[0001] The present invention relates generally to a washing machine, and, more particularly,
to a washing machine equipped with a disinfecting liquid dispenser, and a method of
controlling the washing machine.
[0002] Disinfecting washing machines may be classified into disinfecting washing machines
using ozone and disinfecting washing machines using silver ions. Of these disinfecting
washing machines, disinfecting washing machines using silver ions are equipped with
disinfecting fluid dispensers that produce and supply a silver solution to disinfect
laundry through antibacterial and bactericidal actions of the silver solutions.
[0003] The silver solution is produced by forming silver ions (Ag
+) and dissolving them into water. The silver solution is used as an antibacterial
agent or a bactericide. It is reported that such a silver solution eliminates about
650 kinds of bacteria. In particular, the silver solution is characterized as not
inducing resistance, which is different from general antibiotics, and is safe because
the silver solution has no toxic effects on humans. Methods of manufacturing silver
solutions include an electrolysis method, a chemical resolution method, and a pulverization
method. Of these methods, the electrolysis method is most effective at dissolving
the silver ions into the water.
[0004] A disinfecting effect of the silver solution is determined based on a concentration
of the silver solution. That is, when the concentration of the silver solution is
excessively low, the disinfecting effect is reduced. In contrast, when the concentration
of the silver solution is excessively high, laundry may be discolored. Accordingly,
the concentration of the silver solution needs to be controlled, to provide a sufficient
disinfecting effect without discoloring the laundry. Further, to produce a silver
solution of an appropriate concentration, voltages applied to silver plates of a silver
ion generating device must be controlled within an appropriate range.
[0005] It is an aim of the present invention to provide a washing machine and a method of
controlling the washing machine, which can maintain a concentration of a silver solution
within a predetermined appropriate range, and ideally to provide a sufficient disinfecting
effect without discoloring laundry with the silver solution.
[0006] Other aims and/or advantages of the invention will be set forth in part in the description
which follows and, in part, will be obvious from the description, or may be learned
by practice of the invention.
[0007] According to the present invention there is provided an apparatus and method as set
forth in the appended claims. Preferred features of the invention will be apparent
from the dependent claims, and the description which follows.
[0008] In one aspect of the present invention there is provided a washing machine including
a disinfecting liquid dispenser to provide a disinfecting liquid to disinfect laundry,
a drive unit to generate first and second control voltages, and to output the first
and second control voltages to the disinfecting liquid dispenser to control a concentration
of the disinfecting liquid, a comparator unit to determine whether the concentration
of the disinfecting liquid falls within a predetermined range, and a control unit
to control the drive unit so that the concentration of the disinfecting liquid has
a value within the predetermined range.
[0009] In another aspect of the present invention there is provided a method of controlling
a washing machine, the washing machine having a disinfecting liquid dispenser to provide
a disinfecting liquid to disinfect laundry, and a drive unit to generate first and
second control voltages, and to output the first and second control voltages to the
disinfecting liquid dispenser to control a concentration of the disinfecting liquid,
the method including determining an amount of driving current using the first and
second control voltages, continuously generating the first and second control voltages
if the amount of driving current falls within a predetermined range, and restricting
an operation of the washing machine if the amount of driving current deviates from
the predetermined range.
[0010] For a better understanding of the invention, and to show how embodiments of the same
may be carried into effect, reference will now be made, by way of example, to the
accompanying diagrammatic drawings in which:
Figure 1 is a sectional view showing a washing machine, according to an embodiment
the present invention;
Figure 2 is a partial sectional view showing a disinfecting liquid dispenser of the
washing machine of Figure 1;
Figure 3 is a block diagram showing a silver solution concentration control device
of the washing machine of Figure 1;
Figure 4 is a circuit diagram showing a drive unit of the silver solution concentration
control unit of Figure 3;
Figures 5A to 5D are waveform diagrams of signals applied to the drive unit of Figure
4; and
Figure 6 is a flowchart showing a method of controlling a concentration of a silver
solution of the washing machine of Figure 2.
[0011] A washing machine and method of controlling the washing machine are described with
reference to Figures 1 to 6. Figure 1 is a sectional view showing the washing machine.
