washing machine
The washing machine addresses detergent foam during spin-drying by employing a swingable water tank and controlled defoaming operations, enhancing dehydration efficiency.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- PANASONIC INTELLECTUAL PROPERTY MANAGEMENT CO LTD
- Filing Date
- 2024-11-29
- Publication Date
- 2026-06-10
Smart Images
Figure 2026095147000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a washing machine.
Background Art
[0002] Patent Document 1 discloses a washing machine that suppresses the generation of detergent foam generated during washing. Patent Document 1 discloses a washing machine including an outer tub, a rotary drum rotatably disposed in the outer tub, drainage means for draining the washing water in the outer tub, foam detection means composed of two pairs of electrodes, and control means for a washing sequence. In Patent Document 1, when detergent foam is detected by the first electrode, the washing machine shifts to a weak washing sequence, and when detergent foam is detected by the second electrode, where it is more difficult for the detergent foam to reach than the first electrode, the washing machine shifts to an even weaker washing sequence. Then, if no detergent foam is detected by the second electrode after a predetermined time, the washing machine shifts to a normal washing sequence, and if detergent foam is detected by the second electrode, the drainage means is driven to drain water from the outer tub.
Prior Art Documents
Patent Documents
[0003]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0004] The present disclosure provides a washing machine capable of reducing the influence of detergent foam during dehydration after the washing process.
Means for Solving the Problems
[0005] The washing machine in this disclosure comprises a housing, a water tank elastically supported so as to be swingable within the housing, a rotating drum rotatably enclosed within the water tank, a water supply path for supplying water to the water tank, a water supply valve for opening and closing the water supply path, a drainage path for draining water from the water tank, a drainage valve for opening and closing the drainage path, a foam detection unit for detecting the generation of detergent foam in the water tank or the rotating drum, a foam volume detection unit for detecting the amount of the detergent foam, a water supply valve control unit for controlling the water supply valve, and a drainage valve control unit for controlling the drainage valve. The washing machine comprises a valve control unit and a water level control unit that controls the water level in the water tank, and performs a washing operation that includes at least a washing operation, a rinsing operation and a spin-drying operation. If the foam detection unit detects the generation of detergent foam during the washing process in the washing operation, it performs a first defoaming operation before the start of a first spin-drying operation that follows the washing process. If the amount of foam detected by the foam amount detection unit is greater than or equal to a predetermined value, it performs a second defoaming operation after the completion of the first defoaming operation and before the start of the first spin-drying operation. [Effects of the Invention]
[0006] The washing machine in this disclosure can reduce the influence of detergent foam on the spin-drying process after the washing cycle. [Brief explanation of the drawing]
[0007] [Figure 1] Schematic diagram showing a side cross-section of a drum-type washing machine and dryer in Embodiment 1. [Figure 2] Block diagram showing the control configuration of a drum-type washing machine and dryer in Embodiment 1. [Figure 3] A schematic diagram showing the relationship between the submerged electrode, the first electrode, the second electrode, and the detergent foam of the foam detection unit in Embodiment 1. [Figure 4] This figure shows the time evolution of the resistance value between the submerged electrode and the first electrode of the bubble detection unit in Embodiment 1, and the resistance value between the submerged electrode and the second electrode of the bubble detection unit in Embodiment 1. [Figure 5] A flowchart showing an example of the washing process of a drum-type washer-dryer in Embodiment 1. [Figure 6]Flowchart showing the processing of the washing step in the washing operation of the control device of a drum-type washing machine and dryer in Embodiment 1. [Figure 7] Flowchart showing the first rinse cycle process of the control device for a drum-type washing machine and dryer in Embodiment 1. [Figure 8] A schematic diagram showing the relationship between the amount of detergent foam, the concentration of the detergent solution, and the state of the water tank at the end of the washing process in Embodiment 1. [Figure 9] In Embodiment 1, a schematic diagram comparing the cases where the detergent solution concentration is high and low at the end of the washing process is shown, illustrating an example of the state of detergent foam and detergent solution in the water tank at the end of washing, during drainage, and at the detection timing in the first defoaming process. [Figure 10] In Embodiment 1, a schematic diagram comparing the cases where the amount of detergent foam at the end of the washing process is small and large, showing an example of the state of detergent foam and detergent solution in the water tank at the end of washing, during drainage, and at the detection timing in the first defoaming process. [Figure 11] A diagram showing the change in water level over time in Embodiment 1. [Figure 12] A schematic diagram showing an example of the state of detergent foam and detergent solution in the water tank before and after the second defoaming step in Embodiment 1. [Modes for carrying out the invention]
[0008] (Knowledge and other information that formed the basis of this disclosure) At the time the inventors conceived of this disclosure, washing machines had measures in place to address the detergent foam generated during the washing process. These measures included washing with a gentle force to prevent the generation of large amounts of detergent foam, and, if detergent foam still occurred, draining the water and ending the washing process. By the way, in a washing machine, a first spin-drying process is performed after the washing process. For example, in the rinsing cycle, a first spin-drying process is performed before the rinsing process to reduce the amount of detergent solution in the water tank. During this spin-drying process, detergent foam can create rotational resistance in the high-speed rotating drum, which may lead to insufficient spin-drying. However, we have discovered that conventional washing machines have inadequate countermeasures against detergent foam during spin-drying, and in order to solve this problem, we have come to form the subject of this disclosure. Therefore, this disclosure provides a washing machine that can reduce the influence of detergent foam on the first dehydration step performed after the washing step.
[0009] The embodiments will be described in detail below with reference to the drawings. However, unnecessary details may be omitted. For example, detailed explanations of already well-known matters or redundant explanations of substantially identical configurations may be omitted. This is to avoid the following explanation becoming unnecessarily verbose and to facilitate understanding for those skilled in the art. The attached drawings and the following description are provided to enable those skilled in the art to fully understand this disclosure and are not intended to limit the subject matter described in the claims.
[0010] (Embodiment 1) Embodiment 1 will be described below with reference to Figures 1 to 11.
[0011] [1-1. Structure] [1-1-1. Washing machine configuration] Figure 1 is a schematic diagram showing a side cross-section of the drum-type washing machine 1 in Embodiment 1. Figure 1 corresponds to a cross-section along the rotation axis 17 of the drum-type washing machine 1. In this specification, when front, back, up, and down are used with respect to the drum-type washer-dryer 1, the directions indicated by the arrows FR, RE, UP, and DO in each figure correspond to the front, back, up, and down of the drum-type washer-dryer 1. The front of the drum-type washer-dryer 1 may also be referred to as the front, and the rear of the drum-type washer-dryer 1 may also be referred to as the back.
