TECHNICAL FIELD
[0001] The present invention relates to a rotatable drum type washing machine for washing
laundry such as clothes.
BACKGROUND ART
[0002] Conventionally, a rotatable drum type washing machine of this kind washes laundry
by operations shown below.
[0003] First, after laundry has been loaded into a rotatable drum, washing and/or rinsing
water is supplied from the outside of the washing machine through a water supply unit.
The supplied washing and/or rinsing water is poured into a vessel (for example water
tub) that houses the rotatable drum through a detergent case previously inserted with
a predetermined amount of detergent. After the washing and/or rinsing water has been
poured, the laundry is made sufficiently wet with the washing and/or rinsing water
while the rotatable drum is rotated at a low speed.
[0004] Next, the rotatable drum is rotated for a fixed time at a low rotational frequency
to such an extent that the laundry does not stick to the wall surface of the rotatable
drum. Therefore, the laundry wet with the washing and/or rinsing water is lifted to
the upper part of the rotatable drum by rotation of the rotatable drum, and the laundry
is then dropped from the upper part of the rotatable drum due to its deadweight. By
impact of the dropping, dirt is removed, to clean the laundry.
[0005] However, in the configuration of the above rotatable drum type washing machine, it
is difficult to get laundry, having been loaded into the rotatable drum, uniformly
wet especially when an amount of laundry is large. This has caused non-uniform cleaning
of the laundry, leading to significant deterioration in clearing performance.
[0006] In order to prevent the above non-uniform cleaning, the rotatable drum is first rotated
at a predetermined, relatively low rotational frequency to perform beat-washing after
pouring of the washing and/or rinsing water. The rotatable drum is then rotated at
a higher rotational frequency than the rotational frequency at the time of the beat-washing,
to perform squeeze-washing. Here, the predetermined rotational frequency is a rotational
frequency at which the washing and/or rinsing water in the laundry is discharged to
the outside of the rotatable drum by centrifugal force. At this time, a high rotational
frequency of the rotatable drum and the number of times the rotatable drum is rotated
at a high speed are controlled in accordance with an amount of cloths of the laundry
and a temperature of the washing and/or rinsing water, thereby providing the laundry
with a mechanical function necessary for cleaning, to efficiently agitate the laundry.
[0007] There has thus been disclosed a rotatable drum type washing machine which gets laundry
uniformly wet to clean the laundry (e.g., see PTL 1).
[0008] That is, the conventional rotatable drum type washing machine of PTL 1 controls rotation
of a rotatable drum based at least only on an amount of cloths of laundry and a temperature
of washing and/or rinsing water. Further, squeeze-washing and the like are performed
by making centrifugal force act on the laundry, to clean the laundry.
[0009] At this time, since an amount of dirt on the laundry and an amount of detergent inserted
are unknown, when the rotatable drum is rotated at a high speed to clean the laundry,
much unnecessary (more than necessary) foam may be generated in the rotatable drum.
It is to be noted that a factor of generation of unnecessarily much foam generally
lies in a case where there is a little dirt on the laundry, a case where the detergent
has been inserted in an amount not smaller than necessary for cleaning the dirt on
the laundry, or some other case.
[0010] However, since the rotatable drum type washing machine has not been configured to
control cleaning of laundry based on the state of foam generated in the rotatable
drum, there arises a problem of not being able to clean the laundry based on an optimum
foam state. This has resulted in occurrence of such a problem where, when too much
foam is generated, a load of a motor for rotating the rotatable drum increases due
to resistance of the foam, to increase power consumption.
[0011] There have then been disclosed rotatable drum type washing machines for detecting
generation of excessive foam in order to optimize washing based on the state of foam
(e.g., see PTL 2, PTL 3).
[0012] A rotatable drum type washing machine described in PTL 2 has a configuration to detect
generation of excessive foam by an electrode and spray cool water onto the foam to
remove the excessive foam.
[0013] Further, a rotatable drum type washing machine described in PTL 3 is a rotatable
drum type washing machine for controlling washing of laundry in such a manner as to
detect generation of excessive foam by means of a drive current of a motor and reduce
a rotational frequency of the rotatable drum (e.g., see PTL 3).
[0014] However, in the configurations of the conventional rotatable drum type washing machines,
control is performed by detecting only generation of excessive foam, thus causing
a problem of not being able to optimally clean the laundry based on the generated
state of the foam.
[0015] DE 10 2007 036041 A1 relates to a method for eliminating foam in a drum washing machine with a program
control for controlling a program sequence, one in a lye container rotatably mounted
drum, a water inlet system, one at the bottom of the solution container arranged liquor
drainage system with a lye pump, a drive motor for the drum and a sensor for determining
a foam level hS and/or a negative temporal gradients of the foam level (dhS/dt) a
in the tub located liquid-air mixture, wherein when the sensor is detected foam during
a spin-up of the drum, ie; a continuous or discontinuous increasing the rotational
speed of the drum, in continuously or intermittently switched liquor pump a small
amount of water is added continuously or batchwise.
DE 10 2007 036041 A1 also relates to a device suitable for carrying out this method drum washing machine.
[0016] EP 0 268 155 A2 describes a washing machine with a device for preventing the formation of foam. During
the spinning operation, foam is often produced in the lye container for the washing
drum after a spinning time of a few seconds from a mixture of water and washing agents
which is expelled from the material being spun, and this can sometimes lead to an
interruption of the work of the emptying pump. So that spinning can be carried out
as soon as possible after completion of the washing operation at the maximum possible
washing- drum speed of the material being washed or spun, without the danger of the
formation of foam in the lye container to prevent the further pumping away of the
washing lye, there is provided as a measuring device a pressure sensor, the output
signals of which are an indication of the foam formation during the spinning operation,
these output signals representing control variables for the drive motor of the washing
drum and therefore for the regulation of the spinning speed. There is also described
a program-controlled washing machine with a washing drum drivable in the washing and
spinning mode by means of a motor.
[0017] EP 0 740 010 A2 describes a washing method which can eliminate suds or foam created in the course
of washing by a washing machine and can effectively prevent the creation of foam,
thereby improving the washing efficiency of the washing machine. In the washing method,
a part of the washing liquid is continuously recirculated and sprayed during the washing
process while the washing liquid is partially drained at each predetermined time interval.
In the rinsing process, a part of the rinsing water is also continuously recirculated
and sprayed during the rinsing process while the rinsing water is partially drained
at each predetermined time interval.
Citation List
Patent Literature
SUMMARY OF THE INVENTION
[0019] The invention is defined by the subject-matter of independent claim 1. The dependent
claims are directed to advantageous embodiments.
ADVANTAGES OF THE INVENTION
[0020] Advantageously, a rotatable drum type washing machine includes: a rotatable drum
for housing laundry; a vessel for housing the rotatable drum; a motor for driving
the rotatable drum; a water supply unit for supplying washing and/or rinsing water
into the vessel; a circulator for circulating the washing and/or rinsing water in
the vessel into the rotatable drum; a foam detector for detecting an amount of foam;
and a controller for controlling at least one of the following steps a washing step,
a rinsing step and water removal step. The controller is configured to control so
as to rotate the rotatable drum at a predetermined rotational frequency and configured
to control a spraying of the washing and/or rinsing water by the circulator onto the
laundry in the rotatable drum based on the amount of foam detected by the foam detector.
[0021] Therefore, based on the amount of foam detected by the foam detector, the rotatable
drum is rotated at the predetermined rotational frequency, to discharge the washing
and/or rinsing water impregnated among fibers of the laundry by centrifugal force
together with dirt. Further, the washing and/or rinsing water is sprayed by the circulator
onto the laundry in the rotatable drum, thereby loading (infiltrating) the washing
and/or rinsing water into the fibers of the laundry. As a result, when there is much
dirt on the laundry, replacement of the washing and/or rinsing
water among the fibers of the laundry is promoted to accelerate a dirt removing effect
so as to enhance a cleaning effect.
[0022] Further, dirt attached to the detergent and to the washing and/or rinsing water mixed
with the detergent in the vicinity of the laundry can be peeled as much as necessary.