As is shown in Figure 1, a water tub 104 is disposed in a body casing 102 to contain
washing water. A washing tub 106 is disposed in the water tub 104. A pulsator 108
is positioned in a lower portion of an interior of the washing tub 106, and is rotated
in forward and reverse directions to create currents of washing water. A drive unit
110 is positioned under the water tub 104 to rotate the washing tub 106 and the pulsator
108. The drive unit 110 includes a drive motor 112 and a power transmission unit 114.
The drive motor 112 is rotated by power supplied thereto, and the power transmission
unit 114 serves to selectively transmit power generated by the drive motor to the
pulsator 108 and the washing tub 106. A belt 116 is wound around the drive motor 112
and the power transmission device 114 to mediate the transmission of power.
[0012] Figure 2 is a partial sectional view showing a disinfecting liquid dispenser 120
of the washing machine. As is depicted in Figure 2, when a washing course is selected
after power is supplied to the washing machine and laundry is put into the washing
machine, washing water is fed into an interior of a water tub 104. The washing water
fed into the water tub 104 dissolves a detergent while passing through a detergent
dispenser (not shown), and is supplied to the water tub 104 along with the dissolved
detergent.
[0013] If a user selects a disinfection washing course, an inlet valve 204 of the disinfecting
liquid dispenser 120 is opened and water is supplied to an interior of a storage container
122, at the same time that the washing water is fed to the water tub 104. When power
is applied to two silver plates 220 and 222 of the disinfecting liquid dispenser 120,
a silver disinfecting liquid is produced. This silver disinfecting liquid is supplied
to the interior of the washing tub 106 and disinfects the laundry.
[0014] The water supplied though an inlet 202 of the storage container 122 is halted to
stabilize a flowing speed and a flow thereof while filling a first space 210 of the
storage container 122. The water contained in the first space 210 overflows a first
partition 206 and flows into a second space 214. The water having passed through the
first space 210 and flowing into the second space 214 fills the second space 214 to
a water level corresponding to the height of a second partition 208. After the second
space 214 is filled with the water, the water overflows the second partition 208 into
a third space 224, and then is supplied to the interior of the water tub 104 through
an outlet 216 of the storage container 122. In this case, the water contained in the
second space 214 flows into the third space 224 while a certain amount of water is
contained in the second space 214. In this process, the silver disinfecting liquid
is produced through electrolysis in the water, and the produced disinfecting liquid
is supplied to the washing water 106 through the outlet 216. The process of producing
such disinfecting liquid is continuously carried out while the water is supplied to
the storage container 122.
[0015] Additionally, in the process of producing the disinfecting liquid, if the amount
of water supplied through the inlet 202 is large, water contained in the interior
of the storage container 122 flows into a drain pipe 118a through a bypass pipe 128,
so that water is maintained at an appropriate water level in the storage container
122, thereby enabling production of the disinfecting liquid at a certain concentration.
When the process of producing the disinfecting liquid is stopped, water supply to
the storage container 122 is stopped by the closing of the inlet value 204, and power
application to the silver plates 220 and 222 is stopped. At this time, water remaining
in the interior of the storage container 122 flows into the outlet 216 through remaining
water discharging holes 206a and 208a and is completely discharged from the storage
container 122.
[0016] After washing water including the disinfecting liquid fills the water tub 104, the
washing of the laundry is performed by the rotation of the pulsator 108 and bacteria
are killed by the disinfecting liquid in the process of washing the laundry.
[0017] The disinfecting liquid dispenser 120 carries out electrolysis in the water by alternately
applying positive and negative voltages to the two silver plates 220 and 222, thus
generating silver ions. In this case, an amount of silver ions, that is, the concentration
of a silver solution, is proportional to an amount of current flowing through the
two silver plates 220 and 222, and is also proportional to a magnitude of the voltages
applied to the two silver plates 220 and 222.
[0018] Figure 3 is a block diagram showing a silver solution concentration control device,
with which the washing machine is equipped. As is shown in Figure 3, a drive unit
302 allows silver solution to be produced by alternately applying positive and negative
voltages to the disinfecting liquid dispenser 120. A polarity of a voltage applied
from the drive unit 302 to the disinfecting liquid dispenser 120 is controlled by
first and second switching signals 316 and 318 output from a control unit 306 to the
drive unit 302.
