TW202020259A - washing machine - Google Patents

Abstract

A washing machine according to the present disclosure is provided with: a housing; an outer tank that is elastically supported inside the housing; an inner tank that is included in the outer tank and is rotatably disposed therein; a water supply part that supplies water into the outer tank; a water level detection part that detects the water level in the outer tank; a draining part that drains water in the outer tank; a foam detection part provided with a pair of electrodes comprising a first electrode and a second electrode; and a control unit that controls a washing operation comprising at least one of washing, rinsing, and dehydration. If resistance between the pair of electrodes has become less than a predetermined value by the time when the water level reaches a predetermined water level, the control unit determines that short circuit has occurred between the pair of electrodes.

Description

washing machine

Field of invention The present disclosure relates to a washing machine for stirring clothes and washing water.

Background of the invention Japanese Patent Laid-Open No. 2007-117139 discloses a washing machine that suppresses the generation of detergent foam that occurs during washing.

The drum-type washing machine in Japanese Patent Laid-Open No. 2007-117139 is provided with: an outer tank; a rotating drum, which is rotatably arranged in the outer tank; a drain section, which drains the washing water in the outer tank; and a foam detection section, Consists of a pair of electrodes. After the foam detection part detects the foam, the control part shifts to the weak washing program and does not operate the drainage part within a predetermined time. After a predetermined time elapses, if the foam detection unit does not detect foam, it will return to the normal washing process. If the foam detection unit detects foam, it will cause the drainage unit to move and drain the water in the outer tank. drain.

Summary of the invention However, the above-mentioned conventional washing machine has a problem that the generation of detergent foam cannot be determined when a short circuit occurs in the foam detection unit.

The present disclosure provides a washing machine provided with a foam detection part for detecting the generation of detergent foam that occurs during washing, and can appropriately handle a short circuit of the foam detection part.

The washing machine in the present disclosure includes: a casing; an outer tank, which is elastically supported inside the casing; an inner tank, which is enclosed in the outer tank, and is arranged to rotate freely; a water supply part, which supplies water to the outer tank; The water level detection section detects the water level in the outer tank; the drainage section drains the water in the outer tank; the foam detection section includes a pair of electrodes composed of a first electrode and a second electrode; and a control section , Control the washing operation composed of at least one of washing, flushing, and dehydration. During the period until the water level reaches a predetermined water level, when the resistance between the pair of electrodes is lower than a predetermined value, the control unit determines that the pair of electrodes is short-circuited.

The washing machine in the present disclosure is provided with a foam detection section for detecting the generation of detergent foam that occurs during washing, and can appropriately handle the short circuit of the foam detection section.

Forms for carrying out the invention Hereinafter, the embodiments will be described in detail while referring to appropriate drawings. (Embodiment 1)

FIG. 1 is a side sectional view of a drum-type washing machine in Embodiment 1 of the present disclosure.

As shown in FIG. 1, the water tank 33 is anti-vibration-supported so as to be swingable by an anti-vibration member 41 or the like disposed below the washing machine body 39. The rotary drum 31 is rotatably installed in the water tank 33, and the rotation center is inclined downward from the front side toward the back side. The rotary drum 31 is formed in a bottomed cylindrical shape, and a plurality of water passage holes 32 are provided on the entire surface of the outer peripheral portion. On the inner wall surface of the rotary drum 31, a plurality of protrusion plates 36 for clothes stirring are provided. An opening 38 is provided on the front side of the water tank 33 and the rotating drum 31, and the opening 38 is covered by the lid 37 to be opened and closed freely. By opening the cover 37, the user can take out the laundry through the opening 38 and put it into the rotary drum 31.

The water supply valve (water supply part) 44 supplies water into the water tank 33 through the water supply path 45. The control unit 57 is arranged below the main body. One end of the drain path 42 is connected to the lower portion of the water tank 33, and a drain valve (drain portion) 43 is connected to the other end of the drain path 42 to drain the washing water in the water tank 33.

A rotating shaft 34 is provided on the back of the rotating drum 31. The rotating shaft 34 is connected to the motor 35 installed on the back of the water tank 33. The motor 35 is constituted by a brushless dc motor or the like, and is controlled by the control unit 57 and drive circuit (not shown), etc., to be able to rotate in forward and reverse directions and to change the number of rotations. The signal from the current detection circuit (not shown) detects the load applied to the motor 35, that is, the amount of laundry.