Therefore, unnecessary foaming at the time of washing is suppressed, and the cleaning
operation is performed as much as necessary. This can result in realization of a rotatable
drum type washing machine capable of reducing a wasteful operation and power consumption.
BRIEF DESCRIPTION OF DRAWINGS
[0023]
FIG. 1 is a principal-part sectional view of a rotatable drum type washing machine
in a first exemplary embodiment of the present invention.
FIG. 2 is a block diagram explaining control of the rotatable drum type washing machine
according to the same exemplary embodiment.
FIG. 3 is a time chart explaining an example of a control operation of the rotatable
drum type washing machine according to the same exemplary embodiment.
FIG. 4 is a view showing a state of laundry at the time of operating the rotatable
drum type washing machine according to the same exemplary embodiment.
FIG. 5 is a time chart explaining an example of an operation of a rotatable drum type
washing machine according to a second exemplary embodiment of the present invention.
FIG. 6 is a schematic constitutional view of a rotatable drum type washing machine
according to a third exemplary embodiment of the present invention.
FIG. 7 is a flowchart explaining a control operation of a washing step of the rotatable
drum type washing machine according to the same exemplary embodiment.
FIG. 8 is a diagram showing an example of an output of a transparency sensor in the
washing step of the rotatable drum type washing machine according to the same exemplary
embodiment.
FIG. 9A is a flowchart showing cleaning control of the rotatable drum type washing
machine in a fourth exemplary embodiment of the present invention.
FIG. 9B is a flowchart showing cleaning control of the rotatable drum type washing
machine in the same exemplary embodiment.
DESCRIPTION OF EMBODIMENTS
[0024] Embodiments of the present invention will be described below with reference to the
drawings. It is to be noted that the present invention is not restricted by the present
exemplary embodiments.
FIRST EXEMPLARY EMBODIMENT
[0025] FIG. 1 is a principal-part sectional view of a rotatable drum type washing machine
in a first exemplary embodiment of the present invention. FIG. 2 is a block diagram
explaining control of the rotatable drum type washing machine according to the same
exemplary embodiment.
[0026] As shown in FIG. 1, the rotatable drum type washing machine of the present embodiment
at least includes: vessel 2 (for example water tub) shakably disposed inside enclosure
1; rotatable drum 3 rotatably housed in vessel 2; motor 7 for rotatably driving rotatable
drum 3; circulation channel 16 provided with circulation pump 17; controller 22; and
foam detectors 27, 28. In enclosure 1, vessel 2 is disposed in the state of being
inclined forward and elastically supported via an underslung spring (not shown) and
a dumper (not shown), to store washing and/or rinsing water.
[0027] Rotatable drum 3 is formed in a bottom-closed cylinder shape for housing laundry
and rotatably provided in vessel 2. A peripheral side wall surface of rotatable drum
3 is provided with a plurality of baffles 4 and a large number of small holes 5 communicating
with the inside of vessel 2, and the front surface side of rotatable drum 3 is provided
with opening 6 through which laundry is put in and taken out.
[0028] Motor 7 is fixed for example to the outer-peripheral lower part of vessel 2, and
rotationally drives rotatable drum 3 via belt 8 and pulley 9. Water supply valve 10
is subjected to opening/closing-control by controller 22, and by opening water supply
valve 10, washing and/or rinsing water is supplied into vessel 2 through detergent
case 12 which is provided in water supply channel 11 and into which a detergent is
inserted.
[0029] Further, on the bottom in vessel 2, water tank unit 13 for storing the washing and/or
rinsing water is provided, and in water tank unit 13, heater 14 is disposed in substantially
parallel (or parallel) with the water surface of the washing and/or rinsing water
stored in vessel 2. Then, heater 14 heats the washing and/or rinsing water stored
in water tank unit 13 to a predetermined temperature (e.g., 30 to 40°C) suitable for
washing. At this time, the temperature of the washing and/or rinsing water in water
tank unit 13 is detected by temperature detector 15 such as a thermister. For example,
when there is no need for promoting foaming of the detergent by heating the washing
and/or rinsing water, water tank unit 13 and heater 14 may not particularly be provided
in vessel 2.
[0030] Moreover, the washing and/or rinsing water stored in water tank unit 13 in vessel
2 is circulated in rotatable drum 3 by circulation pump 17 as a circulator provided
in circulation channel 16. At this time, one end of circulation channel 16 communicates
with intake 18 which is provided on the bottom of water tank unit 13 and sucks in
the washing and/or rinsing water, and the other end thereof communicates with outlet
19 which is provided in the upper part of opening 6 on the front surface side of rotatable
drum 3. Then, the washing and/or rinsing water sucked in from intake 18 is spewed
out inward rotatable drum 3 from outlet 19 and then circulated by circulation pump
17 provided in circulation channel 16.
[0031] Further, switch valve 20 is provided downstream of circulation pump 17 in circulation
channel 16. Switch valve 20 selectively switches between circulation channel 16 that
communicates with outlet 19 and drainage channel 21 that discharges the washing and/or
rinsing water to the outside of the machine. Specifically, at the time of washing
and rinsing, switch valve 20 is switched to the circulation channel 16 side, to spew
out the washing and/or rinsing water in water tank unit 13 from outlet 19 toward the
laundry in rotatable drum 3. On the other hand, after washing and rinsing, switch
valve 20 is switched to the drainage channel 21 side, to discharge the washing and/or
rinsing water in vessel 2 to the outside of the rotatable drum type washing machine.
[0032] Moreover, controller 22 is provided in enclosure 1, and as shown in FIG. 2, for example,
operations of motor 7, water supply valve 10, heater 14, circulation pump 17, switch
valve 20 and the like are controlled based on detection information (detection signals)
of temperature detector 15, weight detector 25, water-level detector 26 and foam detector
27. Accordingly, a series of steps such as a washing step, a rinsing step and a water
removal step is controlled by controller 22.
[0033] Further, as shown in FIG. 1, at least two foam detectors are provided at positions
opposed to the rotatable drum on the inside of vessel 2. One foam detector 27 is provided
at a lower position than the center of rotational shaft 3A of rotatable drum 3 on
the inside of the front surface in vessel 2. It is to be noted that the reason for
installing foam detector 27 at this position is to promptly detect generated foam.
If foam detector 27 is installed at a higher position than the center of rotational
shaft 3A of rotatable drum 3, detection of the amount of foam is delayed, and hence
the inside of rotatable drum 3 is filled with foam due to generation of excessive
foam. At this time, an operation such as a defoaming step or water drainage is performed
for removing the filling foam. Thereat, in order to avoid those operations, foam detector
27 is provided at the lower position than the center of rotational shaft 3A of rotatable
drum 3.
[0034] The other foam detector 28 is provided, for example, at a position opposed to the
outer-peripheral bottom surface of rotatable drum 3 in the vicinity of the upper part
of the rear-surface (motor) side in vessel 2. It is to be noted that foam detectors
27, 28 of the present exemplary embodiment are, for example, configured by an electrode
sensor made up of a pair of electrodes, and an amount of foam is detected by controller
22 by means of a current change at the time of the foam coming into contact between
the pair of electrodes. It is thereby possible to detect generation of foam up to
a predetermined height at which foam detector 27 is provided in rotatable drum 3.
[0035] The rotatable drum type washing machine of the present exemplary embodiment is configured
as described above.
[0036] An operation and function of the rotatable drum type washing machine will be described
below with reference to FIGS. 3 and 4, while referring to FIGS. 1 and 2.
[0037] FIG. 3 is a time chart explaining an example of a control operation of the rotatable
drum type washing machine according to the first exemplary embodiment. FIG. 4 is a
view showing a state of laundry at the time of operating the rotatable drum type washing
machine according to the same exemplary embodiment.
[0038] First, door 23 provided openably/closably on the front surface side of enclosure
1 shown in FIG. 1 is opened, and laundry is loaded into rotatable drum 3 from opening
6.
[0039] Next, a power supply switch (not shown) of operator 24 provided on the top surface
of enclosure 1 is turned on, and a start switch (not shown) is operated, to start
an operation of the rotatable drum type washing machine.
