U.S. patent application number 13/986763 was filed with the patent office on 2014-12-04 for ion enhancement.
The applicant listed for this patent is John Hill, Joseph A. King, Nicole A. Weulander. Invention is credited to John Hill, Joseph A. King, Nicole A. Weulander.
Application Number | 20140356453 13/986763 |
Document ID | / |
Family ID | 41255603 |
Filed Date | 2014-12-04 |
United States Patent
Application |
20140356453 |
Kind Code |
A1 |
King; Joseph A. ; et
al. |
December 4, 2014 |
Ion enhancement
Abstract
A method and apparatus for treating a body of water to kill
microorganisms by enhancing the concentration metal ions therein.
The apparatus comprising a dispenser with a first housing having a
water accessible compartment containing a source of a
N-halohydantoin compound for releasing the N-halohydantoin compound
when contacted by the body of water with the at least one
N-halohydantoin having the formula: ##STR00001## wherein R and R1
each independently comprises an alkyl group, and wherein X and Y
are independently selected from the group consisting of bromine,
chlorine and hydrogen and a second housing having a water
accessible compartment containing an insoluble metal ion donor for
releasing metal ions when contacted by the body of water containing
the N-halohydantoin.
Inventors: |
King; Joseph A.; (Wayzata,
MN) ; Hill; John; (Plymouth, MN) ; Weulander;
Nicole A.; (Savage, MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
King; Joseph A.
Hill; John
Weulander; Nicole A. |
Wayzata
Plymouth
Savage |
MN
MN
MN |
US
US
US |
|
|
Family ID: |
41255603 |
Appl. No.: |
13/986763 |
Filed: |
June 4, 2013 |
Current U.S.
Class: |
424/618 ;
210/198.1 |
Current CPC
Class: |
A01N 25/00 20130101;
C02F 1/766 20130101; C02F 1/76 20130101; A01N 59/16 20130101; C02F
1/688 20130101; A01N 59/16 20130101; A01N 59/16 20130101; A01N
25/00 20130101; C02F 2103/42 20130101; C02F 1/505 20130101; C02F
1/50 20130101; A01N 25/34 20130101; A01N 25/08 20130101; A01N 43/50
20130101; A01N 2300/00 20130101 |
Class at
Publication: |
424/618 ;
210/198.1 |
International
Class: |
A01N 25/00 20060101
A01N025/00; C02F 1/50 20060101 C02F001/50; A01N 59/16 20060101
A01N059/16 |
Claims
1. A method of treating a body of water to kill microorganisms by
enhancing a concentration of metal ions comprising: adding silver
salt to the body of water; and adding at least one N-halohydantoin
compound to the body of water to interact with the silver salt to
enhance a silver ion concentration in the body of water with the at
least one N-halohydantoin having the formula: ##STR00003## wherein
R and R1 each independently comprises an alkyl group and wherein X
and Y are independently selected from the group consisting of
bromine, chlorine and hydrogen.
2. The method of claim 1 wherein the step of adding at least one
N-halohydantoin compound comprises adding
1,3-Dichloro-5,5-dimethylhydantoin,
1,3-Dichloro-5-ethyl-5-methylhydatoin, or
monochloro-5-methylhydation to the body of water to interact with
the silver salt to enhance a silver ion concentration in the body
of water.
3. The method of claim 1 wherein the body of water comprises a body
of water support in a spa.
4. The method of claim 1 wherein the body of water comprises a body
of water support in a swimming pool.
5. The method of claim 1 wherein the step of adding at least one
N-halohydantoin compound comprises adding a combination of
1,3-Dichloro-5,5-dimethylhydation, 1,
3-Dichloro-5-ethyl-5-methylhydatoin, and
monochloro-5-methylhydation to the body of water to interact with
the silver salt to enhance a silver ion concentration in the body
of water.
6. The method of claim 1 wherein the step of adding a silver salt
to the body of water comprises adding silver chloride.
7. The method of claim 1 wherein the step of adding a silver salt
to the body of water comprises adding silver bromide.
8. The method of claim 1 wherein the step of adding a silver salt
to the body of water comprises adding silver chloride to the body
of water on a limestone carrier.