The drum-type washing machine is configured to achieve a drying function, and includes a heater 47, a blower fan 48, and a warm air blower path 49. In addition, a hot air inlet (not shown) for taking in the air in the water tank 33 is provided on the back of the upper surface of the water tank 33. The warm air blowing port 51 is provided above the back of the water tank 33. The warm air flows into the water tank 33 and the rotary drum 31 in the direction of arrow a, and the air inside the rotary drum 31 and the water tank 33 circulates after being heated, and the laundry is dried.

The control unit 57 is input with information from the input setting unit 58 for setting the operation stroke and the like. The control unit 57 will cause the display unit 59 to display the set content to notify the user based on the input information. After the operation is set by the input setting unit 58, the data from the water level detection unit 46 that detects the water level in the water tank 33 is input to the control unit 57, and the control unit 57 passes through the load drive unit (not shown) Shown) to control the operation of the drain valve 43, the water supply unit 44, the blower fan 48, the heater 47, and the like. In addition, the control unit 57 controls the motor 35 through a drive circuit (not shown). The control unit 57 performs an operation of a washing step composed of at least one of washing, flushing, dewatering, and drying.

The foam detection unit 70 is composed of the electrode 70a disposed below the water tank 33 and disposed above the water tank 33, or is disposed in the warm air supply path 49 from the warm air supply port 51 A pair of upper electrodes 70b in a predetermined area is formed. Here, the predetermined area means an area where the detergent foam generated in the water tank 33 can reach the upper electrode 70b. This is because the generation of lotion foam can be detected by the lotion foam reaching the upper electrode 70b. In addition, the upper electrode 70b is disposed at a higher position than the lower electrode 70a.

Next, the position where the lower electrode 70a and the upper electrode 70b are arranged will be further described using FIG. 1. The water levels h1, h2, and h3 are the water levels of the washing water in the water tank 33 when the lower end of the water tank 33 is used as a reference. The water level h1 is the water level when the normal cleaning procedure described later is executed. The water level h2 is the water level corresponding to the height position of the lower end of the rotary drum 31. The water level h3 is the water level corresponding to the height position of the lower electrode 70a. As shown in FIG. 1, the height of the water level is such that h1>h2>h3. As an example, the water level h1 is higher than the water level h2 by about 100 mm.

The lower electrode 70a is arranged at a height position corresponding to a water level h3 lower than the water level h2. That is, the lower electrode 70a is disposed below the water tank 33 at a position lower than the rotating drum 31. In this way, it is possible to distinguish between the short circuit and the abnormal foaming of the foam detection part 70 for identification. The upper electrode 70b is arranged at a position higher than the water level h1.

In addition, in FIG. 1, although the lower electrode 70 a and the upper electrode 70 b are disposed behind the water tank 33, it is not limited to this, and the lower electrode 70 a and the upper electrode 70 b may also be disposed in the water tank 33 Before.

The foam detection unit 70 is connected to a resistance value determination circuit (not shown). By comparison with the reference resistance in the resistance value determination circuit, the resistance between the lower electrode 70a and the upper electrode 70b is detected. As long as the resistance value between the lower electrode 70a and the upper electrode 70b is equal to or greater than the threshold value, the control unit 57 determines that no foam has entered between the pair of electrodes. If the foam penetrates between the pair of electrodes, a current path caused by the foam is formed between the electrode 70a under the water immersion and the upper electrode 70b, and a resistance value lower than the threshold value is detected. The resistance value for determination of the resistance value determination circuit is set to be less than the threshold value (for example, 500 kΩ) when foam is present, and set to be greater than the threshold value (for example, 500 kΩ) when foam is not present.

For the drum-type washing machine constructed as above, FIGS. 2 to 4 will be used to describe the action and effect when the foam detection unit detects foam during washing.

FIG. 2 is an operation flowchart of the control unit of the drum-type washing machine in Embodiment 1 of the present invention. FIG. 3(a) is a schematic diagram when abnormal foaming occurs in the foam detection unit of the drum-type washing machine. FIG. 3( b) is a schematic diagram of a short circuit caused by accumulations in the foam detection part of the same drum washing machine, and FIG. 4 is a graph showing the time change of the resistance value of the foam detection part of the same drum washing machine and the water level in the sink Schematic.