[0040] As shown in FIG. 3, controller 22 then detects an amount of loaded laundry by weight
detector 25 shown in FIG. 2, to open water supply valve 10 and start supply of water
into vessel 2 through detergent case 12, while rotatably driving rotatable drum 3
by motor 7 to be rotated forwardly, backwardly and the like at 50 rpm, for example.
It is to be noted that an amount of water supplied is previously set in accordance
with an amount of loaded cloths, is the amount being detected by weight detector 25.
Thereby, washing and/or rinsing water is supplied into vessel 2 together with a detergent
inserted into detergent case 12. When water-level detector 26 detects the previously
set amount of washing and/or rinsing water supplied, controller 22 closes water supply
valve 10 to halt supply of the washing and/or rinsing water.
[0041] Next, the washing step is performed.
[0042] In the washing step, as shown in FIG. 3, rotatable drum 3 is driven by motor 7 to
be forwardly and backwardly rotated at 50 rpm, for example. Hence the so-called beat-washing
is performed in which the laundry in rotatable drum 3 is lifted by baffles 4 and dropped
from above onto the water surface of the washing and/or rinsing water in rotatable
drum 3.
[0043] It should be noted that, when the temperature of the supplied washing and/or rinsing
water is low or hot water is used for washing, heater 14 is turned on, to heat the
washing and/or rinsing water in water tank unit 13 to a temperature suitable for washing,
e.g., 30 to 40°C. This is preferable since, when cleaning performance deteriorates,
for example at the time of a low temperature of not higher than 10°C, the cleaning
effect can be enhanced by heating the washing and/or rinsing water.
[0044] At this time, the temperature of the washing and/or rinsing water heated by heater
14 is detected by temperature detector 15 such as a thermister provided on the outer
bottom of water tank unit 13. Controller 22 then controls a current carrying amount
of heater 14, or the like, such that the temperature of the washing and/or rinsing
water becomes the previously set temperature.
[0045] Subsequently, controller 22 switches switch valve 20 to the circulation channel 16
side, and drives circulation pump 17 at a previously set rotational frequency, to
circulate a predetermined amount of washing and/or rinsing water in rotatable drum
3. Thereby, the washing and/or rinsing water heated in water tank unit 13 is spewed
out from outlet 19 and impregnated into the laundry that is agitated and beat-washed
in rotatable drum 3. As a result, it is possible to promote dissolution of the detergent
into the washing and/or rinsing water, while strengthening the function of separating
dirt from clothes such as laundry, so as to enhance the clearing effect.
[0046] At this time, when the washing and/or rinsing water in water tank unit 13 is circulated
by circulation pump 17 into rotatable drum 3, a water level in vessel 2 is lowered.
For this reason, there occurs a case where the temperature of water tank unit 13 detected
by temperature detector 15 exceeds a predetermined temperature (e.g. 70°C) due to
lowering of the water level. In that case, controller 22 reduces the rotational frequency
of circulation pump 17 to decrease an amount of washing and/or rinsing water circulated,
to recover the water level in vessel 2.
[0047] Since the temperature of water tank unit 13 decreases with rise in water level in
vessel 2, controller 22 controls heater 14 such that the temperature of washing and/or
rinsing water in water tank unit 13 becomes a re-set temperature. Therefore, heater
14 is submerged into the risen washing and/or rinsing water, and controller 22 stably
keeps the temperature of the washing and/or rinsing water in water tank unit 13 at
the set temperature.
[0048] Hence the rotational frequency of circulation pump 17 and the like are controlled
based on the temperature detected by temperature detector 15, thereby allowing heater
14 to be kept in the state of capable of heating the washing and/or rinsing water
without being exposed on the water surface of the washing and/or rinsing water. Accordingly,
the washing and/or rinsing water can be circulated by circulation pump 17 and supplied
from outlet 19 into rotatable drum 3, while being heated to the optimum temperature.
[0049] Further, the washing and/or rinsing water in vessel 2 is rolled up and agitated by
rotational driving of rotatable drum 3, to generate foam, the washing and/or rinsing
water containing the detergent. When foam is excessively generated in vessel 2, it
is detected by foam detector 27 disposed at a lower position than the center of rotational
shaft 3A of rotatable drum 3. This can prevent a delay in detecting generated foam,
while obviating filling of the inside of rotatable drum 3 with foam, to avoid the
steps such as the defoaming step, the water drainage and the like. This can result
in efficient washing of laundry.
[0050] On the other hand, foam detector 28 provided in the upper part of the rear surface
side in vessel 2 detects generated foam when the foam is not detected by foam detector
27 and generated in a large amount up to the upper portion in vessel 2. This prevents
the generated foam from reversely flowing into the detergent case and being leaked
to the outside of the rotatable drum type washing machine.
[0051] At this time, as shown in FIG. 3, foam detectors 27, 28 each detect an amount of
foam generated in vessel 2 at the time when the washing and/or rinsing water containing
detergent is agitated by rotation of rotatable drum 3 after closing water supply valve
10 and completing supply of the washing and/or rinsing water. It is to be noted that
foam detectors 27, 28 each include for example the electrode sensor and detects a
current generated by foam coming into contact with the electrode sensor. A value of
the detected current is then measured, to judge generation of foam and an amount of
foam.
[0052] There will be described below a method for controlling rotatable drum type washing
based on a result of detection by the foam detector of the present exemplary embodiment.
[0053] First, as shown in FIG. 3, controller 22 forwardly and backwardly rotates rotatable
drum 3 at 50 rpm for a predetermined time to dissolve the detergent into the washing
and/or rinsing water, and thereafter turns on foam detector 27 for a predetermined
time to detect an amount of foam in vessel 2.
[0054] Generally, an appropriate amount of detergent is inserted into washing and/or rinsing
water set in accordance with an amount of laundry, and dissolved into the washing
and/or rinsing water. The dissolved detergent is foamed by rotation of rotatable drum
3 and the like so as to be activated, thus enhancing performance of removing dirt
on the laundry. However, when there is much dirt on the laundry, a little foam is
generated, to decrease the degree of activation of the detergent.
[0055] That is, when the foam generated in vessel 2 does not reach foam detector 27 and
the foam is thus not detected, namely when the amount of foam is determined to be
small, there is judged to be much dirt on the laundry in rotatable drum 3.
[0056] Thereat, when there is judged to be much dirt on the laundry, controller 22 controls
a rotational frequency of motor 7, and increases the rotational frequency of rotatable
drum 3 up to 150 to 200 rpm, to drive rotatable drum 3 to be rotated at high speed.
At this time, the laundry is attached to the inner surface of rotatable drum 3 by
high-speed rotation of rotatable drum 3. Hence the washing and/or rinsing water impregnated
among the fibers of the laundry is discharged by centrifugal force together with dirt.
Simultaneously, as shown in FIG. 3, circulation pump 17 as the circulator is turned
on, to circulate the washing and/or rinsing water in water tank unit 13 into rotatable
drum 3 and spray it onto the laundry in a shower form, for example.
[0057] Accordingly, as shown in FIG. 4, for example when rotatable drum 3 is rotated in
a direction of an arrow BB, laundry 33 is rotated by centrifugal force in such a state
as to stick to the inner surface of rotatable drum 3. At this time, the washing and/or
rinsing water is exchanged frequently among fibers of laundry 33. This results in
constant loading of new washing and/or rinsing water into the fibers of laundry 33,
thus allowing enhancement of the clearing effect of laundry 33. Further, the washing
and/or rinsing water can be sprayed onto the laundry by simultaneous circulation of
the washing and/or rinsing water in rotatable drum 3, thus accelerating replacement
of the washing and/or rinsing water among fibers of laundry 33. This can result in
further enhancement of the cleaning effect of the laundry.
[0058] In the above manner, the amount of foam in vessel 2 is detected to control the rotational
frequency of the rotatable drum, thereby executing the washing step.
[0059] The rinsing step is then started after completion of the washing step. Also in the
rinsing step, similarly, switch valve 20 is first switched to the drainage channel
21 side, to discharge the washing and/or rinsing water in vessel 2, and switch valve
20 is then switched to the circulation channel 16 side. Subsequently, water supply
valve 10 is opened and water supply is started from water supply channel 11 through
detergent case 12, and a predetermined amount of rinsing water is supplied into vessel
2.