9. The method of claim 1 wherein the method of treating a body of
water comprises treating a body of recreational water for at least
partial human immersion therein by insertion of a tablet comprised
of silver chloride and the at least one N-halohydantoin
compound.
10. The method of claim 1 including the step of placing a dispenser
containing both the silver salt and the at least one
N-halohydantoin compound in the body of water and allowing water to
come into contact with both the silver salt and the at least one
N-halohydantoin compound.
11. A method of treating a body of water to kill microorganisms by
enhancing a concentration of metal ions comprising: adding a source
of metal ions to the body of water to generate metal ions in the
body of water; and adding at least one N-halohydantoin compound to
the body of water to enhance the metal ion concentration in the
body of water to thereby lessen the need for a supplemental biocide
with the at least one N-halohydantoin having the formula:
##STR00004## wherein R and R1 each independently comprises an alkyl
group, and wherein X and Y are independently selected from the
group consisting of bromine, chlorine and hydrogen.
12. The method of claim 11 wherein the source of metal ions
comprises silver chloride.
13. The method of claim 11 wherein the step of adding the source of
metal ions to the body of water comprises adding the source of
metal ions to the body of water on a of limestone carrier.
14. The method of claim 1 including the step of increasing the
temperature of the body of water to increase the dissolution of the
at least one N-halohydantoin compound in the body of water.
15. A dispenser for killing microorganisms in a body of water
comprising: a first housing having a water accessible compartment
containing a source of a N-halohydantoin compound for releasing the
N-halohydantoin compound when contacted by the body of water with
the at least one N-halohydantoin having the formula: ##STR00005##
wherein R and R1 each independently comprises an alkyl group, and
wherein X and Y are independently selected from the group
consisting of bromine, chlorine and hydrogen; and a second housing
having a water accessible compartment containing a metal ion donor
for releasing metal ions when contacted by the body of water
containing the 5,5-dimethyl hydantoin.
16. The dispenser of claim 15 wherein the metal ion donor comprises
an insoluble metal ion donor.
17. The dispenser of claim 15 wherein the source of N-halohydantoin
compound comprises a source of
1,3-Dichloro-5,5-dimethylhydantoin.
18. The dispenser of claim 15 wherein the source of N-halohydantoin
compound comprises a source of a combination of
1,3-Dichloro-5,5-dimethylhydation,
1,3-Dichloro-5-ethyl-5-methylhydatoin, and
monochloro-5-methylhydation.
19. The dispenser of claim 15 wherein the first housing and the
second housing are located in a dispenser having a set of openings
for the ingress and egress of water into the compartments in the
dispenser.
20. The dispenser of claim 15 wherein the silver ion donor
comprises silver chloride.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to currently pending U.S.
Provisional Application Ser. No. 61/126,105; filed on May 1, 2008;
titled ION ENHANCEMENT and is a continuation in part of U.S.
application Ser. No. 12/001,351 filed Dec. 11, 2007 which claims
priority form provisional application 60/878,016 filed Dec. 29,
2006 which are herby incorporated by reference.
FIELD OF THE INVENTION
[0002] This invention relates generally to water treatment and more
specifically, to the combination of a metal ion donor and a source
of a N-halohydantoin compound such as Dichlorodimethylhydatoin to
enhance the effectiveness of the metal ion donor in killing
microorganisms in a body of water.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0003] None
REFERENCE TO A MICROFICHE APPENDIX
[0004] None
BACKGROUND OF THE INVENTION
[0005] The concept of treating a body of water with a source of
metallic ions to kill bacteria in the body of water is known in the
art. Metallic ions such as a silver ion is an effective bactericide
for a body of water including recreational water such as swimming
pools, spas, jetted tubs or the like and is a preferred material
because it is generally easier and safer to use when compared to
other known bactericides or algaecides. A further advantage of
using silver ion as a bactericide is that silver ion minimizes the
need for pH adjustment to the body of water. However, if the
concentration of metallic ions such as silver ions in a body of
water is too low the ability to kill microorganisms is reduced or
lost. Conversely, if the concentration of metallic ions such as
silver ions is too high it can potentially lead to undesired
effects such as causing the user's skin to turn yellow and staining
clothes. Thus when silver ion is used as a disinfectant in a body
of water one generally wants to maintain the concentration of the
silver ion in a range that is effective killing microorganisms
without leading to the undesired effects associated with higher
levels of silver ions.