After the cleaning step is started, the foam detection part 70 will start the detection of the resistance value. During the period until the water level in the water tank 33 reaches the water level h2 (S101) corresponding to the height of the lower end of the rotary drum 31, the resistance value detected by the foam detection unit 70 is not lower than the threshold value (for example, 500 kΩ) At the time (S102, No), the control unit 57 determines that a short circuit has not occurred between the pair of electrodes and performs the normal cleaning procedure (S103). Here, the normal cleaning procedure (S103) refers to, for example, supplying water to the water level h1, and then rotating the rotary drum 31 for 12 seconds and then stopping for a stirring time of 1 second, and operating at a rotation number of 45 r/min. Here, the so-called normal cleaning program is also called the first cleaning program.

As indicated by the dashed line B in FIG. 4, in the normal cleaning procedure (S103), after reaching the water level h2, it will be determined whether the resistance value of the foam detection section 70 is less than the threshold value (S104). If the resistance value is less than the threshold value, the control section 57 will determine that abnormal foaming has occurred (S105). The abnormal foaming occurs because the washing water containing the detergent component is stirred by the rotation of the rotary drum 31, and as shown in FIG. 3(a), electricity is applied between the pair of electrodes. When it is determined that abnormal foaming has occurred, the control unit 57 performs a defoaming procedure such as draining the water in the water tank 33 by the drain unit 43 (S106).

Then, after ending the first predetermined time, for example, a normal cleaning procedure of 15 minutes (S107), the control unit 57 ends the cleaning step (S108) and moves to the next step.

On the other hand, as shown by the solid line A in FIG. 4, if the resistance value of the foam detection section 70 is less than the threshold value (S102, Yes) before the water level reaches h2, the control section 57 can determine that abnormal foaming occurs. does not happen. This is because, until the water level in the water tank 33 reaches h2, the washing water containing the detergent component is not stirred by the rotation of the rotary drum 31, so that abnormal foaming does not occur. Therefore, when the resistance value is less than the threshold value, it can be determined that a short circuit between electrodes has occurred, so if the resistance value is less than the threshold value before the water level reaches h2 (S102, Yes), the control unit 57 will determine that a short circuit has occurred (S109 ).

The short circuit between the electrodes is caused by the accumulation of materials between the electrodes. The so-called deposits refer to residues (detergent residues) of detergent components or threads from the laundry. When these are accumulated between the electrodes of the foam detection part 70, as shown in FIG. 3(b), the washing water will form a thin film using the residue of the detergent component or the thread as a medium by surface tension, so that the electrode Short circuit.

After S109, no matter what value the resistance value detected by the foam detection unit 70 becomes, the water in the water tank 33 will not be drained by the drainage unit 43 until the cleaning is completed (S108) and the transition to the next step The action of draining. This is because, as described above, an object other than foam adheres between the pair of electrodes, so that the control unit 57 cannot accurately determine whether there is abnormal foaming in the water tank 33 based on the resistance value between the pair of electrodes. When it is determined that there is a short circuit (S109), the foam detection unit 70 does not function normally. Therefore, if the drainage operation is performed based on the determination of the foam detection unit 70, there is a possibility that the foam is not abnormally foamed but is erroneously detected as abnormal foaming. Once an erroneous detection occurs, not only will it cause useless drainage, the detergent components contained in the washing water in the water tank 33 will also be drained together, so the cleaning performance will be significantly reduced.

However, after S109, until the end of the cleaning step (S108), abnormal foaming may occur. Therefore, when the short circuit determination (S109) is performed, the control unit 57 executes the first step to suppress the abnormal foaming. Weak cleaning program (S110). The first weak cleaning procedure refers to, for example, the rotating drum 31 is rotated for 10 seconds and then stopped for a weak stirring time of 5 seconds, and is operated at a rotation number of 35 r/min. The first weak cleaning program has weaker agitation than the normal cleaning program (S103), so that blistering can be suppressed. In addition, the "stirring is weaker than the normal cleaning procedure" means that at least one of the number of rotations and the rotation time of the rotary drum 31 is smaller than the normal cleaning procedure. Here, the so-called first weak cleaning procedure is also referred to as the second cleaning procedure.

After that, the cleaning step is continued for a second predetermined time (S111), for example, after a 15-minute cleaning procedure, the control unit 57 ends the cleaning step (S108) and moves to the next step.