[0060] Next, when water-level detector 26 detects a previously set predetermined water level,
controller 22 closes water supply valve 10 to halt supply of the rinsing water, and
rotationally drives motor 7. At this time, in the rinsing step, rotatable drum 3 is
driven by motor 7 to be forwardly and backwardly rotated at 50 rpm, and the laundry
in rotatable drum 3 is lifted and dropped onto the surface of the rinsing water.
[0061] Also in the rinsing step, similarly to the washing step, heater 14 provided in water
tank unit 13 of vessel 2 may be turned on to heat the rinsing water in vessel 2 so
as to perform rinsing. Further, also in the rinsing step, switch valve 20 may be switched
to the circulation channel 16 side to operate circulation pump 17 and circulate the
rinsing water into rotatable drum 3. Hence a detergent component and remaining dirt
are quickly removed from laundry such as clothes, thereby allowing enhancement of
the rinsing effect.
[0062] As described above, according to the present exemplary embodiment, the rotatable
drum is rotated at a predetermined rotational frequency based on the amount of foam
detected by the foam detector and the washing and/or rinsing water is sprayed by the
circulator onto the laundry in the rotatable drum, whereby it is possible to frequently
exchange the washing and/or rinsing water among the fibers of the laundry by centrifugal
force. Hence new washing and/or rinsing water can be constantly loaded into the fibers
of the laundry, and simultaneously, the washing and/or rinsing water can be circulated
in rotatable drum 3, to spray (scatter) the washing and/or rinsing water onto the
laundry. As a result, replacement of the washing and/or rinsing water among the fibers
of the laundry is accelerated, thereby allowing enhancement of the cleaning effect.
SECOND EXEMPLARY EMBODIMENT
[0063] A rotatable drum type washing machine in a second exemplary embodiment of the present
invention will be described below with reference to FIG. 5.
[0064] FIG. 5 is a time chart explaining an example of an operation of the rotatable drum
type washing machine according to the second exemplary embodiment of the present invention.
[0065] That is, as shown in FIG. 5, the rotatable drum type washing machine of the present
exemplary embodiment is different from the rotatable drum type washing machine of
the first exemplary embodiment in that upon rotating the rotatable drum at a predetermined
rotational frequency at which the laundry sticks to the inner surface of the rotatable
drum, at the start of the washing step, the washing and/or rinsing water is supplied
and thereafter an amount of foam by foam detector 27 is detected. The other configurations
and operations are the same as those in the first exemplary embodiment, and hence
specific descriptions thereof may be omitted.
[0066] Accordingly, the washing step different from that in the first exemplary embodiment
will be described below with reference to FIG. 5, while referring to FIG. 1.
[0067] As shown in FIG. 5, first at the start of the washing step, the rotational frequency
of rotatable drum 3 is increased by motor 7 up to 150 to 200 rpm, for example, and
that rotational frequency is kept. At this time, since vessel 2 has not been supplied
with the washing and/or rinsing water, the laundry loaded in vessel 2 (for example
water tub) is in a dry state. Accordingly, even when rotatable drum 3 is rotated at
a high speed, the laundry in rotatable drum 3 tends not to get unbalanced and there
is a little vibration in rotatable drum 3 due to eccentricity. Hence it is possible
to smoothly increase the rotational frequency of rotatable drum 3 up to a predetermined
rotational frequency.
[0068] After the rotational frequency of rotatable drum 3 has been increased up to 150 to
200 rpm and the rotation of rotatable drum 3 has been stabilized, water supply valve
10 is opened and a predetermined amount of washing and/or rinsing water is supplied
into vessel 2. The washing and/or rinsing water supplied into vessel 2 is gradually
impregnated into the laundry that is rotated in the state of sticking to the inner
surface of rotatable drum 3. For this reason, rotatable drum 3 can keep high-speed
rotation in a stable state without getting the laundry unbalanced in rotatable drum
3.
[0069] The washing and/or rinsing water supplied into vessel 2 is agitated by high-speed
rotation of rotatable drum 3, thereby dissolving the detergent contained in the washing
and/or rinsing water while foam is generated
[0070] Then, with the lapse of agitating time, the foam generated in vessel 2 rises in rotatable
drum 3 as its amount increases, and reaches foam detector 27 to be detected thereby.
[0071] At this time, the washing and/or rinsing water is supplied into vessel 2 in the state
of rotatable drum 3 being rotated at a high speed until time T1 at which the predetermined
amount of washing and/or rinsing water is supplied. During this period, the washing
and/or rinsing water containing the detergent is sufficiently agitated and foam in
accordance with dirt is generated.
[0072] Then, at the time when supply of the washing and/or rinsing water is completed after
the lapse of time T1 from the start of supply of the water and the washing and/or
rinsing water containing the detergent has been sufficiently agitated, the foam is
detected by foam detector 27. At this time, when the foam does not reach foam detector
27 and is not detected, namely when the amount of foam is small, there can be judged
to be much dirt on the laundry in rotatable drum 3.
[0073] Then, when there is judged to be much dirt on the laundry, controller 22 keeps the
rotational frequency of rotatable drum 3 at 150 to 200 rpm, to rotate the rotatable
drum at a rotational frequency at which the laundry sticks to the inner surface of
rotatable drum 3. Hence the washing and/or rinsing water impregnated among the fibers
of the laundry is discharged by centrifugal force together with dirt.
[0074] Simultaneously, controller 22 drives circulation pump 17 as the circulator, to circulate
the washing and/or rinsing water and spray it onto the laundry in rotatable drum 3.
Hence it is possible to effectively load the washing and/or rinsing water into the
fibers of the laundry. That is, when there is much dirt on the laundry, the washing
and/or rinsing water is actively replaced among the fibers of the laundry to accelerate
removal of the dirt, thereby allowing enhancement of the clearing effect.
[0075] According to the present exemplary embodiment, the rotatable drum is rotated at a
high speed from the start of the washing step, to sufficiently roll up and agitate
the washing and/or rinsing water in the vessel, and hence it is possible to promote
dissolution of the detergent and generation of foam. This can result in accurate detection
of the amount of foam.
THIRD EXEMPLARY EMBODIMENT
[0076] A rotatable drum type washing machine in a third exemplary embodiment of the present
invention will be described below with reference to FIG. 6.
[0077] FIG. 6 is a schematic constitutional view of the rotatable drum type washing machine
according to the third exemplary embodiment of the present invention. It is to be
noted that in the third exemplary embodiment, a description will be given using as
an example a different type of rotatable drum type washing machine from the rotatable
drum type washing machine of the first exemplary embodiment, but basic configurations
and operations are the same as those in the first exemplary embodiment.
[0078] That is, as shown in FIG. 6, the rotatable drum type washing machine of the present
exemplary embodiment is different from the rotatable drum type washing machine of
the first exemplary embodiment in that a transparency sensor for detecting a transparency
(turbidity) of washing and/or rinsing water is as the foam detector, the heater is
not provided, and the like. Since the method for control by detecting the amount of
foam in the rotatable drum by the foam detector will thus be different, an exemplary
embodiment will be provided and described below. As shown in FIG. 6, the rotatable
drum type washing machine of the present exemplary embodiment at least includes: vessel
2 (for example water tub) shakably disposed inside enclosure 1; rotatable drum 3 rotatably
housed in vessel 2; motor 7 for rotatably driving rotatable drum 3; circulation channel
16 provided with circulation pump 17; controller 22; and foam detector 32. Rotatable
drum 3 is disposed as inclined downward from a horizontal direction to a rear surface
direction. Further, rotatable drum 3 is connected with rotational shaft 3A of motor
7 provided on the rear surface of rotatable drum 3, and rotationally driven by rotation
of motor 7 through rotational shaft 3A. The peripheral side wall surface of rotatable
drum 3 is provided with a large number of small holes (not shown), and rotatable drum
3 functions as a water removal vessel and a drying vessel as well as a washing vessel.