[0006] Traditionally, the sources of metallic ions used to kill
bacteria in recreational water have been limited to metallic ion
donors that are readily soluble in the recreational water in order
to maintain an effective concentration of the biocides in the body
of water. Silver chloride (AgCl), for example, has been a commonly
used bactericide for releasing silver ions into the body of water
to effectively kill microorganisms. Sodium bromide has also been
known to be used with silver chloride to provide an additional and
alternative water disinfection system.
[0007] One of the problems associated with the use of silver for
killing microorganisms is that silver has a tendency to complex
with other compounds and become increasingly insoluble thereby
reducing the effective microorganisms killing ability of the
silver. For example, it would not be anticipated that silver
chloride when used in combination with sodium bromide would be an
effective prolong disinfectant system because of the combination's
tendency to form insoluble silver bromide crystals, which are not
believed to be biologically active in aqueous environments.
However, it has been discovered that if silver forms a complex with
hydantoins, the silver will remain soluble to a higher degree
thereby retaining the silver's antimicrobial activity.
[0008] The present invention comprises a device and method for
using metal ion donors in combination with a hydantoin-based
structure to enhance a concentration of the metal ions in the body
of water or to enhance the solubility of metal ions from other
metal ion donors to retain the silver's antimicrobial activity in
the water.
SUMMARY OF THE INVENTION
[0009] Briefly, the present invention comprises a method and a
device for killing microorganisms in a body of water through the
enhancement of a concentration of metal ion donor even in
situations where the metal ion donors are generally insoluble or
not sufficiently soluble in the body of water to maintain an
effective concentration of the metal ion donor in soluble form in
the body of water. The device generally comprises a first housing
having a water accessible compartment containing a source of a
N-halohydantoin compound such as Dichlorodimethylhydatoin for
releasing the Dichlorodimethylhydatoin compound when contacted by
the body of water and a second housing having a water accessible
compartment containing a metal ion donor for releasing metal ions
to kill the microorganisms in the body of water when contacted by
water containing the Dichlorodimethylhydatoin compound to thereby
increase the effectiveness of the metal ion donor.
[0010] The method includes the steps of adding a metal ion donor to
the body of water and adding sufficient Dichlorodimethylhydatoin
compound to the body of water to interact with the metal ion donor
to enhance the metal ion concentration to effectively to kill
microorganisms. A further embodiment includes the tabletizing of
the Dichlorodimethylhydatoin compound with a metal ion donor so
that the combination can be placed in a body of water to be
disinfected.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 shows a graph of the measured dissolved silver
concentrations each week for the duration of a Spa Study 1;
[0012] FIG. 2 shows a graph of the measured dissolved silver
concentrations each week for the duration of a Spa Study 2 as
compared to the theoretical calculations;
[0013] FIG. 3 shows a graph of is the measured dissolved silver
concentrations each week for the duration of a Spa Study 3 as
compared to the theoretical calculations;
[0014] FIG. 4 is a table showing the effect that the bathers have
on the spa water of Spa Study 3.
[0015] FIG. 5 shows a dispenser having a housing with a compartment
containing a source of N-halohydantoin and a silver ion donor
comprising silver chloride therein; and
[0016] FIG. 6 shows a dispenser having a first housing containing a
source of N-halohydantoin and a second housing containing silver
ion donor comprising silver chloride therein.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0017] Hydantoin structures are known complexing agents in
silver-plating processes (R. J. Morrissey, U.S. Patent Application
Publication no. 2005/0183961). Studies performed by the inventor
have demonstrated that unhalogenerated hydantoins, such as
5,5-dimethylhydantoin (DMH), tend to increase levels of dissolved
silver. Studies performed by the inventor have also demonstrated
the halogenerated hydantoin such as Bromochlorodimethylhydantoin
(BCDMH) also tends to increase levels of dissolved silver. While
not fully understood it is believed that the aforementioned
increased in solubility is due to the soluble complex between
silver and hydantoin ring structures as it has been found the
silver remains soluble to a higher degree than expected.