Then, a series of washing operations such as flushing, spin-drying, and drying are sequentially performed, and when the operation is completed, the control unit 57 causes the display unit 59 to display that a short-circuit determination has been made to notify the user. As a result, the user will recognize that the foam detection unit 70 is not functioning normally, and can operate the stroke of the washing water tank 33 or the rotating drum 31 itself (for example, the tank washing stroke). As a result, the detergent residue and the like accumulated between the pair of electrodes of the foam detection unit 70 are removed, and it is possible to prevent the washing machine from continuing to be used in a state where the pair of electrodes is short-circuited.

As described above, the drum-type washing machine in the present disclosure includes: a washing machine body 39; a water tank 33, which is elastically supported inside the washing machine body 39; a rotating drum 31, enclosed in the water tank 33, and configured to rotate freely; a water supply valve 44, Water supply to the water tank 33; the water level detection part 46, which detects the water level in the water tank 33; the drain valve 43, which drains the water in the water tank 33; the foam detection part 70, which consists of a pair of electrodes, namely the lower electrode 70a And the upper electrode 70b; and the control unit 57 controls the washing operation composed of at least one of washing, flushing, and dehydration. During the period until the water level of the water supplied to the water tank 33 by the water supply unit 44 reaches a predetermined water level, the control unit 57 determines that the electrode 70a, 70b is short-circuited when the resistance between the electrodes 70a and 70b is lower than a predetermined value.

By this, even if a short circuit occurs between the lower electrode 70a and the upper electrode 70b, the increase in foam due to abnormal foaming can be suppressed, and unnecessary drainage can be prevented. Therefore, the drum-type washing machine in this embodiment can appropriately handle the short circuit of the foam detection unit 70.

The predetermined water level may also correspond to the height at which the lower end of the rotary drum 31 is located.

The lower electrode 70a may be arranged at a position lower than a predetermined water level.

The lower electrode 70a is provided below the water tank 33, and the upper electrode 70b may be provided above the water tank 33.

The drum type washing machine may further include: a warm air blowing path 49 to circulate warm air for drying the laundry; and a warm air blowing port 51 formed above the back of the water tank 33 and introducing the warm air into the water tank 33. The lower electrode 70a is provided below the water tank 33, and the upper electrode 70b may be provided in a predetermined area from the warm air supply port 51 within the warm air supply path 49.

Alternatively, during the period until the water level supplied to the water tank 33 by the water supply unit 44 reaches the predetermined water level, the resistance between the electrodes 70a and 70b is not lower than the predetermined value, and after reaching the predetermined water level, the resistance between the electrodes When the resistance is lower than the predetermined value, the control unit 57 performs the drainage operation through the drainage valve 43.

Thereby, the control unit 57 determines that abnormal foaming has occurred, and can perform the cleaning procedure after temporarily draining the abnormally foamed washing water. Therefore, the drum-type washing machine in the present embodiment can distinguish between the short circuit and abnormal foaming of the foam detecting portion 70 and can appropriately handle abnormal foaming.

During the period until the water level in the water tank 33 supplied by the water supply unit 44 reaches the predetermined water level, the control unit 57 executes the first cleaning procedure when the resistance between the electrodes is not lower than the predetermined value. Alternatively, during the period until the water level supplied to the water tank 33 by the water supply unit 44 reaches the predetermined water level, the control unit 57 does not perform drainage by the drain valve 43 when it is determined that the electrode 70a and 70b are short-circuited. In the operation, at least one of the rotation number and rotation time of the rotary drum 31 is set to be smaller than the first cleaning procedure, and the second cleaning procedure is executed.

With this, it is possible to suppress the blistering caused by the stirring of the rotary drum 31 more than the normal cleaning procedure. Therefore, the drum-type washing machine in this embodiment can properly handle abnormal foaming even when the foam detection unit is short-circuited.

It may also be provided with: a display unit 59 for notifying the status of the washing operation, and when a short circuit between the electrodes 70a and 70b is determined, the control unit 57 will perform an abnormality with the display unit 59 after the washing step is completed Notice.

With this, the user can recognize that the foam detection part 70 does not function normally. Therefore, by performing the stroke of the washing water tank 33 or the rotating drum 31 itself to remove the deposits accumulated between the electrodes of the foam detection part 70, the short circuit of the foam detection part can be properly handled. (Other embodiments)

As described above, Embodiment 1 has been described as an example of the technology disclosed in the present application, but the technology in the present disclosure is not limited thereto.

