the % soil removal (SR), the reflectance of the
fabric sample is measured on a spectrophotometer. The "L value" is
a direct reading supplied by the spectrophotometer. L generally is
indicative of broad visible spectrum reflectance, where a value of
100% would be absolute white. The % soil removal is calculated from
the difference between the initial (before washing) lightness (L)
value and the final L value (after washing):
SR=((L.sub.final-L.sub.initial)/(96-L.sub.initial)).times.100%
[0132] Two detergent compositions were used in this study. The
first comprised a mixture of chelant/sequestrant i.e., polyacrylate
polymer and sodium citrate, and the second was substantially free
of any chelant/sequestrant. Other than the presence or absence of a
chelant or sequestrant, the two detergent compositions were
equivalent and comprised about 3-75 wt % surfactant (if present),
about 5-50 wt % sequestrant (if present), about 0-50 wt %
alkalinity source and about 0-30 wt % of an active enzyme
composition.
[0133] The detergent composition with no chelant or sequestrant was
used with treated water, i.e., water contacted with the conversion
agent, and the detergent with the chelant/sequestrant mixture was
used with untreated water. The results are shown in FIG. 8. As can
be seen in this figure, the treated water/chelant free detergent
composition had a higher percent soil removal for the carbon cotton
blood milk soiled swatch. For the other swatches tested, the
detergent comprising a chelant/sequestrant used with untreated
water had a higher percent soil removal than the treated
water/chelant free detergent composition. However, for most of the
soils tested, the results were similar between both test
groups.
[0134] Another test was run to evaluate the encrustation of linens
when using a conversion agent of the present invention. For this
test, face cloths were washed for 20 cycles in the wash wheel using
17 grain water. Single face cloths were removed for analysis at 0,
5, 15, and 20 cycles. Two tests were run. For both tests, the
chelant/sequestrant free detergent described above was used. The
first test included an inline cylinder comprising a conversion
agent, and the second test used untreated water. The amount of
total ash and calcium content for the wash cloths were measured
using Inductively Coupled Plasma (ICP), and the results are shown
in the table below.
TABLE-US-00006 TABLE 6 Number of wash cycles 0 5 10 15 20 Percent
Ash Untreated 0.13 0.36 0.79 1.45 2.58 water Treated 0.13 0.19 0.65
0.76 0.83 water Calcium (ppm) Untreated 121 1120 2750 5240 10100
water Treated 125 750 3080 3570 4120 water
These results are also graphically depicted in FIGS. 9 and 10. As
can be seen from these results, the wash cloths washed using the
treated water had a much lower amount of ash remaining on the
cloths at each test point. For example, after 20 washes, the cloths
washed with treated water had about 32% of the amount of ash as
those washed with the untreated water. With respect to the amount
of calcium present on the wash clothes, at all test points other
than the 10 cycle test point, there was less calcium on the wash
cloths washed with treated water than those washed with untreated
water.
[0135] The amount of other metals on the wash cloths was also
measured. These results are shown in the table below.
TABLE-US-00007 TABLE 7 Number of wash cycles 0 5 10 15 20 Copper
(ppm) Untreated 37.7 18.4 25.2 27.4 35.1 water Treated 37.7 16.6 16
15.3 16 water Magnesium (ppm) Untreated 23.9 146 198 242 295 water
Treated 22.8 176 408 460 543 water Phosphorus (ppm) Untreated 10.3
18.6 29.1 42.2 61.5 water Treated 7.56 22.3 73.1 77.7 97 water Iron
(ppm) Untreated 4.73 3.81 3.88 3.67 3.69 water Treated 5.21 4.23
3.7 3.44 3.53 water
[0136] As can be seen from this chart, there was less copper in the
samples washed with the treated water than the untreated water.
However, there was more magnesium in the samples washed with the
treated water than the untreated water. This was to be expected, as
the conversion agent used for this study comprised magnesium, and
it may have partially dissolved over time.