[0012] As an example of a washing machine, a drum-type washing and drying machine 1 has a washing machine main body (housing) 10 composed of a frame member and an exterior member. In the washing machine main body 10, a water tank (outer tub) 11 is supported so as to be swingable. The water tank 11 is vibration-proof supported by a vibration-proof member 12 or the like below the washing machine main body 10.
[0013] Inside the water tank 11, a bottomed cylindrical rotating drum (rotating tub, inner tub) 13 is provided rotatably. The rotating drum 13 of the present embodiment is inclined such that the rotation center axis becomes lower as it proceeds from the front side to the back side. A large number of water passing holes 13a are formed on the entire outer peripheral surface of the rotating drum 13. On the inner wall surface of the rotating drum 13, a plurality of protruding plates 14 for stirring clothes are provided. An opening 15 is provided on the front side of the water tank 11 and the rotating drum 13. The opening 15 is covered by a lid 16 so as to be freely opened and closed. The user can take in and out the clothes C into and from the rotating drum 13 through the opening 15 by opening the lid 16.
[0014] A rotating shaft 17 is provided on the back surface of the rotating drum 13. The rotating shaft 17 coincides with the central axis of the water tank 11. A drum motor (driving means) 18 is connected to the rotating shaft 17. The drum motor 18 is attached to the back surface of the water tank 11. The drum motor 18 is composed of a DC brushless motor or the like. The drum motor 18 is controlled to rotate forward and backward and to have a variable rotation speed by a control device 100, a driving circuit (not shown), and the like. Further, the load applied to the drum motor 18, that is, the amount of the clothes C, is input to the control device 100 by a signal from a current detection circuit (not shown).
[0015] Above the water tank 11, a water supply path 20 is provided. The water supply path 20 is connected to, for example, a faucet not shown. A water supply valve 21 is provided in the water supply path 20. By opening and closing the water supply valve 21, water can be supplied into the water tank 11 through the water supply path 20. Thereby, a predetermined amount of water W is stored in the water tank 11. On the water tank 11, an upper surface of the water W corresponding to the shape of the water tank 11, that is, a water level surface L is formed. Thereby, washing becomes possible. Hereinafter, the water level surface L may be simply referred to as a water level L. A drainage path 30 is provided at the bottom of the water tank 11. A drain valve 31 is connected to the other end of the drainage path 30. By opening and closing the drain valve 31, the laundry water in the water tank 11 can be drained.
[0016] A hot air supply path 40 is provided around the water tank 11. The hot air supply path 40 in this embodiment includes a supply duct 41 extending from an intake port 41a provided on the outer surface of the washing machine body 10 to a hot air supply port 41b located above the rear of the water tank 11, and an exhaust duct 42 extending from a hot air outlet 42a at the top of the water tank 11 to an exhaust port 42b provided on the outer surface of the washing machine body 10.
[0017] In detail, the supply duct 41 has an upstream supply duct 41c extending from the intake port 41a. A heater 43 is located in the upstream supply duct 41c. A fan unit 44, which forms a flow path, is connected to the downstream end of the upstream supply duct 41c. The fan unit 44 is connected to a downstream supply duct 41d extending to the hot air outlet 41b. A filter 45 is positioned in the exhaust duct 42 to collect lint, dust, and other debris from inside the rotating drum 13.
[0018] A hot air supply path 40 is formed by a supply duct 41 and an exhaust duct 42. In the hot air supply path 40, hot air is introduced into the water tank 11 and the rotating drum 13 from the hot air outlet 41b in the direction of arrow A0, heating the air inside the rotating drum 13 and the water tank 11 to dry the clothes C.
[0019] A supply duct 41 extending from the back of the water tank 11 is equipped with a first electrode 91 and a second electrode 92 as a bubble detection means. In addition, a submerged electrode 90 is provided near the lower back of the water tank 11. The submerged electrode 90 is located below the waterline L and is submerged during the washing or rinsing process. The submerged electrode 90 and the first electrode 91 constitute the first bubble detection means SN1 (see Figure 4). The submerged electrode 90 and the second electrode 92 constitute the second bubble detection means SN2 (see Figure 4).
[0020] An air trap 46 is formed at the lower rear of the water tank 11, which communicates with the drainage path 30. An upward-extending tube 47 is connected to the air trap 46. The tube 47 is filled with air. The tube 47 extends above the rotating drum 13. A water level sensor 48, which acts as a pressure sensor, is positioned at the upper end of the tube 47. The water level sensor 48 detects the water level in the water tank 11 by detecting the air pressure inside the tube 47. That is, because the water pressure in the drainage path 30 changes according to the water level in the water tank 11, the air pressure inside the tube 47 also changes via the drainage path 30. Therefore, the water level can be detected by detecting the change in air pressure inside the tube 47.
[0021] A control device 100 is provided on the lower front side of the washing machine body 10.
[0022] [1-1-2. Configuration of the washing machine control device] Figure 2 is a block diagram showing the control configuration of the drum-type washing machine 1 in Embodiment 1. The control device 100 includes a processor 110 such as a CPU (Central Processing Unit) or MPU (Micro Processing Unit), memory 120, and interface circuits to which sensors are connected.
[0023] Memory 120 is a memory that stores programs and data. Memory 120 stores the control program 121 and various information necessary for the washing operation. Memory 120 has a non-volatile storage area. Alternatively, memory 120 may also have a volatile storage area and constitute the work area of the processor 110. Memory 120 is composed of, for example, ROM (Read Only Memory) or RAM (Random Access Memory).
[0024] [1-1-2-1. Signal input elements connected to the control device] The control device 100 is connected to an operation panel 131, a water level sensor 48, and a foam detection unit 133.
[0025] The control panel 131 has a display panel 132 that displays settings such as the driving course. When a driving course is selected and entered by the user, the control panel 131 inputs that information to the control device 100.
[0026] The water level sensor 48 is a pressure sensor. The water level sensor 48 is composed of, for example, a diaphragm that deforms due to air pressure and a strain sensor. The water level sensor 48 detects that water supply is complete when the pressure rises and detects a predetermined pressure. The water level sensor 48 also detects that drainage is complete when the pressure falls and detects a predetermined pressure. In addition, during dewatering, the water level sensor 48 detects when the water level remains low and does not fluctuate.