Therefore, other embodiments are illustrated below.

In the first embodiment, the drum-type washing machine is described as an example of the washing machine. The washing machine is not limited to a drum-type washing machine as long as it can wash the cloth with water. Therefore, it can also be a vertical washing machine, and also a two-tank washing machine. In addition, in the first embodiment, the drum-type washing machine having a drying function has been described, but the drum-type washing machine having no drying function can also exhibit the same effect. In addition, even in the case where the electrodes are short-circuited due to changes over time, it is still possible to prevent the foam from increasing, and at the same time prevent the cleaning performance from being significantly reduced. Therefore, it is also useful for washing machines and the like that require a preventive part that can protect electrical parts from foam or the like.

In the first embodiment, as an example of the inner groove, the description is made using the rotary drum 31 in which the axis direction is inclined downward from the front side toward the back side. Since the inner tank only needs to be wrapped in the outer tank and arranged to rotate freely, it can also be arranged in the horizontal direction.

In the first embodiment, the short-circuit determination is performed by the change in the resistance value during the period until the water level reaches h2 (S102). However, when the water level in the water tank 33 has reached h2 or more during the period until the operation starts, the aforementioned short-circuit determination (S102) may not be executed. This is because it is impossible to pass through S101 and 102 in order, which leads to a lack of accuracy in the short-circuit determination itself. In this case, since there is a possibility of abnormal foaming, when the resistance value of the foam detecting section 70 is less than the threshold value, it is possible to quickly enter the drainage (defoaming procedure) (S106).

In the first embodiment, after it is determined that abnormal foaming occurs in S105, the abnormal foaming is handled by draining the water in the water tank 33. The treatment of abnormal foaming is not limited to draining the water in the water tank 33, but may also be handled by a cleaning procedure. For example, in the first weak cleaning procedure, as long as the resistance value detected by the foam detection unit 70 is above the threshold after a predetermined time (for example, 1 minute), the control unit 57 determines that there is no foam between the electrodes, that is, it has disappeared. Soaked. In addition, it may also be returned to the normal cleaning procedure (S103), and if the resistance value detected by the foam detection unit 70 is still less than the threshold value, the water in the water tank 33 is drained by the drain unit 43.

In the first embodiment, the first weak cleaning program is performed in S110. In S110, a second weak cleaning program that is weaker than the first weak cleaning program may be entered. Here, the second weak cleaning procedure means that the rotating drum 31 is rotated for 5 seconds and then stopped for a weaker stirring time of 10 seconds, and is operated at a rotation number of 30 r/min. The second weak cleaning program has weaker agitation than the first weak cleaning program, so it is possible to suppress foaming more. When the second weak cleaning program is entered, in order to ensure the cleaning power, the second predetermined time (S111) may be longer than the first predetermined time (S107) (for example, 20 minutes). In addition, it may be configured that the first weak cleaning program is performed in S103 and the second weak cleaning program is performed in S110. Here, the second weak cleaning procedure is also referred to as a third cleaning procedure.

Furthermore, in the first embodiment, the judgment value of the abnormal foaming judgment (S105) in the normal cleaning procedure (S103) and the judgment value of the short circuit judgment (S109) are set to the same threshold (for example, 500 kΩ), but Not limited to this. The abnormal foaming determination value may be the first threshold (for example, 500 kΩ), and the short circuit determination value may be the second threshold (for example, 250 kΩ). Compared with the reduction of the normal resistance value caused by the foaming of the lotion, using a lower resistance value as a reference for short-circuit determination can improve the accuracy of short-circuit determination.

In the first embodiment, the water level h2 is a water level corresponding to the height position of the lower end of the rotary drum 31, but it is not limited to this. The water level h2 only needs to be lower than the water level h1, and the rotation level of the rotary drum 31 is used to stir the washing water containing the detergent component without foaming.