[0079] Further, intake 18 is provided in the vicinity of the lowest part of vessel 2, and
communicates with circulation channel 16. Then, as shown in arrows in the figure,
washing and/or rinsing water taken from intake 18 by circulation pump 17 provided
in circulation channel 16 is circulated as spewed out in the shower form from outlet
30, which is provided for example in the lower part of the front surface side of rotatable
drum 3, into rotatable drum 3 through circulation channel 16. Therefore, circulation
of the washing and/or rinsing water through circulation channel 16 can be performed
only by control of circulation pump 17. As a result, the washing and/or rinsing water
can be circulated regardless of cleaning control which is to control the detergency,
such as a water flow of the washing and/or rinsing water in rotatable drum 3 which
is generated by rotation of rotatable drum 3.
[0080] At this time, foreign matters such as fibers of the laundry and hair included in
the washing and/or rinsing water as circulation water at the time of circulation are
removed by installing filter 31 between intake 18 and circulation pump 17 in circulation
channel 16. This can obviate clogging of circulation pump 17 and drainage channel
21.
[0081] Further, the transparency sensor that functions as foam detector 32 is provided upstream
of filter 31 in circulation channel 16. Transparency sensor is configured by a light-emitting
element such as an LED (Light Emitting Diode) and a light-receiving element such as
a photo transistor which are provided as opposed to each other. At this time, at least
a portion of circulation channel 16 located between the light-emitting element and
the light-receiving element of the transparency sensor is configured by a translucent
material.
[0082] Then, light emitted from the light-emitting element of the transparency sensor is
transmitted through the washing and/or rinsing water flowing through circulation channel
16 and received by the light-receiving element. An amount of light received is converted
into a voltage and then outputted to controller 22. Thereby, an amount of foam is
detected by the turbidity of the washing and/or rinsing water. Further, the turbidity
is found from the output voltage of the transparency sensor.
[0083] Moreover, switch valve 20 is provided for example between intake 18 and circulation
pump 17, and connected to drainage channel 21 located downstream of switch valve 20.
[0084] Furthermore, water-level detector 26 is provided in the vicinity of intake 18 of
vessel 2 which is impregnated (submerged) into the washing and/or rinsing water immediately
after its supply, and detects a water level of the water supplied into vessel 2 and
rotatable drum 3. Water-level detector 26 is configured for example by a diaphragm
or the like, and detects pressure applied to the diaphragm as a transformation of
the film, to detect the water level. It is to be noted that an amount of diaphragm
transformed in water-level detector 26 is detected for example by a change in capacitance
or a distortion gauge.
[0085] Further, water supply inlet 29 is connected to an external faucet through a hose
(not shown) or the like, and sequentially supplies washing and/or rinsing water and
rinsing water into vessel 2 and rotatable drum 3 by opening/closing of water supply
valve 10.
[0086] Moreover, controller 22 is, configured for example by a microcomputer or the like,
and when a water level detection signal of water-level detector 26 is inputted, opening/closing
of switch valve 20 and water supply valve 10, motor 7 and circulation pump 17 are
controlled, to control all of the washing step.
[0087] Furthermore, controller 22 converts the output voltage of the light-receiving element
constituting the transparency sensor as foam detector 32 into a transparency of the
washing and/or rinsing water, to perform an input step. At this time, the higher the
transparency is, namely the smaller the amount of foam is, the lower the output voltage
of the light-receiving element becomes. On the other hand, when the amount of foam
of the washing and/or rinsing water passing through circulation channel 16 increases,
the transparency decreases, and hence the output voltage of the light-receiving element
increases. That is, the amount of foam of the washing and/or rinsing water can be
detected by the output voltage of the transparency sensor which is outputted based
on the transparency of the washing and/or rinsing water.
[0088] Further, controller 22 also has a function of a cloth-amount detector by detecting
a current signal flowing through motor 7 that rotates rotatable drum 3. Thereby, a
weight of rotatable drum 3, namely a weight of laundry loaded into rotatable drum
3 is determined, to adjust an amount of water, washing time and the like to the optimum.
[0089] An operation of the rotatable drum type washing machine according to the present
exemplary embodiment will be described below with reference to FIG. 7.
[0090] FIG. 7 is a flowchart explaining the control operation of the washing step of the
rotatable drum type washing machine according to the third exemplary embodiment of
the present invention.
[0091] First, when laundry is loaded into the rotatable drum and washing is started, controller
22 detects an amount of laundry by the cloth-amount detector (Step S1). In addition,
as described above, the cloth-amount detector detects an amount of cloths based on
at least one piece of information concerning the motor operation, such as a magnitude
of a load current signal of motor 7, changes in current amount and rotational angle
at the time of rotating rotatable drum 3 together with the laundry.
[0092] Next, controller 22 decides a basic amount of washing and/or rinsing water to be
supplied based on the amount of laundry detected by the cloth-amount detector, the
washing and/or rinsing water being supplied into vessel 2. For example, when the amount
of laundry is determined as "small", controller 22 sets WL1 (Water Level 1) of a "low"
water level as a set water level. When the amount of laundry is determined as "medium",
controller 22 sets WL2 of a "medium" water level as the set water level. Further,
when the amount of laundry is determined as "large", controller 22 sets WL3 of a "high"
water level as the set water level (Step S2).
[0093] Next, controller 22 opens water supply valve 10 (Step S3), and supplies the washing
and/or rinsing water into vessel 2 and rotatable drum 3 until the water reaches the
set water level (Step S4). When the washing and/or rinsing water does not reach the
set water level (NO in Step S4), the detection operation is repeated until the washing
and/or rinsing water reaches the set water level. At this time, controller 22 drives
circulation pump 17 during supply of the washing and/or rinsing water, and circulates
the washing and/or rinsing water supplied as circulation water together with the detergent
from outlet 30 into vessel 2 through circulation channel 16, to promote dissolution
of the detergent into the washing and/or rinsing water. It is to be noted that, when
the washing and/or rinsing water is spewed out from outlet 30 into rotatable drum
3, clothes as laundry absorb the washing and/or rinsing water before the detergent
is dissolved into the washing and/or rinsing water. Thereat, the rotational frequency
of circulation pump 17 is set to be weak (low), to control such that much washing
and/or rinsing water is not spewed out into rotatable drum 3.
[0094] Next, when water-level detector 26 detects that the set water level has been reached
(YES in Step S4), controller 22 closes water supply valve 10 (Step S5).
[0095] A water supply step S1A is executed by Steps S1 to S5 described above.
[0096] Next, controller 22 starts a first low-speed agitating step for rotationally driving
rotatable drum 3 at a predetermined rotational frequency (Step S6). It should be noted
that the first low-speed agitating step is the agitating operation of lifting the
laundry by the baffles or the like in rotatable drum 3 and dropping the laundry from
the upper part of rotatable drum 3 due to its deadweight. That is, rotatable drum
3 is rotationally operated at a rotational frequency to such an extent that the laundry
does not stick to the inner peripheral wall surface of rotatable drum 3 by centrifugal
force, for example at the order of 50 rpm or lower, though depending also on the amount
of laundry water. At this time, rotatable drum 3 may be rotated in the same one direction
or may be periodically rotated in the reverse direction. Thereby, kinetic energy at
the time of dropping is applied to the laundry, to allow effective cleaning of the
laundry.
[0097] Then, simultaneously with the first low-speed agitating step, controller 22 turns
on circulation pump 17 to drive it for example for the order of one minute, and circulates
the washing and/or rinsing water with the detergent sufficiently dissolved therein
from outlet 30 into rotatable drum 3 through circulation channel 16 (Step S7). This
proceeds impregnation of the washing and/or rinsing water into the laundry. It is
to be noted that circulation pump 17 is driven at a rotational frequency at which
the washing and/or rinsing water sufficiently is spewed out into rotatable drum 3
and easily impregnated into the laundry.
[0098] Next, controller 22 turns off and halts circulation pump 17 (Step S8). Thereby, the
washing and/or rinsing water is brought into the state of not being circulated through
circulation channel 16 for example for the order of one minute, and retained in rotatable
drum 3 and vessel 2 in order to remove foam having generated during the circulation.
[0099] Next, controller 22 again activates circulation pump 17 for example after the lapse
of the order of one minute from the halting of circulation pump 17 (Step S9). Accordingly,
the washing and/or rinsing water is again circulated as spewed out from outlet 30
into rotatable drum 3 through circulation channel 16.