Example 4
Effect of Water Temperature on Conversion Agents
[0137] The effect of the temperature of the water contacted by a
conversion agent on filming or spotting of glassware was
determined. Water with a hardness of 17 grains per gallon was
connected to a tank comprising a conversion agent of the present
invention, i.e., magnesium oxide. The tank was then connected to an
automatic dishwashing machine. Glasses in a glassware rack were set
into the dish machine. The dish machine was set to automatically
run 100 cycles back to back. A cycle is a complete wash, rinse, and
15 second pause. After 100 cycles the test was stopped and the
glasses were observed. No detergents were used for this test. The
test was repeated with hot water, i.e., about 140.degree. F. to
about 150.degree. F., and cold water. A control of untreated water,
i.e., no contact with the conversion agent was also run. The
glasses were visually inspected for spotting and filming. The
results are shown in FIG. 11.
[0138] In FIG. 11, the glass on the left was the glass treated with
a conversion agent and hot water, the glass in the middle of the
picture was treated with a conversion agent and cold water, and the
glass on the right was the control in cold water, i.e., not
contacted with the conversion agent. As can be seen from this
figure, the glass washed with the hot water contacted with the
conversion agent yielded substantially spotless glasses. The glass
treated with the cold water contacted with the conversion agent,
showed less filming than the control glass, but was not as clean or
clear as the hot water treated glass. These results were surprising
as calcium becomes less soluble, i.e., precipitates more, when
heated.
Example 5
Use of a Conversion Agent to Prevent Soap Scum
[0139] A test was run to determine the effect of treated water,
i.e., water contacted with a conversion agent, on the formation of
soap scum. The cold water stream to two showers was attached to a
tank comprising a solid source of a conversion agent, i.e.,
magnesium oxide. The cold water had 17 grain hardness before
treatment. The hot water was blended at the shower temperature
control knob, and comprised softened water.
[0140] After two months of running, the showers with and without
treatment were inspected. It was observed that the tiled shower
walls were more easily cleaned in the treated shower stalls,
compared to the non-treated shower stalls. The white film, i.e.,
soap scum, that formed was much more easily removed by wiping in
the shower stall that had treated water running in it. The
untreated stalls had a gummy soap scum that was sticky and harder
to wipe off. It was also noted that the shower heads in the
un-treated stalls had a much more visible white scale present than
those in the treated shower stalls.
[0141] The shower stalls were also subjected to a fizz test. An
acid was sprayed onto the shower walls and observed to see if there
was any fizzing upon contact. Fizzing indicates the presence of
calcium carbonate. The treated shower stalls showed no fizz when
sprayed with an acid. However, the shower stall without the
treatment showed a pronounced fizz when contacted by the acid.
Example 6
Use of a Water Treatment System for Vehicle Care
[0142] A test was run to determine the effect of using treated
water in a vehicle washing facility. Two tanks comprising a solid
source of magnesium oxide as a conversion agent were installed in
an automatic vehicle washing facility. The first tank (Tank 1) was
installed on the first presoak arch. The second tank (Tank 2) was
installed on the second presoak arch. The pH, TDS, and temperature
of the untreated hot water, treated water from Tank 1, and treated
water from Tank 2 were measured. The amount of SiO.sub.3 in the
untreated and treated waters was also measured.
[0143] FIG. 12 is a graphical depiction of the results of this
test. As can be seen in this figure, the tanks (Tank 1 and Tank 2)
were installed on Day 22. The TDS increased on this day. However,
by Day 32, the levels of TDS in the treated water were less than
the level of TDS in the untreated water. As can also be seen in
this figure, after the tanks were installed, the amount of
SiO.sub.3 in the water dropped significantly in the treated water
samples. It was also observed that the vehicles washed with treated
water during the pre-soak had a much lower amount of scaling after
being washed than those that had been washed using untreated water
during the presoak stage. Overall, using water treated in
accordance with the methods of the present invention had beneficial
effects when used at a vehicle washing facility.
OTHER EMBODIMENTS
[0144] It is to be understood that while the invention has been
described in conjunction with the detailed description thereof, the
foregoing description is intended to illustrate, and not limit the
scope of the invention, which is defined by the scope of the
appended claims. Other aspects, advantages, and modifications are
within the scope of the following claims.
[0145] In addition, the contents of all patent publications
discussed supra are incorporated in their entirety by this
reference.
[0146] It is to be understood that wherever values and ranges are
provided herein, all values and ranges encompassed by these values
and ranges, are meant to be encompassed within the scope of the
present invention. Moreover, all values that fall within these
ranges, as well as the upper or lower limits of a range of values,
are also contemplated by the present application.
* * * * *