[0018] The present invention has found that the qualities to
interact with metal ion donors such as silver chloride or silver
bromide to increase the solubility of the silver chloride or silver
bromide in a water environment and aid in the disinfection process
is not limited to just the halogenerated hydantoin BCDMH alone but
may include a broader category of N-halohydantoin compounds. For
example, the inventor has discovered that in addition to BCDMH, the
N-halohydantoin compound Dichlorodimethylhydatoin (DCDMH), which
has been used commercially in household automatic toilet bowl
cleaners and urinals, may also properly interact with silver from
sources such as silver chloride or silver bromide in a body of
recreational water such as spas, jetted tubs, swimming pools or the
like to form a soluble complex to enhance the effectiveness of the
silver in killing or controlling microorganisms in the body of
recreational water.
[0019] In order to verify the above, spa tests were performed using
silver chloride as the donor of metal ions to demonstrate the
enhancement of a silver concentration in a body of water when other
types of N-halohydantoin compounds such as DCDMH were used in
combination.
[0020] In the tests, a 450-gallon Marquise brand spa was used in
performing 3 tested to evaluate the potential use of DCDMH to
increase silver solubility in the presence of alternative
disinfection systems such as sodium bromide. The spa comprised a
dimensioned of 90''.times.90''.times.35.5'' with a water depth of
approximately 25'' without bathers. The spa featured 43 jets and
two pleated filter cartridges (Unicel 5CH-502), each having a
filtration area of 50 square feet. Spa water was maintained between
100.degree. F. (37.8.degree. C.) to 104.degree. F. (40.degree. C.)
and was circulated at least 2 hours daily.
[0021] In all three tests, the Dichlorodimethylhydantoin (DCDMH,
CAS No. 118-52-5) used was obtained from two sources, namely
Aldrich.RTM. and Lonza, Inc. located in Fair Lawn, N.J.. The DCDMH
obtained from Aldrich.RTM. comprised a fine powder material of
1,3-Dichloro-5,5-dimethylhydantoin with a 98% purity. The Lonza
DCDMH (Dantochlor.RTM.) comprised a combination of 80-83%
1,3-Dichloro-5,5-dimethylhydation, 16-17%
1,3-Dichloro-5-ethyl-5-methylhydatoin, 0-2%
monochloro-5-methylhydation. The DCDMH was introduced into the spa
via spa cartridges, which were fabricated by adding approximately
75-100 grams of DCDMH or Dantochlor to an empty Spa Frog.RTM. BCDMH
cartridge.
[0022] The source of silver ions was obtained from a King
Technology Inc. Spa Frog.RTM. Mineral Cartridge, which was randomly
selected from King Technology Inc.'s production inventories for use
in these tests and installed into an in-line system on the spa.
These mineral cartridges release silver ions into the spa in the
form of silver chloride. A different cartridge was used in each of
the three studies.
[0023] During all three tests, the spa was filled with fresh water
prior to the initiation of each of the three tests and the water
balanced according to Taylor Technologies Pool & Spa Water
Chemistry Manual. The pH of the water was reduced by the addition
of sodium bisulfate (pH Down Balancer, GLB, Alpharetta, Ga.) to a
range between 7.2 and 8.0. In Studies 2 and 3, a cartridge
containing the DCDMH was then installed into the In-Line Frog
System of the spa at the same time that the Spa Frog Mineral
Cartridge (silver source) was installed into the In-Line Frog
System of the spa. In Study 1, a Spa Frog.RTM. Mineral Cartridge
(silver source) was installed into the In-Line Frog System of the
spa. A cartridge containing the DCDMH was installed into the
In-Line Frog System of the spa three weeks after the start of the
testing period.
[0024] In Spa Study 1, water samples were taken and tested for a
ten week period. In Spa Study 2, water samples were taken and
tested for a seventeen week period. And for Spa Study 3, water
samples were taken and tested for a seven week period. It is noted
that in Spa Study 3, bathers were also introduced to the spa water
three weeks after the start of the testing period to test the
affect that bathers had on the spa water.