[0019] An amount of current supplied to the disinfecting liquid dispenser is proportional
to the magnitude of the applied voltages, which is estimated based on a driving current
324 flowing through the drive unit 302. If an amount of the driving current 324 exceeds
a predetermined highest limit of a range that is required to produce a silver solution
of a concentration suitable for disinfection of laundry, the control unit 306 prevents
silver ions from being generated by stopping application of the first and second switching
signals 316 and 318. If the amount of the driving current 324 is reduced to less than
a predetermined lowest limit of the range, the control unit 306 takes an appropriate
protective measure.
[0020] Reduction of the driving current 324 is caused in situations in which water is not
supplied through the disinfecting liquid dispenser 120, or an amount of supplied water
is insufficient, and may be caused by poor attachment of the silver plates 202 and
222 or disconnection of a power line. Accordingly, if the driving current 324 of the
drive unit 302 is reduced to less than the lowest limit, the control unit 306 generates
an alarm to warn a user and temporarily stops operation of the washing machine.
[0021] If the amount of the driving current 324 detected by a current detecting unit 308
exceeds the highest limit, a first comparator 312 generates an excessive current signal
320 and outputs the excessive current signal 320 to the control unit 306. When the
first comparator 312 generates the excessive current signal 320, the control unit
306 stops generation of silver ions in the disinfecting liquid dispenser 120 by blocking
at least one of the first and second switching signals 316 and 318. When the generation
of silver ions is stopped while water is supplied to the disinfecting liquid dispenser
120, a concentration of silver ions of the disinfecting liquid is reduced.
[0022] If the amount of the driving current 324 detected by a current detecting unit 308
is less than a preset lowest limit, a second comparator 310 generates an insufficient
current signal 322 and outputs the insufficient current signal 322 to the control
unit 306. When the second comparator 310 generates the insufficient current signal
322, the control unit 306 generates an alarm to warn the user, and temporarily stops
the operation of the washing machine.
[0023] The highest and lowest limits of the driving current 324 applied by the first and
second first and second comparators 312 and 310 of the washing machine according to
the embodiment of the present invention are bases to provide a sufficient disinfecting
effect as well as to prevent laundry from being discolored by the silver solution.
For this purpose, in a development stage of the washing machine, an optimal concentration
of the silver solution to provide a sufficient disinfecting effect as well as to prevent
laundry from being contaminated with the silver solution is obtained through experiments.
The highest and lowest values of the driving current 324 required to realize the optimal
concentration of the silver solution are thus obtained and set, thereby not only preventing
laundry from being discolored by the silver solution, but also providing a sufficient
disinfecting effect.
[0024] A construction of the drive unit 302 that controls the concentration of the silver
solution contained in the disinfecting liquid dispenser 120 is described below with
reference to Figures 4 and 5A to 5D. Figure 4 is a circuit diagram of the drive unit
302 of the silver solution concentration control unit. As is shown in Figure 4, NPN
bipolar transistors 402 and 404 create a series circuit between a source voltage VCC
and a ground GND. NPN bipolar transistors 406 and 408 form another series circuit
in parallel with the NPN bipolar transistors 402 and 404.
[0025] The NPN bipolar transistors 402 and 408 are controlled by the first switching signal
316, whereas the NPN bipolar transistors 404 and 406 are controlled by the second
switching signal 318. A first control voltage 326 output between the NPN bipolar transistors
402 and 404 is applied to one of the two silver plates 220 and 222 of the disinfecting
liquid dispenser 120. A second control voltage 328 output between the NPN bipolar
transistors 406 and 408 is applied to the other silver plate. In Figure 4, an emitter
current of the NPN bipolar transistors 404 and 408 is the driving current 324 that
is an entire current flowing through the drive unit 302. As described in connection
with Figure 3, the driving current 324 is detected by the current detecting unit 308,
and is supplied to the first and second comparators 312 and 310.
[0026] Figures 5A to 5D are waveform diagrams of signals applied to the drive unit 302 of
the silver solution concentration control device of Figure 4. As is shown in Figures
5A to 5D, phases of the first and second switching signals 316 and 318, which are
input signals, are opposite to each other. A certain dead time t
d exists between transition points of the first and second switching signals 316 and
318. If there were no dead time t
d, and the first and second switching signals 316 and 318 made transitions at the same
time, a range in which the two signals 316 and 318 overlap each other would be created,
and the two silver plates 220 and 222 would be short-circuited. If the dead time t
d is set between the transition points of the first and second switching signals 316
and 318, the two silver plates 220 and 222 of the disinfecting liquid dispenser 120
are prevented from being short-circuited.