[0027] The foam detection unit 133 includes a submerged electrode 90, a first electrode 91, and a second electrode 92, and detects the detergent foam B described later based on the conductivity state of the submerged electrode 90, the first electrode 91, and the second electrode 92.
[0028] Figure 3 is a schematic diagram showing the relationship between the submerged electrode 90, the first electrode 91, the second electrode 92, and the detergent foam B of the foam detection unit 133 in Embodiment 1. Figure 4 is a diagram showing the time change of the resistance values between the submerged electrode 90 and the first electrode 91 of the foam detection unit 133, and between the submerged electrode 90 and the second electrode 92 of the foam detection unit 133 in Embodiment 1. In the following explanation, "detergent solution" refers to water in which detergent is dissolved. Furthermore, "detergent foam" refers to foam that is formed when air is incorporated into the detergent solution.
[0029] In the drum-type washer-dryer 1, during the washing process, the submerged electrode (foam detection means) 90 is immersed in the detergent solution D (see Figure 1). At this time, the detergent solution D containing detergent components is agitated by the rotation of the rotating drum 13, generating detergent foam B (see Figure 3). The detergent foam B generated in the water tank 11 enters the supply duct 41. At this time, abnormal foaming may occur, where a large amount of detergent foam B is generated. When abnormal foaming occurs, the submerged electrode 90 and the first electrode (foam detection means) 91 become electrically connected by the detergent foam B, etc. If the abnormal foaming progresses further, the submerged electrode 90 and the second electrode (foam detection means) 92 become electrically connected by the detergent foam B (see Figure 3), etc.
[0030] Here, the submerged electrode 90 and the first electrode 91 are connected to a resistance value determination circuit (not shown). The control device 100 detects the resistance between the submerged electrode 90 and the first electrode 91 and compares it with a reference resistance in the resistance value determination circuit. If the resistance value is high, it determines that there is no entry of detergent foam B due to abnormal foaming. That is, when the space between the submerged electrode 90 and the first electrode 91 is filled with detergent foam B, an energetic path is formed between the submerged electrode 90 and the first electrode 91 by the detergent foam B, and a low resistance value is detected. If the resistance value is less than a first threshold, the control device 100 determines that detergent foam B due to abnormal foaming is present. If the resistance value is equal to or greater than the first threshold, the control device 100 determines that detergent foam B due to abnormal foaming is not present. The first threshold of the resistance value determination circuit is, for example, 500 [kΩ].
[0031] The submerged electrode 90 and the second electrode 92 are connected to a resistance value determination circuit (not shown). The control device 100 detects the resistance between the submerged electrode 90 and the second electrode 92 and compares it with a reference resistance in the resistance value determination circuit. If the resistance value is high, it determines that there is no entry of detergent foam B due to abnormal foaming. That is, when the space between the submerged electrode 90 and the second electrode 92 is filled with detergent foam B, an energetic path is formed between the submerged electrode 90 and the second electrode 92 by the detergent foam B, and a low resistance value is detected. If the resistance value is less than the second threshold, the control device 100 determines that detergent foam B due to abnormal foaming is present. If the resistance value is equal to or greater than the second threshold, the control device 100 determines that detergent foam B due to abnormal foaming is not present. The second threshold of the resistance value determination circuit is, for example, 500 [kΩ].
[0032] [1-1-2-2. Signal output elements connected to the control device] The control device 100 is connected to controllable components such as the water supply valve 21, the drain valve 31, the drum motor 18 of the rotating drum 13, the heater 43, and the fan motor 44a of the fan unit 44.
[0033] By opening and closing the water supply valve 21, water can be supplied into the water tank 11 through the water supply path 20. The detergent solution D in the water tank 11 can be drained by opening and closing the drain valve 31. The drum motor 18 of the rotating drum 13 rotates the rotating drum 13 in both forward and reverse directions. The heater 43 generates heat and produces warm air in the warm air blowing path 40. The fan motor 44a of the fan unit 44 generates airflow in the direction of arrow A0 (see Figure 1) within the hot air delivery path 40.
[0034] [1-1-2-3. Functional parts of the control device] The processor 110 includes a water supply valve control unit 111, a drain valve control unit 112, a water level control unit 113, a drum control unit 114, a heater control unit 115, a fan unit control unit 116, and an operation control unit 117. The water supply valve control unit 111, the drain valve control unit 112, the water level control unit 113, the drum control unit 114, the heater control unit 115, the fan unit control unit 116, and the operation control unit 117 are functional units configured by software. The water supply valve control unit 111, the drain valve control unit 112, the water level control unit 113, the drum control unit 114, the heater control unit 115, the fan unit control unit 116, and the operation control unit 117 are configured by the processor 110 executing a control program.
[0035] The water supply valve control unit 111 controls the opening and closing of the water supply valve 21. The drain valve control unit 112 controls the opening and closing of the drain valve 31. The water level control unit 113 controls the water level based on the detection results of the water level sensor 48. The water level control unit 113 controls the water level in the water tank 11 via the water supply valve control unit 111 and the drain valve control unit.
[0036] The drum control unit 114 controls the drum motor 18 to control the rotation of the rotating drum 13. The heater control unit 115 controls the heat generation of the heater 43. The fan unit control unit 116 controls the fan motor 44a to control the airflow within the hot air delivery path 40.
[0037] The operation control unit 117 controls the operation of the drum-type washer-dryer 1. Based on the input signal from the operation panel 131 indicating the start of operation, the operation control unit 117 controls each part of the drum-type washer-dryer 1 via the water supply valve control unit 111, the drain valve control unit 112, the water level control unit 113, the drum control unit 114, the heater control unit 115, the fan unit control unit 116, and so on. Specifically, when the operation control unit 117 receives an input signal from the operation panel 131 indicating the start of operation, it acquires data from the water level detection means that detects the water level in the water tank 11 and operates the water supply valve 21, the drain valve 31, the heater 43, the fan unit 44, etc. via a load driving means (not shown), controls the drum motor 18 via a drive circuit (not shown), and controls the washing operation of the drum-type washer-dryer 1, such as the washing, rinsing, spinning, and drying processes.
[0038] The machine performs a series of processes including washing, rinsing, spinning, and drying.
[0039] [1-2. Operation] The operation of the drum-type washer-dryer 1, configured as described above, will be explained below.