[0100] Then at the re-activation of circulation pump 17, controller 22 reads an output voltage
from the transparency sensor to detect a transparency of the washing and/or rinsing
water. At this time, controller 22 determines an amount of foam of the washing and/or
rinsing water from the output voltage as the read transparency (Step S10).
[0101] Here, the detection operation of the transparency sensor for determining the amount
of foam of the washing and/or rinsing water will be described below with reference
to FIG. 8.
[0102] FIG. 8 is a diagram showing an example of the output voltage of the transparency
sensor in the washing step of the rotatable drum type washing machine according to
the third exemplary embodiment of the present invention. It is to be noted that FIG.
8 is one obtained by monitoring the output voltage of the transparency sensor from
the start of cleaning, for example.
[0103] As shown in FIG. 8, when circulation pump 17 is turned on (Step S7) simultaneously
with the first low-speed agitating step (Step S6) after completion of supply of the
water, the washing and/or rinsing water with the detergent dissolved therein is spewed
out from outlet 30 into rotatable drum 3 in the shower form through circulation channel
16. This leads to generation of foam by the detergent. At this time, due to generation
of the foam, the output voltage of the transparency sensor abruptly increases (Z1),
and when a certain period of time (not longer than one minute) elapses, the output
voltage of the transparency sensor is settled at a stable value (Z2).
[0104] Then, when circulation pump 17 is turned off and halted after the lapse of one minute
from the start of driving of circulation pump 17 (Step S8), circulation of the washing
and/or rinsing water through circulation channel 16 stops. In this case, since the
generated foam is retained in rotatable drum 3 or vessel 2 apart from intake 18 of
circulation channel 16 which is located at a lower position than the water surface
of the washing and/or rinsing water in vessel 2, the transparency of the washing and/or
rinsing water in the vicinity of intake 18 increases. For this reason, the output
voltage of the transparency sensor gradually decreases (Z3), and when a certain period
of time (not longer than one minute) elapses, the output voltage of the transparency
sensor is settled at a stable value (Z4).
[0105] At this time, since agitating is kept being performed in rotatable drum 3 for two
minutes when circulation pump 17 is turned on and off, impregnation of the washing
and/or rinsing water into the laundry is promoted, and dirt on the laundry comes up.
It is to be noted that, although foam is generated by agitating of the washing and/or
rinsing water and the laundry by rotation of rotatable drum 3, the more dirt the laundry
has, the less foam tends to be generated because a larger amount of detergent component
is consumed.
[0106] Moreover, as shown in FIG. 8, after the lapse of one minute from the halting of circulation
pump 17, circulation pump 17 is turned back on (Step S9). Thereby, the foam retained
on the water surface of the washing and/or rinsing water in rotatable drum 3 and vessel
2 is sucked from intake 18 into circulation channel 16 together with the washing and/or
rinsing water. At this time, when there is a little dirt on the laundry or the amount
of detergent is excessively large with respect to the dirt, excessive foam is generated
for two minutes from the start of cleaning, and much foam having been generated passes
through circulation channel 16.
[0107] At this time, after a predetermined time T0 (e.g., ten seconds) since driving of
circulation pump 17 has been resumed, the output voltage (Z5) of the transparency
sensor is detected, to determine an amount of foam.
[0108] At this time, as shown in FIGS. 7 and 8, when a value of the output voltage of the
transparency sensor is a predetermined value, e.g. a value smaller than 4.5 V (YES
in Step S10), the amount of foam is determined to be not larger than estimated.
[0109] Next, after determination of the amount of foam, standby is performed until a set
time is reached (NO in Step S11). When the set time elapses (YES in Step S11), controller
22 controls driving of motor 7, to execute a high-speed rotation step for rotating
rotatable drum 3 at a high speed (Step S12). At this time, the rotational frequency
of rotatable drum 3 in the high-speed rotation step is a rotational frequency at which
the laundry sticks to the inner wall surface of rotatable drum 3. Specifically, it
is a rotational frequency that is high enough to allow moisture of the laundry in
rotatable drum 3 to be forcibly removed by centrifugal force, e.g., preferably not
lower than 150 rpm and further preferably not lower than 300 rpm. Moreover, the time
T when rotatable drum 3 is rotated at a high speed is set relatively short, e.g.,
for 30 seconds so long as the washing and/or rinsing water contained in the laundry
can be rinsed for the time T. It is to be noted that the high-speed rotation step
may be performed by a successive one operation, or may be performed by an intermittent
repeated on/off operation for a short period of time. At this time, since excessive
foam may be generated by the detergent by high-speed rotation of rotatable drum 3,
in the case of repeated operation, it is preferable to intermittently perform high-speed
rotation.
[0110] Thereby, at the time of the first low-speed agitating step, the washing and/or rinsing
water in the vicinity of fibers of clothes which contain the detergent made of a surfactant
attached to a dirt substance of the fibers of the clothes is removed by centrifugal
force by high-speed rotation of rotatable drum 3, thus allowing efficient removal
of the dirt substance from the fibers of the clothes together with the washing and/or
rinsing water. Further, during high-speed rotation of rotatable drum 3, the washing
and/or rinsing water is circulated by circulation pump 17 and spewed out in the shower
form toward the laundry in rotatable drum 3, thus allowing effective absorption of
the washing and/or rinsing water not attached with dirt into the laundry. This promotes
replacement of the washing and/or rinsing water included in the fibers of the clothes,
to allow effective cleaning of the laundry.
[0111] Next, when the time T for the high-speed rotation step is not longer than 30 seconds
(NO in Step S12), standby is performed until 30 seconds elapse and the high-speed
rotation of rotatable drum 3 is kept.
[0112] Subsequently, when 30 seconds elapse as the time T for the high-speed rotation step
(YES in Step S12), controller 22 carries out a second low-speed rotation step (Step
S13). Similarly to the first low-speed agitating step in Step S6, in the second low-speed
agitating step, circulation pump 17 is activated and the washing and/or rinsing water
is spewed out from outlet 30 into rotatable drum 3 through circulation channel 16.
At this time, rotatable drum 3 is rotated at a rotational frequency to such an extent
that the laundry does not stick but rolls over in rotatable drum 3, e.g., 30 rpm.
It is to be noted that circulation pump 17 may be continuously operated or intermittently
operated, to discharge the washing and/or rinsing water from outlet 30 into rotatable
drum 3.
[0113] That is, the second low-speed agitating step is further performed after the high-speed
rotation step, thus allowing further peeling of the remaining dirt substance on the
fibers of the clothes again by the chemical function of the detergent and the mechanical
function associated with rotation of rotatable drum 3. At this time, when a concentration
of the dirt substance in the washing and/or rinsing water among the fibers of the
clothes is high, the dirt might be attached to the fibers of the clothes again. However,
the dirt attached to the surfactant of the detergent and surrounded generally tends
not to be attached again, and only a surfactant not attached to dirt is attached to
the laundry. Hence it is possible to peel the dirt substance only with respect to
the remaining dirt by the chemical function by the detergent.
[0114] Next, it is determined whether or not the second low-speed agitating step has been
executed for a predetermined time (Step S14). When the second low-speed agitating
step has not been executed for the predetermined time (NO in Step S14), standby is
performed until the predetermined time has elapsed. At this time, the time for executing
the second low-speed agitating step may be long enough when the remaining detergent
is sufficiently impregnated into the laundry, and hence a predetermined time not depending
on an amount of cloths is set, e.g., 5.5 minutes in the present exemplary embodiment.
[0115] Then, after execution of the second low-speed agitating step for the predetermined
time (YES in Step S14), the washing step is completed. This can reduce a step using
calculation processing or a constant table for controlling the washing step, so as
to alleviate a load required for the step of controller 22.
[0116] On the other hand, when the output voltage of the transparency sensor is larger than
a predetermined value (e.g., output value is not smaller than 4.5 V) (NO in Step S10),
controller 22 determines that the amount of foam generated in rotatable drum 3 is
excessive. In that case, the step does not move to the high-speed rotation step of
Step S12 but the first low-speed agitating step of Step S6 is continued, and after
the lapse of a predetermined time (e.g., 5.5 minutes) (Step S14), the washing step
is completed.