Furthermore, in the first embodiment, the circulation pump 80 communicating with the drainage path 42 is provided, and the circulation path 81 communicating with the circulation pump 80 is communicated with the circulation port 82 at the lower front portion of the water tank 33 to make the washing step The wash water circulates as indicated by arrow b. Although the driving of the circulation pump 80 is not described in the first embodiment, it can be made as follows. It can also be made: during the normal cleaning procedure (S103), the rotation number or operating rate of the circulation pump 80 is increased (for example, 3500r/min, 30 seconds on-30 seconds off), and in the short circuit determination (S109), in order to suppress the Bubble to reduce the rotation speed or operation rate of the circulation pump 80 (for example, 2500r/min, 20 seconds on-40 seconds off), or stop it. With this, it is possible to suppress abnormal foaming due to the driving of the circulation pump 80.

In addition, since the above-mentioned embodiment is an embodiment for exemplifying the technology in the present disclosure, various changes, substitutions, additions, omissions, etc. can be made within the scope of patent application or its equivalent.

The present disclosure can be applied to a washing machine for washing clothes. Specifically, the present disclosure can be applied to vertical washing machines, drum washing machines, two-tank washing machines, and the like.

31: Rotating drum 32: water hole 33: sink 34: axis of rotation 35: Motor 36: Protruding plate 37: Cover 38: opening 39: Washing machine body 41: Anti-vibration member 42: Drainage path 43: Drain valve (drainage section) 44: Water supply valve (water supply department) 45: Water supply path 46: Water level detection department 47: Heater 48: fan 49: Warm air supply path 51: Warm air supply port 57: Control Department 58: Input setting section 59: Display 70: foam detection department 70a, 70b: electrode 80: circulating pump 81: circulation path 82: circulation port a, b: arrow A: solid line B: dotted line h1, h2, h3: water level

FIG. 1 is a side sectional view of a drum-type washing machine in Embodiment 1. FIG. Fig. 2 is an operation flowchart of the control unit of the drum-type washing machine. FIG. 3 is a schematic diagram when abnormal foaming occurs in the foam detection section of the same drum-type washing machine or when a short circuit caused by accumulations occurs. 4 is a schematic diagram showing the time variation of the resistance value of the foam detection part of the same drum type washing machine and the water level in the water tank.

Claims (8)

A washing machine with: case; The outer groove is elastically supported inside the aforementioned housing; Inner slot, enclosed in the aforementioned outer slot, and configured to rotate freely; The water supply department supplies water to the aforementioned outer tank; The water level detection unit detects the water level in the outer tank; The drainage part drains the water in the outer tank; The foam detection unit includes a pair of electrodes composed of a first electrode and a second electrode; and The control unit controls the washing operation composed of at least one of washing, flushing, and dehydration, In addition, during the period until the water level reaches a predetermined water level, when the resistance between the pair of electrodes is lower than a predetermined value, the control unit determines that the pair of electrodes is short-circuited. As in the washing machine of claim 1, wherein the predetermined water level corresponds to the height of the lower end of the inner tank. The washing machine according to claim 1 or 2, wherein the first electrode is arranged at a position lower than the predetermined water level. The washing machine according to any one of claims 1 to 3, wherein the first electrode is provided below the outer tank, and the second electrode is provided above the outer tank. If the washing machine according to any one of claims 1 to 3, it further has: The warm air supply path will circulate the warm air used to dry the laundry; and A warm air supply port is formed above the back of the outer tank, and the warm air is introduced into the outer tank, In addition, the first electrode is provided below the outer groove, The second electrode is provided in a predetermined area from the warm air blowing port in the warm air blowing path. According to the washing machine of any one of claims 1 to 5, during the period until the water level in the outer tank reaches the predetermined water level, the resistance between the pair of electrodes is not lower than the predetermined value, and After the predetermined water level, when the resistance between the pair of electrodes is lower than the predetermined value, the control unit performs a drainage operation through the drainage unit. According to the washing machine of any one of claims 1 to 6, during the period until the water level in the outer tank reaches the predetermined water level, when the resistance between the pair of electrodes is not lower than the predetermined value, the control section Will perform the first cleaning procedure, Moreover, during the period until the water level in the outer tank reaches the predetermined water level, when it is determined that the pair of electrodes is short-circuited, the control unit does not perform the drain operation by the drain unit, but executes the inner tank At least one of the number of rotations and the rotation time is set to a second cleaning program that is smaller than the first cleaning program. If the washing machine according to any one of claims 1 to 7, it has: The display unit is used to notify the status of the washing operation, In addition, when it is determined that the pair of electrodes is short-circuited, the control unit will notify the abnormality via the display unit after the washing operation is completed.

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