[0040] Figure 5 is a flowchart showing an example of the washing operation process of the drum-type washer-dryer 1 in Embodiment 1. The washing operation shown in Figure 5 illustrates the operation mode in which the drying process is not performed. The control device 100 causes the drum-type washer-dryer 1 to perform a washing operation. When the washing operation is started, in step S11, the control device 100 causes the drum-type washer-dryer 1 to perform a wash operation. The wash operation includes a water supply step and a washing step.
[0041] In step S12, the control device 100 causes the drum-type washing and drying machine 1 to perform a first rinse cycle. The first rinse cycle includes a draining step, a spin-drying step, a water supply step, and a rinsing step. In step S13, the control device 100 causes the drum-type washing and drying machine 1 to perform a second rinse cycle. The second rinse cycle includes a draining step, a spin-drying step, a water supply step, and a rinsing step. In step S14, the control device 100 causes the drum-type washing and drying machine 1 to perform a spin-drying operation. The spin-drying operation includes a draining step and a spin-drying step.
[0042] [1-2-1. Washing Process Operations] Figure 6 is a flowchart showing the processing of the washing step of the washing operation of the control device 100 of the drum-type washing and drying machine 1 in Embodiment 1. When the washing process is started, the control device 100 determines in step S101 whether the resistance value based on the submerged electrode 90 and the first electrode 91 is less than a first threshold. If the control device 100 determines that the resistance value based on the submerged electrode 90 and the first electrode 91 is less than the first threshold (step S101: Yes), it proceeds to step S104. If the control device 100 determines that the resistance value based on the submerged electrode 90 and the first electrode 91 is greater than or equal to a first threshold (step S101: No), it proceeds to step S102.
[0043] In step S102, the control device 100 determines that there is no detergent foam B due to abnormal foaming between the submerged electrode 90 and the first electrode 91, and starts or continues the normal washing sequence. Here, the normal washing sequence is, for example, operating the rotating drum 13 at a rotation speed of 45 [r / min] with an agitation time of 12 seconds followed by a 1-second pause.
[0044] In step S103, the control device 100 determines whether a predetermined time has elapsed since the start of the washing process. This predetermined time is, for example, 15 minutes. If the control device 100 determines that a predetermined time has elapsed (step S103: Yes), it terminates the washing process. If the control device 100 determines that a predetermined time has not elapsed (step S103: No), it returns to the process in step S101.
[0045] In step S104, the control device 100 determines that abnormal foaming has occurred and proceeds to the process in step S105. In step S105, the control device 100 proceeds to the first gentle wash sequence. That is, the control device 100 starts or continues the first gentle wash sequence in the drum-type washer-dryer 1. Then, the control device 100 proceeds to the process in step S106. Here, the first gentle wash sequence is, for example, operating the rotating drum 13 at a rotation speed of 35 [r / min] with a weak agitation time of 10 seconds followed by a 5-second pause. Because the agitation in the first gentle wash sequence is weaker than in the normal wash sequence, foaming can be suppressed.
[0046] In step S106, the control device 100 determines whether the resistance value based on the submerged electrode 90 and the second electrode 92 is less than the second threshold. If the control device 100 determines in step S106 that the resistance value based on the submerged electrode 90 and the second electrode 92 is less than the second threshold (step S106: Yes), it proceeds to step S108. If the control device 100 determines that the resistance value based on the submerged electrode 90 and the second electrode 92 is greater than or equal to the second threshold (step S106: No), it proceeds to step S103a.
[0047] In step S103a, the control device 100 determines whether a predetermined time has elapsed since the start of the washing process. This predetermined time is, for example, 15 minutes. If the control device 100 determines that a predetermined time has elapsed (step S103a: Yes), it terminates the washing process. If the control device 100 determines that a predetermined time has not elapsed (step S103a: No), it proceeds to the process in step S107.
[0048] In step S107, the control device 100 determines whether a predetermined time has elapsed since the start of the first weak washing sequence. If the control device 100 determines that a predetermined time has elapsed (step S107: Yes), it returns to the process in step S101. If the control device 100 determines that a predetermined time has not elapsed (step S107: No), it returns to the process in step S105.
[0049] In step S108, the control device 100 determines that abnormal foaming has progressed and proceeds to the process in step S109. In step S109, the control device 100 performs a defoaming process based on the second foam detection means SN2 (see Figure 4) and returns to the process in step S101.
[0050] As described above, in the drum-type washer-dryer 1, when the washing process starts, foam detection is initiated based on the resistance value between the submerged electrode 90 and the first electrode 91 (step S101). If no detergent foam B is detected at this time, steps S101, S102, and S103 are repeated, and the normal washing sequence is executed for a predetermined time.
[0051] During the normal washing sequence, if the resistance value between the submerged electrode 90 and the first electrode 91 falls below a first threshold (step S101: Yes), it is determined that abnormal foaming has occurred (step S104), and the process moves to a first weak washing sequence (step S105), in which the washing process is executed to suppress foaming. At this time, if no further progression of detergent foam B is detected, the first weak washing sequence is executed for a predetermined time (step S107).
[0052] During the first weak washing sequence, if the resistance value between the submerged electrode 90 and the second electrode 92 falls below the second threshold, it is determined that abnormal foaming has progressed further (step S108), and a defoaming process based on the second foam detection means SN2 (see Figure 4) is executed, returning to the processing at the start of the washing process.
[0053] [1-2-2. Rinse Operation] Figure 7 is a flowchart showing the first rinse cycle process of the control device 100 of the drum-type washing machine 1 in Embodiment 1. The control device 100 starts the first rinse cycle when the washing cycle is completed. In other words, when the washing cycle is completed, the control device 100 causes the drum-type washing and drying machine 1 to perform the first rinse cycle. In step S200, the control device 100 performs a drainage process. That is, the control device 100 opens the drain valve 31 and waits for a predetermined time until the detergent solution D is drained from the water tank 11.
[0054] In step S201, the control device 100 determines whether or not abnormal foaming has occurred during the washing process. Specifically, in step S101 of Figure 6, the control device 100 determines whether or not the resistance value based on the submerged electrode 90 and the first electrode 91 has fallen below a first threshold. If the control device 100 determines that abnormal foaming has occurred (step S201: Yes), it proceeds to step S202. If the control device 100 determines that no abnormal foaming has occurred (step S201: No), it proceeds to step S218.
[0055] If a large amount of detergent foam B is generated during the washing process and detected (Yes in step S101 in Figure 6, step S201 in Figure 7), detergent foam B may remain in the water tank 11 at the end of the washing process. Therefore, even after draining (step S200), detergent foam B is likely to remain in the water tank 11, and if dewatering is performed in this state, the detergent foam B may become a rotational resistance of the rotating drum 13, resulting in insufficient dewatering. Therefore, in this embodiment, a first defoaming process (steps S202 to S209) is performed before dewatering.