[0117] It is to be noted that, although not described in FIG. 7, when the output voltage
of the transparency sensor is far larger than the predetermined value in Step S10
(e.g., not smaller than 4.8 V), the washing step may be suspended, and the defoaming
step may be provided in which part of the washing and/or rinsing water in vessel 2
is discharged to discharge foam and the washing and/or rinsing water is again supplied
as much as necessary, to erase foam. Hence an influence on the cleaning performance
exerted by generation of excessive foam can be made small.
[0118] As described above, according to the present exemplary embodiment, when the output
voltage of the transparency sensor becomes not smaller than a predetermined value
in a predetermined time during the washing step, the generated foam is judged to be
much since dirt on the laundry is far below the detergency of the detergent. Then,
the cleaning is completed without performing the high-speed rotation step. It is thereby
possible to realize a rotatable drum type washing machine capable of suppressing a
wasteful cleaning operation and power consumption.
[0119] It is to be noted that in the present exemplary embodiment, the description has been
given using the example where controller 22 reads the output voltage of the transparency
sensor after the predetermined time (10 seconds after re-activation of circulation
pump 17), to determine the amount of foam, but this is not restrictive. For example,
the output voltage of the transparency sensor may be read periodically or constantly
during the time from Step S6 to Step S12 where rotatable drum 3 is rotated at a high
speed, namely during the time set in Step S11. Hence it is possible to determine whether
or not to perform the high-speed rotation step at the time when the output voltage
of the transparency sensor becomes not smaller than the predetermined value. Therefore,
for example in the case of using such a material that is, for a type of a laundry,
foamed after a predetermined time (10 seconds) detected by the transparency sensor,
even if much foam is generated after the predetermined time, cleaning can be completed
without performing a high-speed rotation step for further foaming. This can result
in further suppression of a wasteful cleaning operation and power consumption.
[0120] Moreover, in the present exemplary embodiment, the description has been given using
the example where the output voltage of the transparency sensor is read to determine
the amount of foam, but this is not restrictive. For example, a foam detection water-level
sensor for detecting an amount of foam may be used. It should be noted that in the
foam detection water-level sensor, for example, electrodes may be installed at two
places. One place is on the wall surface of vessel 2 which is located in the vicinity
of intake 18 and submerged into the water without fail at the time of performing the
washing step, and the other place is on the wall surface of vessel 2 which is submerged
into the water when a predetermined amount of washing and/or rinsing water is supplied
and foam is generated in an amount not smaller than estimated. The foam detection
water-level sensor may detect a change in resistance value between those electrodes.
Accordingly, even when the turbidity of the washing and/or rinsing water itself becomes
high due to dissolution of dirt on the laundry thereinto regardless of an amount of
foam, it is possible to detect the amount of foam itself regardless of the transparency
of the washing and/or rinsing water. This can result in determination of the amount
of foam regardless of the kind of dirt. Similarly, the foam detector made of the electrode
sensor configured by a pair of electrodes may be provided and the amount of foam may
be detected, the electrode sensor having been described in the first exemplary embodiment.
[0121] Further, in the present exemplary embodiment, the description has been given using
the example where the control is performed by the controller configured by the microcomputer,
but this is not restrictive. For example, the control may be carried out in the form
of a program cooperated with a hardware resource such as an electric/information appliance,
a computer or a server which is provided with a CPU (or a microcomputer), a RAM, a
ROM, a storage/record device, an I/O or the like. Accordingly, it is possible to easily
install and control distribution, updating and the like of a new function by a program
being recorded in a record medium such as a magnetic medium and optical medium or
being delivered by use of a communication line such an the Internet.
FOURTH EXEMPLARY EMBODIMENT
[0122] A rotatable drum type washing machine in a fourth exemplary embodiment of the present
invention will be described below with reference to FIGS. 9A and 9B. It is to be noted
that, since the rotatable drum type washing machine of the fourth exemplary embodiment
has the same configuration as that of the rotatable drum type washing machine described
in the third exemplary embodiment, a detailed description thereof will be omitted.
[0123] FIGS. 9A and 9B are flowcharts showing cleaning control of the rotatable drum type
washing machine in the fourth exemplary embodiment of the present invention.
[0124] The rotatable drum type washing machine of the present exemplary embodiment is different
from that of the third exemplary embodiment in that, when the output voltage of the
transparency sensor becomes not smaller than a predetermined value, controller 22
performs control by at least either reducing the rotational frequency of rotatable
drum 3 in the high-speed rotation step or reducing the time for the high-speed rotation
step. The other control method is similar to that of the third exemplary embodiment
up to Step S9 shown in FIGS. 9A and 9B.
[0125] Thereat, the control after Step S15, which is different from that in the third exemplary
embodiment, will be principally described.
[0126] As shown in FIGS. 9A and 9B, similarly to the third exemplary embodiment, for example
after the lapse of the order of one minute from the halting of circulation pump 17
after execution of Step S1A for supplying water to Step S8, controller 22 again activates
circulation pump 17 (Step S9).
[0127] Then, controller 22 reads the output voltage from the transparency sensor to detect
the transparency of the washing and/or rinsing water. Controller 22 then determines
an amount of foam of the washing and/or rinsing water from the output voltage as the
read transparency (Step S15).
[0128] At this time, when the output voltage of the transparency sensor is smaller than
4.0 V (YES in Step S15), the amount of foam is judged to be normal. Standby is then
performed until a set time elapses (NO in Step S16), and after the lapse of the set
time (YES in Step S16), the high-speed rotation step is executed (Step S17). The high-speed
rotation step is executed by rotating rotatable drum 3 at 300 rpm for 30 seconds,
for example.
[0129] On the other hand, when the output voltage of the transparency sensor is not smaller
than 4.0 V (NO in Step S15), it is determined whether or not the output voltage of
the transparency sensor is not smaller than 4.5 V (Step S18).
[0130] At this time, when the output voltage of the transparency sensor is smaller than
4.5 V (YES in Step S18), the amount of foam is judged to be excessive. Standby is
then performed until a set time elapses (NO in Step S19), and after the lapse of the
set time (YES in Step S19), the high-speed rotation step is executed (Step S20). In
this case, the rotational frequency of rotatable drum 3 is reduced as compared with
the case where the output value of the transparency sensor is smaller than the predetermined
value (4.0 V) in Step S15, and the high-speed rotation step is executed at 150 rpm
for 30 seconds, for example.
[0131] Further, when the output voltage of the transparency sensor is not smaller than 4.5
V (NO in Step S18), it is determined whether or not the output voltage of the transparency
sensor is not smaller than 4.8 V (Step S21) as shown in FIG. 9B. When the output voltage
of the transparency sensor is smaller than 4.8 V (YES in Step S21), standby is performed
until a set time elapses (NO in Step S22), and after the lapse of the set time (YES
in Step S22), the high-speed rotation step is executed (Step S23). In this case, the
time for rotating rotatable drum 3 is reduced as compared with the case where the
output voltage value of the transparency sensor is smaller than the predetermined
value (4.5 V) in Step S18, and the high-speed rotation step is executed at 150 rpm
for 15 seconds, for example.
[0132] On the other hand, when the output voltage of the transparency sensor is not smaller
than 4.8 V (NO in Step S21), the first low-speed agitating step of Step S6 is continued
without performing the high-speed rotation step, and after the lapse of a predetermined
time (YES in Step S24), the washing step is completed.
[0133] It should be noted that in the present exemplary embodiment, the description has
been given using the example where reduction in rotational frequency in the high-speed
rotation step and reduction in time therefor are simultaneously performed in accordance
with the value of the output voltage of the transparency sensor, but this is not restrictive.
For example, either the reduction of the rotatable drum in rotational frequency in
the high-speed rotation step or the reduction of the rotatable drum in time for the
high-speed rotation step may be executed. That is, when the amount of generated foam
is large since dirt on the laundry is below the detergency of the amount of detergent
inserted, it can be assumed that there is a little dirt to be peeled from the laundry.
Therefore, even one of reduction in rotational frequency of the rotatable drum in
the high-speed rotation step or reduction in for the high-speed rotation step is executed,
sufficient cleaning performance can be obtained. This can result in realization of
a rotatable drum type washing machine which can further suppress a wasteful cleaning
operation and power consumption.