[0027] Like the first and second switching signals 316 and 318, the first and second control
signals 326 and 328, that are output signals, are opposite to each other. A phase
of the first control voltage 326 is identical with a phase of the first switching
signal 316, whereas a phase of the second control voltage 328 is identical with a
phase of the second switching signal 318.
[0028] An operation of controlling the concentration of the silver solution of the disinfecting
liquid dispenser 120 is described with reference to Figures 4 and 5A to 5D. In Figures
5A to 5D, when the first switching signal 316 is at a high level and the second switching
signal 318 is at a low level, only the NPN bipolar transistors 402 and 408 of Figure
4 are turned on, so that the source voltage VCC is applied to the ground GND through
the NPN bipolar transistor 402, the disinfecting liquid dispenser 120 and the NPN
bipolar transistor 408. In this case, voltages are applied to the two silver plates
220 and 222 of the disinfecting liquid dispenser 120; the first control voltage 326
has a positive polarity and the second control voltage 328 has a negative polarity.
[0029] When the first switching signal 316 is at a low level and the second switching signal
318 is at a high level as a result of a phase change, only the NPN bipolar transistors
406 and 404 of Figure 4 are turned on, so that the source voltage VCC is applied to
the ground GND through the NPN bipolar transistor 406, the disinfecting liquid dispenser
120 and the NPN bipolar transistor 404. In this case, voltages are applied to the
two silver plates 220 and 222 of the disinfecting liquid dispenser 120; the first
control voltage 326 has a negative polarity and the second control voltage 328 has
a positive polarity.
[0030] As described above, the polarities of the first and second control voltages 316 and
318 output from the drive unit 302 to the disinfecting liquid dispenser 120 are changed
by the first and second switching signals 316 and 318. Since the first and second
control voltages 326 and 328 are voltages that are applied to the two silver plates
of the disinfecting liquid dispenser 120, a silver solution is produced in the disinfecting
liquid dispenser 120 while the first and second control voltages 326 and 328 are applied.
[0031] Figure 6 is a flowchart showing a method 600 of controlling the concentration of
the silver solution of the washing machine. As is shown in Figure 6, when a disinfection
washing mode starts in operation 602, the first and second switching signals 316 and
318 are applied to generate the first and second control voltages 326 and 328 in operation
604. Next, it is determined whether the driving current 324 falls within a range between
the predetermined highest limit I
max and the predetermined lowest limit I
min by detecting the driving current 324 flowing through the drive unit 302, in operation
608, and comparing the driving current 324 with currents of the range using the first
and second comparators 320 and 322 in operation 610.
[0032] If the driving current 324 falls within the range between the highest limit I
max and the lowest limit I
min in operation 610, the first and second switching signals 316 and 318 are continuously
applied in operation 612, and a washing process is terminated after a time set for
the washing process elapses in operation 614.
[0033] If the driving current 324 exceeds the highest limit I
max in operation 616, the concentration of the silver solution is prevented from being
increased by blocking the first and second switching signals 316 and 318 in operation
618, and the method 600 returns to operation 610 to determine whether the driving
current 324 falls within the predetermined range.
[0034] If it is determined in operation 616 that the driving current 324 does not exceed
the highest limit I
max, then in operation 620, it is determined whether the driving current 324 is less
than the lowest limit I
min. If the driving current 324 is less than the lowest limit I
min in operation 620, an alarm is generated in operation 622 and operation of the washing
machine is stopped.
[0035] As described above, the control unit 306 of the washing machine determines whether
a concentration of a currently produced silver solution falls within an appropriate
range and controls the silver solution to have an appropriate concentration by monitoring
an amount of current flowing between the two silver plates 220 and 222 of the disinfecting
liquid dispenser 120.
[0036] As is apparent from the above description, the present invention provides the washing
machine and the method of controlling the same, which can maintain the concentration
of the silver solution within the appropriate range that is required to provide a
sufficient disinfecting effect as well as to prevent laundry from being discolored
by the silver solution, by controlling the magnitude of voltages 336 and 328 applied
to the silver plates 220 and 222 according to the concentration of the silver solution.