[0056] In step S202, the control device 100 starts the first defoaming process. The detergent foam B generated during the washing process is dense and contains a lot of water. Therefore, the detergent foam B generated during the washing process easily transforms naturally into detergent solution D over time. Thus, in the first defoaming step, the goal is to efficiently drain the detergent solution D, which has naturally transformed from detergent foam B.
[0057] In step S203, the control device 100 drives the drum motor 18 with a first defoaming rotation. Specifically, as the first defoaming rotation, the control device 100 operates the rotating drum 13 at a rotation speed of 30 [r / min] with an agitation time of 3 seconds followed by a 12-second pause. This creates a water flow in the water tank 11, making it easier to flush the detergent solution D.
[0058] In step S204, the control device 100 closes the drain valve 31. By closing the drain valve 31, the detergent foam B is converted into detergent solution D, and detergent solution D tends to accumulate in the tank 11. Therefore, when the drain valve 31 is opened next, the detergent solution D is more easily drained.
[0059] In step S205, the control device 100 determines whether or not it is time to detect the amount of foam. In this embodiment, the timing for detecting the amount of foam is predetermined to be the timing when the drain valve is closed for the second time after the start of the first defoaming process. Therefore, in this embodiment, the control device 100 determines whether or not the drain valve has been closed for the second time after the start of the first defoaming process. If the control device 100 determines that it is time to detect the amount of foam (step S205: Yes), it proceeds to the process in step S206. If the control device 100 determines that it is not the timing to detect the amount of foam (step S205: No), it proceeds to the process in step S207.
[0060] In step S206, the amount of foam is detected and stored in the memory 120. In this embodiment, the control device 100 detects the water level using the water level sensor 48 and stores it in the memory 120. In this embodiment, the water level sensor 48 corresponds to the foam amount detection unit. In step S207, the control device 100 opens the drain valve 31.
[0061] In step S208, the control device 100 determines whether the operation of the first defoaming process, specifically the process from steps S203 to S207, has been repeated a predetermined number of times. In this embodiment, the predetermined number of times is set to 6. Therefore, the control device 100 determines whether the process from steps S203 to S207 has been repeated 6 times. If the control device 100 determines that the operation of the first defoaming process has been repeated a predetermined number of times (step S208: YES), it proceeds to the process in step S209. If the control device 100 determines that the operation of the first defoaming process has not been repeated a predetermined number of times (step S208: No), it returns to the process in step S203.
[0062] In step S209, the control device 100 completes the first defoaming process.
[0063] In step S210, the control device 100 determines whether the detected amount of foam is greater than or equal to a predetermined value. In this embodiment, the control device 100 determines whether the amount of change in water level is greater than or equal to a predetermined value. If the control device 100 determines that the detected amount of foam is equal to or greater than a predetermined value (step S210: Yes), it proceeds to the process in step S211. If the control device 100 determines that the detected amount of foam is not above a predetermined value (step S210:N0), it proceeds to the process in step S218. In other words, if the control device 100 determines that the detected amount of foam is not above a predetermined value, it omits the execution of the second defoaming process.
[0064] In step S211, the control device 100 starts a second defoaming process. The second defoaming process is performed when the amount of detergent foam B has been reduced to an undetectable level by the first electrode 91, and the washing process has been completed successfully, but the amount of foam remaining after the first defoaming process is above a predetermined value.
[0065] In step S212, the control device 100 drives the drum motor 18 with a second defoaming rotation. Specifically, the control device 100 operates the rotating drum 13 at a rotation speed of 45 [r / min] with a stirring time of 12 seconds followed by a 1-second pause as the second defoaming rotation. This makes it easier for large detergent foam B, which is filled with air, to be crushed into fine, small detergent foam B. In other words, it makes it easier to increase the fluidity of the detergent foam B, resulting in what is known as creamy detergent foam B. In step S213, the control device 100 closes the drain valve 31. In step S214, the control device 100 opens and closes the water supply valve 21 to supply a predetermined amount of water to the water tank 11. The predetermined amount of water supplied is enough to immerse the clothing C inside the water tank 11.
[0066] In step S215, the control device 100 determines whether a predetermined time has elapsed since the clothing C was submerged in water. The predetermined time is, for example, 20 seconds. If the control device 100 determines that a predetermined time has elapsed since the clothing C was submerged in water (step S215: Yes), it proceeds to step S216. If the control device 100 determines that a predetermined time has not elapsed since the clothing C was submerged in water (step S215: No), it repeats the process in step S215. In step S216, the control device 100 performs a drainage process. In step S216, similar to step S200, the control device 100 performs a drainage process by opening the drain valve 31, etc.
[0067] In step S217, the control device 100 completes the second defoaming process.
[0068] In step S218, the control device 100 performs a dewatering process. In step S219, the control device 100 executes the water supply process. In step S220, the control device 100 performs a rinsing process. The control device 100 then causes the drum-type washing and drying machine 1 to complete the first rinse cycle.
[0069] Note that in the flowchart shown in Figure 7, steps S202, S209, S211, and S217 may be omitted. Also, in the flowchart shown in Figure 7, steps S205 and S208 are provided to explain a configuration in which it is determined whether or not it is the foam detection timing, and whether or not the predetermined processing of the first defoaming process has been repeated a predetermined number of times, but these may also be omitted. In other words, the processing of the first defoaming process may be defined sequentially and processed in order. For example, if the drain valve 31 is closed for the second time, the process may be to detect the amount of foam without determining whether or not the drain valve 31 has been closed for the second time.
[0070] Figure 8 is a schematic diagram showing the relationship between the amount of detergent foam B, the concentration of detergent solution D, and the state of the water tank 11 at the end of the washing process. In Figures 8 and beyond, clothing C with a high concentration of detergent solution D is shown with a dense dot pattern, while clothing C with a low concentration of detergent solution D is shown with a sparse dot pattern.
[0071] The amount of detergent foam B at the end of the washing process and the concentration of detergent solution D contained in clothing C vary depending on the washing conditions and the process during the washing cycle, and are therefore not uniformly determined. In other words, the amount of detergent foam B before the start of the spin-drying process after the washing process varies depending on the washing conditions and the process during the washing cycle, and is therefore not uniformly determined. Washing conditions refer to settings such as the amount of clothing C, the type of clothing C, the amount of detergent, the type of detergent, the amount of dirt, the type of dirt, water temperature, water quality, operating course, or washing time. The process during the washing cycle refers to, for example, the presence or absence of a first weak washing sequence and the presence or absence of drainage based on a second foam detection means.