[0134] It is to be noted that, although the description has been given using the rotatable
drum type washing machine as the example in each of the above exemplary embodiments,
this is not restrictive, and for example, a rotatable drum type washing/drying machine
may be applied, and a similar effect can be obtained.
[0135] Further, in each of the above exemplary embodiments 3 and 4, the descriptions have
been given by use of the example of performing the low-speed agitating step twice,
but this is not restrictive. For example, the low-speed agitating step may be performed
just once. This leads to reduction in washing time.
[0136] The rotatable drum type washing machine of the present invention includes: a rotatable
drum for housing laundry; a vessel for housing the rotatable drum; a motor for driving
the rotatable drum; a water supply unit for supplying washing and/or rinsing water
into the vessel; a circulator for circulating the washing and/or rinsing water in
the vessel into the rotatable drum; a foam detector for detecting an amount of foam;
and a controller for controlling at least one of the following steps a washing step,
a rinsing step and water removal step. The controller is configured to control so
as to rotate the rotatable drum at a predetermined rotational frequency and configured
to control a spraying of the washing and/or rinsing water by the circulator onto the
laundry in the rotatable drum based on the amount of foam detected by the foam detector.
[0137] Thereby, based on the amount of foam detected by the foam detector, the rotatable
drum is rotated at the predetermined rotational frequency, to enhance the cleaning
effect of laundry. For example, when there is much dirt on laundry, the foam detector
judges that the amount of foam is small, and the rotatable drum is rotated at a predetermined
rotational frequency at which the laundry sticks to the inner surface of the rotatable
drum. As a result, the washing and/or rinsing water impregnated among the fibers of
the laundry is discharged by centrifugal force together with dirt. Further, the washing
and/or rinsing water is sprayed by the circulator onto the laundry in the rotatable
drum, thereby loading (infiltrating) the washing and/or rinsing water into the fibers
of the laundry. As a result, when there is much dirt on the laundry, replacement of
the washing and/or rinsing water among the fibers of the laundry is promoted to accelerate
a dirt removing effect so as to enhance a cleaning effect. Further, by detecting the
amount of foam after the lapse of a predetermined time from the start of the washing
step, it is possible to promote dissolution of the detergent by rotation of the rotatable
drum, while accurately detecting the amount of foam.
[0138] Moreover in the rotatable drum type washing machine of the present invention, when
the amount of foam detected by the foam detector is small, the controller rotates
the rotatable drum at a predetermined rotational frequency at which the laundry sticks
to the inner surface of the rotatable drum. Thereby, the washing and/or rinsing water
in the vessel is rolled up and agitated by high-speed rotation of the rotatable drum.
As a result, dissolution of the detergent and generation of foam are promoted, while
the amount of foam can be more accurately detected.
[0139] Moreover in the rotatable drum type washing machine of the present invention, the
controller rotates the rotatable drum at a rotational frequency at which the laundry
sticks to the inner surface of the rotatable drum at a start of the washing step,
and thereafter, the controller supplies the washing and/or rinsing water and the controller
is configured to control to detect the amount of foam by the foam detector. Hence
it is possible to rotate the rotatable drum from the start of the washing step, so
as to supply water in a state where non-uniformity of the laundry is prevented. By
driving the rotatable drum to be rotated at a high speed in the state where the laundry
is not one-sided and is stable in rotatable drum 3, it is possible to sufficiently
roll up and agitate the washing and/or rinsing water in the vessel, so as to promote
dissolution of the detergent and generation of the foam. As a result, the amount of
foam can be more accurately detected by the foam detector.
[0140] Moreover in the rotatable drum type washing machine of the present invention, the
controller is configured to control to detect the amount of foam by the foam detector
after the lapse of a predetermined time from the start of the washing step. Therefore,
the rotatable drum is rotated until the predetermined time has elapsed, and hence
it is possible to promote dissolution of the detergent into the washing and/or rinsing
water, while promoting generation of foam. This can result in accurate detection of
the amount of foam in accordance with dirt on the laundry, so as to control rotation
of the rotatable drum.
[0141] Further in the rotatable drum type washing machine of the present invention, the
washing step has: a low-speed agitating step of rotating the rotatable drum at such
a speed at which the laundry is not attached to at least the inner surface of the
rotatable drum, and a high-speed rotation step of rotating the rotatable drum at a
speed at which the laundry does not stick to the inner surface of the rotatable drum,
and the controller switches to the high-speed rotation step when the amount of foam
detected by the foam detector comes into a predetermined condition during the low-speed
agitating step.
[0142] According to this configuration, first, the rotatable drum is rotated at a low speed
to bring the laundry into the state of being wet with washing and/or rinsing water
sufficiently mixed with the detergent, and hence it is possible to efficiently attach
the surfactant of the detergent to the dirt on the laundry. Subsequently, by rotating
the rotatable drum at a high speed in accordance with the output of the foam detector,
it is possible to peel from the laundry the dirt attached to the detergent and the
washing and/or rinsing water mixed with the detergent in the vicinity of the fibers
of the laundry. It is thereby possible to prevent unnecessary foaming of the detergent,
to perform the cleaning operation as much as necessary. This can result in suppression
of a wasteful operation and power consumption.
[0143] Further in the rotatable drum type washing machine of the present invention, when
the amount of foam detected by the foam detector becomes not smaller than a predetermined
value, the controller is configured not to perform the high-speed rotation step. Accordingly,
when the dirt on the laundry is below the detergency of the amount of detergent inserted
and the amount of foam generated is large, the cleaning operation is completed without
rotating the rotatable drum at a high speed. This can reduce a load on the motor in
the case of rotating the rotatable drum at a high speed in the state of excessive
foam being generated, thereby allowing elimination of a wasteful operation and power
consumption.
[0144] Further in the rotatable drum type washing machine of the present invention, when
the amount of foam detected by the foam detector becomes not smaller than a predetermined
value, the controller is configured to perform at least one of reduction in rotational
frequency of the rotatable drum in the high-speed rotation step or reduction in duration
of time for the high-speed rotation step.
[0145] According to this configuration, when the dirt on the laundry is below the detergency
of the amount of detergent inserted and the amount of foam generated is excessive,
there is a little dirt to be peeled from the laundry, and hence it is possible to
perform at least either reduction in rotational frequency of the rotatable drum in
the high-speed rotation step or reduction in time for the step. Therefore, it is possible
to obtain sufficient cleaning performance and also suppress generation of excessive
foaming. This can reduce a load on the motor in the case of rotating the rotatable
drum at a high speed in the state of excessive foam being generated, thereby allowing
elimination of a wasteful operation and power consumption.
[0146] Moreover, in the rotatable drum type washing machine of the present invention, the
foam detector comprises the transparency sensor for detecting transparency of the
washing and/or rinsing water for determining the amount of foam based on an output
value of the transparency sensor. Hence it is possible to easily determine whether
the amount of foam is large or small just by monitoring the transparency of the washing
and/or rinsing water.
INDUSTRIAL APPLICABILITY
[0147] According to the present invention, it is possible to promote replacement of washing
and/or rinsing water among fibers of laundry for accelerating removal of dirt, so
as to enhance the cleaning effect, and hence the present invention is useful for such
a technical field as a rotatable drum type washing machine.
REFERENCE MARKS IN THE DRAWINGS
[0148]
- 1
- enclosure
- 2
- vessel, for example water tub
- 3
- rotatable drum
- 3A
- rotational shaft
- 4
- baffle
- 5
- small hole
- 6
- opening
- 7
- motor
- 8
- belt
- 9
- pulley
- 10
- water supply valve (water supply unit)
- 11
- water supply channel
- 12
- detergent case
- 13
- water tank unit
- 14
- heater
- 15
- temperature detector
- 16
- circulation channel
- 17
- circulation pump (circulator)
- 18
- intake
- 19,30
- outlet
- 20
- switch valve
- 21
- drainage channel
- 22
- controller
- 23
- door
- 24
- operator
- 25
- weight detector
- 26
- water-level detector
- 27,28,32
- foam detector
- 29
- water supply inlet
- 31
- filter
- 33
- laundry