[0037] Although a few preferred embodiments have been shown and described, it will be appreciated
by those skilled in the art that various changes and modifications might be made without
departing from the scope of the invention, as defined in the appended claims.
[0038] Attention is directed to all papers and documents which are filed concurrently with
or previous to this specification in connection with this application and which are
open to public inspection with this specification, and the contents of all such papers
and documents are incorporated herein by reference.
[0039] All of the features disclosed in this specification (including any accompanying claims,
abstract and drawings), and/or all of the steps of any method or process so disclosed,
may be combined in any combination, except combinations where at least some of such
features and/or steps are mutually exclusive.
[0040] Each feature disclosed in this specification (including any accompanying claims,
abstract and drawings) may be replaced by alternative features serving the same, equivalent
or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated
otherwise, each feature disclosed is one example only of a generic series of equivalent
or similar features.
[0041] The invention is not restricted to the details of the foregoing embodiment(s). The
invention extends to any novel one, or any novel combination, of the features disclosed
in this specification (including any accompanying claims, abstract and drawings),
or to any novel one, or any novel combination, of the steps of any method or process
so disclosed.
1. A washing machine, comprising:
a disinfecting liquid dispenser (120) to provide a disinfecting liquid to disinfect
laundry;
a drive unit (302) to generate first and second control voltages (326,328), and to
output the first and second control voltages (326,328) to the disinfecting liquid
dispenser (120) to control a concentration of the disinfecting liquid;
a comparator unit (310,312) to determine whether the concentration of the disinfecting
liquid falls within a predetermined range; and
a control unit (306) to control the drive unit (302) so that the concentration of
the disinfecting liquid has a value within the predetermined range.
2. The washing machine as set forth in claim 1, wherein:
the disinfecting liquid dispenser (120) comprises at least two silver plates (220,222);
and
the disinfecting liquid is a silver solution that is produced through electrolysis
performed by applying the first and second control voltages (326,328) to the at least
two silver plates (220,222).
3. The washing machine as set forth in claim 2, wherein:
the concentration of the silver solution is determined by respective levels of the
first and second control voltages (326,328).
4. The washing machine as set forth in any preceding claim, further comprising:
a current detecting unit (308) to determine an amount of current supplied from the
drive unit (302) to the disinfecting liquid dispenser (120);
wherein the comparator unit (310,312) determines whether the concentration of
the disinfecting liquid falls within the predetermined range based on the determined
amount of current.
5. The washing machine as set forth in any preceding claim, wherein the comparator unit
(310,312) comprises:
a first comparator (312) to output a first current signal to the control unit (306)
if the amount of current is more than a highest limit of the predetermined range;
and
a second comparator (310) to output a second current signal to the control unit (306)
if the amount of current is less than a lowest limit of the predetermined range,
wherein the control unit (306) reduces the concentration of the disinfecting liquid
by controlling the drive unit (302) if the excessive current signal is generated,
and generates an alarm if the insufficient current signal is generated.
6. The washing machine as set forth in any preceding claim, wherein the drive unit (302)
comprises:
first and second switching circuits (402-408) that receive first and second switching
signals alternating between first and second levels and having opposite phases, and
respectively output the first and second control voltages (326,328), which have opposite
phases.
7. The washing machine as set forth in claim 6, wherein:
the first and second switching circuits (402-408) are alternately turned on by the
first and second switching signals, so that the first and second control voltages
(326,328) have phases and periods substantially identical with those of the first
and second switching signals.
8. A method of controlling a washing machine, the washing machine having a disinfecting
liquid dispenser (120) to provide a disinfecting liquid to disinfect laundry, and
a drive unit (302) to generate first and second control voltages (326,328), and to
output the first and second control voltages (326,328) to the disinfecting liquid
dispenser (120) to control a concentration of the disinfecting liquid, the method
comprising:
determining an amount of driving current using the first and second control voltages
(326,328);
continuously generating the first and second control voltages (326,328) if the amount
of driving current falls within a predetermined range; and
restricting an operation of the washing machine if the amount of driving current deviates
from the predetermined range.
9. The method as set forth in claim 8, wherein:
the generating of the first and second control voltages (326,328) is stopped if the
amount of driving current exceeds a highest limit of the predetermined range; and
an alarm is generated and the operation of the washing machine is stopped if the amount
of driving current is reduced to less than a lowest limit of the predetermined range.