[0072] Therefore, in this embodiment, the system is designed to detect when a second defoaming step is necessary by making further determinations during the first defoaming step, in addition to considering the washing conditions and the process during the washing cycle. The following describes when a second defoaming step is necessary and when it is not.
[0073] Figure 8(o) shows the state of the water tank 11 at the end of the washing process when no abnormal foaming is detected during the washing process. In this state, the amount of detergent foam B is small and the concentration of detergent solution D contained in the clothing C is low. In this case, even if a spin-drying process is performed after the washing process, it is unlikely that a large amount of detergent foam B will be generated during the spin-drying process, so the first defoaming process is not required after the draining process following the washing process. Therefore, the first defoaming process is not performed during the rinsing operation.
[0074] The conditions inside the water tank 11 shown in Figures 8(q), (r), and (s) represent the state of the water tank 11 when the first defoaming step is performed during the rinsing operation. In the state inside the water tank 11 shown in Figure 8(s), the concentration of detergent solution D contained in the clothing C is higher compared to Figure 8(q). Also, in the state inside the water tank 11 shown in Figure 8(s), the amount of detergent foam B is greater compared to Figure 8(r).
[0075] Figure 9 is a schematic diagram showing an example of the state of detergent foam B and detergent solution D in the water tank 11 at the end of washing, at the time of draining, and at the detection timing in the first defoaming step, comparing the case where the concentration of detergent solution D is high and the case where it is low in Embodiment 1. Figures 9(q) and 9(s) show the same conditions inside tank 11 as in Figures 8(q) and 8(s), respectively.
[0076] Figure 9(q) shows the state inside the water tank 11, where abnormal foaming was determined to have occurred during the washing process, and at the end of the washing process, the amount of detergent foam B is large, but the concentration of detergent solution D contained in the clothes is low. When the concentration of detergent solution D contained in the clothes C is low, the amount of detergent foam B decreases during the drainage process after the washing process. Therefore, as shown in Figure 9(q-2), the amount of detergent foam B in the water tank 11 becomes small when the drainage process after the washing process is completed. Consequently, as shown in Figure 9(q-3), the amount of detergent foam B that changes into detergent solution D in the first defoaming process is small.
[0077] Figure 9(s) shows the state inside the water tank 11, indicating that abnormal foaming occurred during the washing process, and that at the end of the washing process, the amount of detergent foam B is large and the concentration of detergent solution D contained in the clothes is high. In this case, as shown in Figure 9(s-2), even after the drainage process following the washing process is completed, the amount of detergent foam B in the water tank 11 does not become small. Therefore, as shown in Figure 9(s-3), during the execution of the first defoaming process, a large amount of detergent foam B is converted into detergent solution D, causing a significant change in the water level.
[0078] Figure 10 is a schematic diagram showing an example of the state of detergent foam B and detergent solution D in the water tank 11 at the end of washing, during drainage, and at the detection timing in the first defoaming process, comparing the case where the amount of detergent foam B at the end of the washing process is small and the case where it is large, in Embodiment 1. Figures 10(r) and (s) show the same conditions inside tank 11 as in Figures 8(r) and (s), respectively. Figures 10(r) and 10(s) show the case where the concentration of detergent solution D in clothing C is similarly high.
[0079] The state inside the water tank 11 shown in Figure 10(r) indicates that abnormal foaming occurred during the washing process, but the amount of detergent foam B at the end of the washing process was not very large. In this case, as shown in Figure 10(r-2), the amount of detergent foam B in the water tank 11 becomes small when the drainage process after the washing process is completed. Therefore, as shown in Figure 10(r-3), the amount of detergent foam B that changes into detergent solution D in the first defoaming process is small.
[0080] Figure 10(s) shows the state inside the water tank 11, where abnormal foaming was detected during the washing process, and the amount of detergent foam B remains high even at the end of the washing process. In this case, as shown in Figure 10(s-2), the amount of detergent foam B in the water tank 11 does not decrease to a small amount even after the drainage process following the washing process is completed. Therefore, as shown in Figure 10(s-3), a large amount of detergent foam B is converted into detergent solution D during the execution of the first defoaming process, causing a significant change in the water level L.
[0081] As shown in Figures 9 and 10, if the concentration of detergent solution D in clothing C is high and the amount of detergent foam B is large at the end of the washing process, detergent foam B will remain even after the first defoaming process is completed. If the dewatering process is carried out in this state, the detergent solution D contained in clothing C will turn into detergent foam B during dewatering, creating rotational resistance for the rotating drum 13, which may prevent proper dewatering. Therefore, in this embodiment, by detecting fluctuations in the water level L that exceed a predetermined value during the first defoaming process, a state in which there is a high probability that detergent foam B will remain after the completion of the first defoaming process is detected.
[0082] Figure 11 shows the change in water level L over time in Embodiment 1. In Figure 11, the horizontal axis represents the elapsed time of the first defoaming process, and the vertical axis represents the water level L. In Figure 11, the solid line shows the change in water level L when the change in water level L is large in the first defoaming process. Also in Figure 11, the dashed line shows the change in water level L in the case of detergent foam B where the change in water level L is small in the first defoaming process. The solid line corresponds to state (s) in Figure 8, and the dashed line corresponds to states (q) and (r) in Figure 8. In this embodiment, in the first defoaming step, when the drain valve 31 is closed for the second time, a determination is made as to whether or not there is a large amount of foam based on the water level L detected by the water level sensor 48.
[0083] When the drain valve 31 is closed, the detergent solution D, which has changed from detergent foam B, accumulates in the water tank 11, making it possible to detect the water level L in the water tank 11. As shown in Figure 11, when the drain valve 31 is closed for the first time, the water level L is unstable and prone to change regardless of the amount of foam. Therefore, it is not suitable for accurately detecting the amount of foam. On the other hand, when the drain valve 31 is closed for the third time or later, the detergent solution D is discharged to some extent, so the water level L stabilizes regardless of the concentration of the detergent solution D.
[0084] Therefore, in this embodiment, the timing for detecting the amount of foam is set to occur when the drain valve 31 is closed for the second time. More specifically, the timing for detecting the amount of foam is set to occur just before the drain valve 31 is opened after it has been closed for the second time. If the water level L detected at this timing is above a predetermined value, it is determined that a large amount of foam has been generated (steps S205, S206).