[0025] The Spa Frog.RTM. Mineral Cartridge was used to provide
silver ions from solid silver chloride (AgCI) distributed over a
porous matrix. Water flowing through the matrix comes into contact
with the AgCI resulting in the release of soluble silver ions to
water. DCDMH is also released to water resulting in the formation
of free chlorine and hydantoin structures. It would be anticipated
that soluble silver ions would be depleted from spa water through
the formation of silver chloride, an insoluble salt. However,
during each of the three spa studies the actual silver
concentration was higher than the calculated theoretical silver
concentration. This is due to the formation of a novel
silver-hydantoin complex, which we previously described. Although
silver chloride is described above as providing for the source of
silver ion, in the present embodiment the source of silver ion may
also comprises pure silver, silver metals, silver alloy or some
combination thereof because of the recognized bactericidal,
viricidal, and algaecidal properties of silver. The silver metals
can be introduced as metallic, zero valence material, or as metal
ions that can be introduced into the water by dissolution of
soluble metal salts, or by the dissolution of the metal itself. For
example, silver ion can be introduced into the water through the
dissolution of silver nitrate, or through the dissolution of
metallic silver as the result of conversion to silver oxide and
subsequent conversion of the oxide to more soluble silver species.
Mixtures of different salts, or of salts with metallic material,
may be combined together to provide the necessary concentration of
metal ions in the water.
Water Testing
[0026] Chemical tests were performed with water samples obtained
from each of the three spa studies for the chlorine concentration
and also, the dissolved silver concentration. Additionally, the spa
water's total alkalinity, turbidity, and pH were also tested and
maintained within ranges accepted by the industry. The ideal pH for
a spa is 7.20 to 7.60, however wider ranges are acceptable. In the
studies, the average pH for Spa Study 1 was 7.31, Spa Study 2
showed an average pH of 7.27, and Spa Study 3 had an average pH of
7.37, which were all within the low end of the ideal pH for a
spa.
[0027] Result of the test for dissolved silver concentration are
shown in FIG. 1 for Spa Study 1, are shown in FIG. 2 for Spa Study
2, and are shown in FIG. 3 for Spa Study 3. Chloride was tested
during Spa Studies 2 and Spa Study 3 to provide a means to
calculate the theoretical silver concentration based on the
solubility product of silver chloride. FIG. 4 shows the effect that
the bathers had on the spa water of Spa Study 3.
[0028] Free chlorine was measured to assess oxidizing potential for
disinfection. The average levels of free chlorine in Spa Studies 1,
2, and 3 were 0.52 ppm, 0.68 and 0.79 ppm. Control of free chlorine
concentrations in the observed range has not been previously
possible when a solid source of chlorine has been dispensed from a
simple cartridge device. It should be noted that although the
aforementioned low levels of chlorine may be inadequate when DCDMH
is used alone, the low levels of chlorine may be ideal for a
combined used with Spa Frog Minerals. Therefore, DCDMH may be
considered as an effective candidate for use with minerals in
spas.
[0029] Total chlorine was measured to assess all forms of chlorine
containing species present in spa water, some of which do not
participate in the disinfecting process. The average total chlorine
concentration for Spa Study 1 was 3.45 ppm (0.10 to 6.90 ppm
range), Spa Study 2 averaged 6.16 ppm (range 0.12 to 14.4 ppm), and
Spa Study 3 averaged 8.17 (range 0.17 to 15.8).
[0030] DCDMH's higher than expected concentrations of total
chlorine can be contributed to the structure in that DCDMH has two
chlorine atoms attached to a hydantoin ring. Additionally, it is
believed that only one chlorine atom detaches from the ring, while
the second may remain bonded. The hydantoin backbone with the one
chlorine atom attached may possibly interact with the DPD reagent
used to test for the total chorine resulting in higher total
chlorine reading than what really is present.
[0031] Furthermore, the high total chlorine can be utilized as a
chlorine bank, when there is a high demand. That is, it is
reasonable to propose that the last chlorine atom detaches itself
from the hydantoin ring with higher demand for use in the
disinfection process such as in the presence of high bather load
demand. Also, a decrease in total chlorine concentration has been
observed after the bathers exit the spa. Moreover, when the
chlorine cartridge is empty the chlorine bank begins to fall and
can be used as an indication that the cartridge needs to be
replaced. Typically one DCDMH cartridge filled with 100 grams of
DCDMH will last about 3-4 weeks depending on spa use. In view of
the aforementioned, the total chlorine level may be monitored in
the spa water to determine the quantity of chlorine that remains in
the cartridge while the free chlorine level may be monitored in the
spa water to determine disinfection potential.