10. An apparatus, comprising:
a disinfecting liquid dispenser (120) dispensing a disinfecting liquid to a washing
machine;
a driver (302) outputting first and second control voltages (326,328) to the disinfecting
liquid dispenser (120) to control a concentration of the disinfecting liquid;
a comparator (310,312) determining whether a concentration of the disinfecting liquid
is within a predetermined range; and
a controller (306), controlling the driver (302) outputting the first and second control
voltages (326,328) based on the determination of the comparator (310,312).
11. The apparatus according to claim 10, wherein:
the controller (306) outputs first and second switching signals to respectively control
the driver (302) outputting the first and second control voltages (326,328).
12. The apparatus according to claim 11, wherein:
the comparator (310,312) sends a first signal to the controller (306) if the concentration
of the disinfecting liquid exceeds the predetermined range; and
the comparator (310,312) sends a second signal to the controller (306) if the concentration
of the disinfecting liquid is below the predetermined range.
13. The apparatus according to claim 12, wherein the comparator (310,312) comprises:
a first comparator (312) sending the first signal; and
a second comparator (310) sending the second signal.
14. The apparatus according to claim 12 or 13, wherein:
when the controller (306) receives the first signal, the controller (306) outputs
the first and second switching signals to respectively reduce the first and second
control voltages (326,328); and
when the controller (306) receives the second signal, the controller (306) generates
an alarm.
15. The apparatus according to claim 14, wherein:
when the controller (306) receives the second signal, the controller (306) also shuts
off the apparatus.
16. The apparatus according to any of claims 10 to 15, further comprising:
a current detector determining an amount of current flowing through the driver (302),
wherein the comparator (310,312) determines whether the concentration of the disinfecting
liquid is within the predetermined range based on the determined amount of current.
17. The apparatus according to any of claims 10 to 16, wherein the disinfecting liquid
dispenser (120) comprises:
at least two metal plates (220,222);
wherein the first and second control voltages (326,328) are applied to the at
least two metal plates (220,222) to produce metal ions in the disinfecting liquid
through electrolysis.
18. The apparatus according to claim 17, wherein:
the at least two metal plates (220,222) are silver;
the metal ions are silver ions; and
the concentration of the disinfecting liquid is the concentration of silver in the
disinfecting liquid.
19. The apparatus according to claim 18, wherein:
when the concentration of silver in the disinfecting liquid is within the predetermined
range, the disinfecting liquid provides an antibacterial effect to an item being washed
in the washing machine without discoloring the item.
20. The apparatus according to claim 11, wherein the driver (302) comprises:
first and second switching circuits (402-408), respectively receiving the first and
second switching signals, wherein the first and second switching signals each alternate
between first and second levels, have opposite phases, and respectively output the
first and second control voltages (326,328) such that the first and second control
voltages (326,328) have opposite phases.
21. The apparatus according to claim 20, wherein:
the first and second switching circuits (402-408) are alternately turned on by the
first and second switching signals, so that the first and second control voltages
(326,328) have phases and periods respectively identical with those of the first and
second switching signals.
22. A method to control an apparatus including a driver (302) and a disinfecting liquid
dispenser (120), the method comprising:
outputting first and second control voltages (326,328) from the driver (302) to the
disinfecting liquid dispenser (120);
determining a magnitude of a driving current flowing through the driver (302);
determining whether the magnitude of the driving current is within a predetermined
range;
if the magnitude of the driving current is within the predetermined range, maintaining
the first and second control voltages (326,328) for a predetermined amount of time;
if the magnitude of the driving current is greater than the predetermined range, reducing
the first and second control voltages (326,328); and
if the magnitude of the driving current is less than the predetermined range, generating
an alarm.
23. A washing machine, comprising:
a disinfecting liquid dispenser (120); and
at least two silver plates (220,222), wherein the washing machine maintains a concentration
of a silver solution in an appropriate range to provide a sufficient disinfecting
effect and prevent laundry from being discolored, by controlling a magnitude of voltages
applied to the at least two silver plates (220,222) according to the concentration
of the silver solution.
24. A method, comprising:
controlling a magnitude of voltages applied to silver plates according to a concentration
of a silver solution, to maintain the concentration of the silver solution in an appropriate
range to provide a sufficient disinfecting effect and prevent laundry from being discolored.