[0085] Figure 12 is a schematic diagram showing an example of the state of detergent foam B and detergent solution D in the water tank 11 before and after the second defoaming process in Embodiment 1. As shown in Figure 12(s-4), the detergent foam B remaining after the first defoaming step has less water content and lower foam density compared to the detergent foam B generated in the washing step. Therefore, in the second defoaming step after the first defoaming step, the rotating drum 13 is rotated vigorously with the drain valve 31 open (step S212). This makes it easier to crush the large, air-filled detergent foam B into finer, smaller detergent foam B, as shown in Figure 12(s-5). In other words, by making the detergent foam B creamy and increasing its fluidity, it is made easier to drain through the drainage path 30.
[0086] Furthermore, in the second defoaming step, since it is determined that the clothing C contains a highly concentrated detergent solution D, a predetermined amount of water may be supplied (step S214) and a predetermined time may be waited (step S215), as shown in Figure 12(s-6). This allows the detergent solution D contained in the clothing C to be diluted, as shown in Figure 12(s-7), and also makes it easier to induce detergent foam B in the water tank 11 into the detergent solution D. Therefore, by draining the detergent solution D after a predetermined time, it is easier to eliminate the residual detergent foam B in the water tank 11, and as shown in Figure 12(s-8), the concentration of detergent solution D contained in the clothing C can also be lowered. Therefore, when the drain valve 31 is opened, the detergent solution D is more easily drained. Thus, even if it is determined that a large amount of detergent foam B is generated and the concentration of detergent solution D contained in the clothing C is high, after the completion of the second defoaming step, the detergent foam B in the water tank 11 is more easily eliminated, making it easier to dewater the clothing C when performing the dewatering step (step S218). Therefore, the rinsing process can be performed efficiently (step S220).
[0087] [1-3. Effects, etc.] As described above, in this embodiment, the drum-type washer-dryer 1 includes a washing machine body 10, a water tank 11 elastically supported so as to be swingable within the washing machine body 10, a rotating drum 13 rotatably enclosed within the water tank 11, a water supply path 20 for supplying water to the water tank 11, a water supply valve 21 for opening and closing the water supply path 20, a drainage path 30 for draining water from the water tank 11, a drainage valve 31 for opening and closing the drainage path 30, a foam detection unit 133 for detecting the generation of detergent foam B in the water tank 11 or the rotating drum 13, a water level sensor 48 as a foam amount detection unit for detecting the amount of detergent foam B, and a control for the water supply valve 21. The washing machine includes a water supply valve control unit 111, a drain valve control unit 112 that controls the drain valve 31, and a water level control unit 113 that controls the water level L in the water tank 11. The machine performs a washing operation that includes at least a wash operation, a rinse operation, and a spin-drying operation. If the foam detection unit 133 detects the generation of detergent foam B during the washing process in the washing operation, it performs a first defoaming process before the start of the first spin-drying process which is performed after the washing process in the washing operation. If the amount of foam detected by the water level sensor 48 is greater than or equal to a predetermined value, it performs a second defoaming process after the completion of the first defoaming process and before the start of the first spin-drying process. This configuration makes it possible to provide a drum-type washer-dryer 1 that can reduce the influence of detergent foam B during the spin-drying process after the washing cycle.
[0088] As in this embodiment, in the first defoaming step, water is not supplied by the water supply valve control unit 111, and the second defoaming step may be executed only if the amount of foam in the first defoaming step is equal to or greater than a predetermined value. With this configuration, by not supplying water, the water tank 11 is not affected by water supply, and the amount of foam in the water tank 11 can be detected accurately in the first defoaming process.
[0089] As in this embodiment, in the second defoaming step, water may be supplied until the clothing C in the water tank 11 is submerged, and then left for a predetermined time. With this configuration, the detergent solution D contained in the clothing C can be diluted with water. Therefore, when draining, the detergent solution D can be easily drained from the water tank 11, and when spinning, the transformation of the detergent solution D contained in the clothing C into detergent foam B can be suppressed.
[0090] As in this embodiment, if the amount of foam in the first defoaming step is less than a predetermined value, only the first defoaming step may be performed. With this configuration, if it is determined that detergent foam B is unlikely to be generated, the second defoaming step, which would be an excessive defoaming step, is not performed, making it easier to achieve a necessary and sufficient washing cycle.
[0091] As in this embodiment, the foam volume detection unit may be a water level sensor 48, and the amount of detergent foam B may be detected based on the water level L in the water tank 11. With this configuration, the amount of foam can be detected using the water level sensor installed in the washing machine.
[0092] (Other embodiments) As described above, Embodiment 1 has been explained as an example of the technology disclosed in this application. However, the technology in this disclosure is not limited to this and can be applied to embodiments that have been modified, replaced, added, or omitted. Furthermore, it is possible to create new embodiments by combining the components described in Embodiment 1 above. Therefore, other embodiments are illustrated below.
[0093] In the above-described embodiment, the configuration of a drum-type washer-dryer 1 was explained as the washing machine, but this configuration may also be applied to a washing machine that omits the drying function.
[0094] In the embodiment described above, as an example of the washing operation of the drum-type washer-dryer 1, a configuration in which a second rinse operation is performed after a first rinse operation was explained as shown in Figure 5. However, the washing operation of the drum-type washer-dryer 1 is not limited to this. For example, the washing operation of the drum-type washer-dryer 1 does not have to include a second rinse operation. That is, the washing operation of the drum-type washer-dryer 1 may consist only of a wash operation, a rinse operation, and a spin-drying operation performed in order. In this case, the drum-type washer-dryer 1 may perform the "first rinse operation" described in [1-2-2] as the rinse operation.
[0095] In the embodiment described above, the case in which the control device 100 receives user operations on various screens displayed on the operation panel 131 was explained. However, the control device 100 may also receive user operations on various screens displayed on a smartphone, for example.
[0096] The processor 110 may consist of a single processor or multiple processors. These processors may also be hardware programmed to implement the corresponding functional units. That is, these processors may consist of, for example, an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).
[0097] The block diagram of the drum-type washing machine 1 shown in Figure 2 is merely an example, and the specific implementation is not particularly limited. In other words, it is not necessarily required that each part be individually equipped with corresponding hardware; it is also possible to configure the machine so that a single processor executes a program to realize the functions of each part. Furthermore, some of the functions realized by software in the above-described embodiment may be implemented as hardware, or some of the functions realized by hardware may be implemented as software.