[0032] FIG. 1 shows a graph of the measured dissolved silver
concentrations each week for the duration of the Spa Study 1. The
average dissolved silver concentration for Spa Study 1 was 16 ppb.
During week 10 the chlorine measured 160 ppb. The level of silver
that would be anticipated based on theoretical calculations of the
chlorine would be about 4.2 ppb, however, the actual measured
silver was 23 ppb. This is almost a 6-fold greater than would be
anticipated.
[0033] FIG. 2 shows a graph of dissolved silver concentrations each
week for Spa Study 2 as compared to the theoretical calculations
based on the chlorine measurement. The average dissolved silver
concentration for Spa Study 2 was 13 ppb. By the end of Spa Study 2
the measured level of silver was at least 3-fold greater than would
be anticipated based on theoretical calculations.
[0034] FIG. 3 shows a graph of the dissolved silver concentrations
each week for the duration of the Spa Study 3 as compared to the
theoretical calculations based on the chloride measurement. The
average dissolved silver concentration for Spa Study 3 was 11 ppb.
By the end of Spa Study 3 the measured level of silver was at least
5-fold greater than would be anticipated based on theoretical
calculations. It appears from Spa Study 3 that bathers do not have
an affect on dissolved silver concentrations. It is believed that
Spa Study 3 had the lowest average silver concentration because the
Spa Study 3 was run for seven (7) weeks compared to the testing
duration of twelve (12) and eight (18) weeks for Spa Study 1 and 2,
respectively. It is anticipated that if Spa Study 3 had been tested
longer in duration the average dissolved silver concentration would
have mostly likely been higher.
[0035] The above results of Spa Studies 1, 2, and 3, as shown in
FIGS. 1, 2, and 3 thus supports the finding that the combination of
other types of N-halohydantoin compounds such as DCDMH with a metal
ion donor such as silver chloride enhances a concentration of metal
ions in a body of water by retaining or increasing the solubility
of metal ions from other metal ion donors to retain the
antimicrobial activity of the metal ions in the body of water.
[0036] Per the inventor's above findings, it is anticipated that
N-halohydantoin compounds of the formula shown below can be used in
this invention.
##STR00002##
Where
[0037] X is either H, Cl, or Br; [0038] Y is either H, Cl, or Br;
[0039] R is an Alkyl group; and [0040] R1 is an Alkyl group.
[0041] R and R1 are independently selected from alkyl groups
(having from 1 to a plurality of carbons), and X and Y are
independently selected from bromine, chlorine and hydrogen. In
further regards to the above, as evidenced by the Inventor's use of
the Lonza DCDMH (Dantochlor.RTM.), which comprised a combination of
1,3-Dichloro-5,5 dimethylhydation,
1,3-Dichloro-5-ethyl-5-methylhydatoin, and
monochloro-5-methylhydation, a mixture of the derivatives of the
above N-halohydantoin compounds can also be used.
[0042] FIG. 4 is a table showing the free chlorine concentration
before and after two bathers used the spa for thirty (30) minutes
increments on sequential days. The first columns correspond to the
free chlorine level prior to the bathers entering the spa. The
second columns represent the free chlorine level after the bathers
exited the spa, and the third columns show the free chlorine
concentration two hours after the bather's have exited the spa.
Typically the next day after each bathing event the free chlorine
stabilized between 0.5 and 1.0 ppm free chlorine even if 2 hours
after spa use the free chlorine measured above 1.0 ppm. FIG. 4 also
shows that when the free chlorine level is below 0.5 ppm, and
bathers used the spa, the free chlorine goes up, instead of down.
This can be attributed to the above-discussed chlorine-hydantoin
bank, because as the demand for free chlorine goes up, the
hydantoin releases the second chlorine on the ring to add to
disinfection. Also the additional circulation from the jets of the
spa and/or increases in water temperature may cause more DCDMH to
dissolve into the spa water, and possibly increase the kinetics of
the reaction.
[0043] The above results of Spa Studies 1, 2, and 3 show that: (1)
spa water chlorine concentrations can be controlled when DCDMH is
dispensed from a cartridge; (2) at a fixed cartridge setting,
chlorine concentrations can be maintained at levels of 0.5 to 1.0
ppm and higher as needed; (3) concentrations of actual silver are 3
to 6-fold higher in spa water than would be anticipated by
theoretical calculations based on silver chloride solubility; (4)
that due to the unique chemistry of N-halohydantoins such as DCDMH,
total chlorine concentrations behave as a chlorine bank that is
readily available under conditions requiring high chlorine demand,
but without the risk of over chlorination; (5) that spa water
treated with N-halohydantoins such as DCDMH is as clear as, if not
clearer, then water treated with N-halohydantoins such as BCDMH;
and (6) that after spa water has been balanced according to the
saturation index, pH remains in a more neutral range (pH 7.4) as
compared to spa water treated with N-halohydantoins such as
BCDMH.
Apparatus
[0044] Referring to FIGS. 5 and 6, FIG. 5 shows an embodiment of an
apparatus of the present invention comprising a dispenser 10 having
a housing 11 containing a compartment 12 therein. Located in
compartment 12 is a source of a N-halohydantoin compound such as
DCDMH 13 and a bactericide comprising a silver ion donor such as
silver chloride 14. A set of openings 15 allows water access to
compartment 12 and to the source of DCDMH 13 and the silver
chloride 14.
[0045] FIG. 6 shows an alternative embodiment of an apparatus of
the present invention comprising a dispenser 16 having a first
housing 17 containing a compartment 18 and a second housing 19 with
a compartment 20 therein. Located in compartment 18 is a silver ion
donor such as silver chloride 21 and located in compartment 20 is a
source of a N-halohydantoin compound 22. A set of openings 23
allows water access to compartment 18 and to the silver chloride
21. Similarly, a set of openings 24 allows water access to
compartment 20 and the source of N-halohydantoin compound 22.
Although FIGS. 5 and 6 shows the use of the silver ion donor as
comprising silver chloride, other types of silver ion donors and
other alternative bactericides whose solubility can be changed in
the presence of N-halohydantoin compound can also be used such as
silver bromide.
[0046] In regards to the source of N-halohydantoin compound 13, 22,
FIG. 6 shows the source of N-halohydantoin compound 22 in particle
form with the aforementioned particles having an initial size that
is larger than the size of opening 23 to prevent the
N-halohydantoin compound particles from escaping through opening
23. FIG. 5 shows the source of N-halohydantoin compound 13 in
tablet form. Various types of material, including but not limited
to microcrystalline cellulose (MCC), may be used as a binder in the
formation of the N-halohydantoin compound tablets which are
tabletized with the metal ion donor so that both the
N-halohydantoin compound and the metal ion donor can be placed in
the body of fluid to be treated.
[0047] The present invention includes the step of placing the
dispenser 10, 16 containing both the source of N-halohydantoin
compound 13, 22 and the silver chloride 14, 21 in the body of water
such as a body of water support in a spa, hot tub or swimming pool
and allowing water to come into contact with the source of
N-halohydantoin compound 13, 22 and the silver chloride 14, 21 to
periodically release N-halohydantoin compound and silver ions into
the body of water. As the N-halohydantoin compound is released into
the body of water, the N-halohydantoin compound is carried to the
silver chloride 14, 21 and interacts with the silver chloride 14,
21 to increase the solubility of the silver thereby allowing for
the release of more silver ions into the body of water than the
silver chloride 14, 21 alone.
[0048] The present invention can also include a method of treating
a body of water to kill microorganisms by maintaining an effective
concentration biocides comprising the steps of: (1) adding a silver
salt 14, 21 to the body of water such as a body of water support in
a spa, hot tub or swimming pool; and (2) adding a concentration
N-halohydantoin compound 13, 22 to the body of water to interact
with the silver salt 14, 21 to maintain a silver ion concentration
effective to kill microorganisms. The aforementioned method can
also include the steps of (3) adding silver chloride 14, 21 to the
body of water; (4) adding silver bromide to the body of water; (5)
treating a body of recreational water for at least partial human
immersion therein; (6) placing a dispenser 10, 16 containing both
the silver salt 14, 21 and the N-halohydantoin compound 13, 22 in
the body of water and allowing water to come into contact with both
the silver salt 14, 21 and the N-halohydantoin compound 13, 22; (7)
adding silver chloride to the body of water on a carrier of
limestone; and (8) increasing the temperature of the body of water
to increase the dissolution of the N-halohydantoin compound 13, 22
in the body of water.
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