[0098] The processing steps of the control device 100 shown in Figures 5 to 7 are divided according to the main processing content to facilitate understanding of the operation, and the operation is not limited by the way the processing units are divided or the names of the units. Depending on the processing content, it may be further divided into more steps. Alternatively, it may be divided so that one step unit includes even more processing. Furthermore, the order of the steps may be changed as appropriate, as long as it does not impede the intent of this disclosure.
[0099] Since the embodiments described above are for illustrative purposes of the technology described herein, various modifications, substitutions, additions, omissions, etc., can be made within the claims or their equivalents.
[0100] (Note) Based on the above description of embodiments, the following technologies are disclosed.
[0101] (Technology 1) A housing, a water tank elastically supported within the housing so as to be swingable, a rotating drum rotatably enclosed within the water tank, a water supply path for supplying water into the water tank, a water supply valve for opening and closing the water supply path, a drainage path for draining water from the water tank, a drainage valve for opening and closing the drainage path, a foam detection unit for detecting the generation of detergent foam in the water tank or the rotating drum, a foam volume detection unit for detecting the amount of detergent foam, a water supply valve control unit for controlling the water supply valve, and a drainage valve control unit for controlling the drainage valve. A washing machine comprising a water level control unit for controlling the water level in the water tank, which performs a washing operation including at least a wash operation, a rinse operation, and a spin-drying operation, and when the foam detection unit detects the generation of detergent foam during the washing process in the wash operation, it performs a first defoaming process before the start of a first spin-drying process performed after the washing process, and when the amount of foam detected by the foam amount detection unit is greater than or equal to a predetermined value, it performs a second defoaming process after the completion of the first defoaming process and before the start of the first spin-drying process. This configuration makes it possible to provide a washing machine that can reduce the impact of detergent foam during the spin-drying process after the washing cycle.
[0102] (Technical 2) The washing machine according to Technical 1, wherein in the first defoaming step, water is not supplied by the water supply valve control unit, and the second defoaming step is performed when the amount of foam in the first defoaming step is equal to or greater than a predetermined value. With this configuration, by not supplying water, the water tank is not affected by water supply, and the amount of foam in the tank can be accurately detected in the first defoaming process.
[0103] (Technology 3) The washing machine according to Technology 1 or 2, wherein in the second defoaming step, water is supplied until it is submerged in the clothes in the water tank and left for a predetermined time. This configuration allows the detergent solution contained in the clothes to be diluted with water. Therefore, it is possible to easily drain the detergent solution from the water tank during drainage, and it is possible to suppress the transformation of the detergent solution contained in the clothes into detergent foam during spin-drying.
[0104] (Technical 4) A washing machine according to any one of Technical 1 to 3, wherein if the amount of foam in the first defoaming step is less than a predetermined value, only the first defoaming step is performed. With this configuration, if it is determined that detergent foam is unlikely to be generated, the second defoaming step, which would be an excessive defoaming step, is not performed, making it easier to achieve a washing cycle that is just right.
[0105] (Technology 5) The washing machine according to any one of Technologies 1 to 4, wherein the foam volume detection unit is a water level sensor and detects the amount of detergent foam based on the water level in the water tank. With this configuration, the amount of foam can be detected using the water level sensor installed in the washing machine. [Industrial applicability]
[0106] This disclosure is suitably applicable to washing machines configured to generate detergent foam that creates rotational resistance during the spin-drying process. [Explanation of symbols]
[0107] 1. Drum-type washer-dryer (washing machine) 10. Washing machine body (casing) 11 Aquariums 12 components 13-speed drum 13a Water hole 14 Projection plate 15 Opening 16 Lid 17 Rotation axis 18 Drum motor 20 Water supply routes 21 Water supply valve 30 Drainage routes 31 Drain valve 40 Hot air blowing path 41 Supply duct 41a Intake 41b Hot air outlet 41c Upstream supply duct 41d Downstream supply duct 42 Exhaust duct 42a Wind outlet 42b Exhaust port 43 Heater 44 Fan Units 44a Fan motor 45 Filters 46 Air trap 47 Tubes 48. Water level sensor (bubble volume detection unit) 90 Submerged electrode 91 First electrode 92 Second electrode 100 Control device 110 processors 111 Water supply valve control unit 112 Drain valve control unit 113 Water Level Control Unit 114 Drum Control Unit 115 Heater control unit 116 Fan Unit Control Unit 117 Operation Control Unit 120 memory 121 Control Program 131 Control Panel 133 Bubble detection unit A0 Arrow B Detergent foam C Clothing SN1 First bubble detection means SN2 Second bubble detection means D Detergent solution L0 Draft surface (water level) W water
Claims
1. The casing and A water tank elastically supported within the housing so as to be able to swing, A rotating drum is rotatably enclosed within the aforementioned water tank, A water supply path for supplying water into the aforementioned water tank, A water supply valve that drives the water supply path to open and close, A drainage path for draining the water in the aforementioned tank, A drain valve that drives the drainage path to open and close, A foam detection unit for detecting the generation of detergent foam in the water tank or the rotating drum, A foam volume detection unit for detecting the amount of detergent foam, A water supply valve control unit that controls the water supply valve, A drain valve control unit that controls the drain valve, The system includes a water level control unit for controlling the water level in the water tank, At a minimum, perform a washing cycle that includes a wash cycle, a rinse cycle, and a spin cycle. If the foam detection unit detects the generation of detergent foam during the washing process in the washing operation, the first defoaming process is executed before the start of the first dewatering process which is performed after the washing process. If the amount of foam detected by the foam amount detection unit is equal to or greater than a predetermined value, the second defoaming step is executed after the completion of the first defoaming step and before the start of the first dewatering step. washing machine.
2. In the first defoaming step, no water is supplied by the water supply valve control unit. The second defoaming step is executed when the amount of foam in the first defoaming step is equal to or greater than a predetermined value. The washing machine according to claim 1.
3. In the second defoaming step, water is supplied to the tank until it is submerged in the clothes, and then left for a predetermined time. The washing machine according to claim 2.
4. If the amount of foam in the first defoaming step is less than a predetermined value, only the first defoaming step is performed. The washing machine according to claim 3.
5. The foam volume detection unit is a water level sensor, The amount of detergent foam is detected based on the water level in the tank. A washing machine according to any one of claims 1 to 4.