JP5383435B2 - Washing machine - Google Patents

Description

  The present invention relates to a washing machine that is connected to a storage tub that stores laundry and detects an abnormality in a flow path through which air in the storage tub flows.

  As a washing machine, there is a so-called drum-type washing machine in which a rotating drum for storing laundry is disposed obliquely in a water tub, and washing, rinsing, dewatering, and drying are performed in the inclined rotating drum. In order to save water, this washing machine has a circulation path for once draining the water supplied to the water tank, filtering it with a filter or the like, and then supplying water again into the water tank. If there is a large amount of detergent used during washing, the generated foam may enter the circulation path. In such a case, the washing machine may break down due to the intruded foam. Then, the washing machine which can detect the water level in a water tank and the height of foam is proposed (for example, patent documents 1). The washing machine described in Patent Document 1 is provided with two electrodes on the top and bottom in a water tank. When the two electrodes increase in water or bubbles in the water tank and are immersed in water or bubbles, the capacitance between the electrodes changes as water or bubbles becomes a conductive material. So, in patent document 1, the electrostatic capacitance between the electrodes which change is detected and the water level in a water tank and the height of a bubble are detected.

JP 7-185183 A

  However, when the electrodes are immersed in water or bubbles, an electric current flows between the electrodes. In this case, there is a possibility that the electrodes are electrolytically corroded (corroded) by electrolysis. As a result, it is impossible to accurately detect the capacitance between the electrodes, and as a result, there arises a problem that the water level and the height of the bubbles cannot be normally detected.

  This invention is made | formed in view of this situation, The place made into the objective is to provide the washing machine which can perform normal foam detection, without carrying out the electrolytic corrosion of an electrode.

Washing machine according to the present invention, the laundry communicates the air flow passage in the container for accommodating a, that to prevent foaming of the housing tank from entering a predetermined position downstream of the air flow passage Washing In the machine, the first and second electrodes, which are spaced apart from the predetermined positions in the air flow passage and to which DC voltages having opposite polarities are applied, and the current flowing between the first and second electrodes , A determination means for determining whether or not a bubble has entered; and an inversion means for periodically reversing the polarity of a DC voltage applied to the first and second electrodes , wherein the determination means prevents the bubble from entering. when it is determined it has a structure to said tare Rukoto to discharge bubbles of the air flow passage.

  In the present invention, the first and second electrodes are provided separately in the air flow passage communicated with the storage tank, and a DC voltage having a reverse polarity is applied to each of the first and second electrodes. If there is no abnormality in the flow path, current does not flow between the first and second electrodes that are separated from each other. For example, when bubbles generated in the storage tank during washing enter the air flow passage The first and second electrodes are short-circuited with bubbles, and a current flows between the first and second electrodes. For this reason, by detecting that an electric current has flowed between the first and second electrodes, it is possible to detect that there is an abnormality in the air flow passage and to avoid a failure of the washing machine, or to grasp the cause of the failure. it can. In the present invention, the polarity of the DC voltage applied to the first and second electrodes can be reversed. Thereby, it is possible to avoid the possibility that the electrode is corroded by electrolysis because the current always flows in the same direction.

  In the washing machine according to the present invention, the inversion means applies a first switch for turning on / off application of a positive direct current voltage to the first electrode and an application of a positive direct current voltage to the second electrode. A second switch to be turned on / off; a means for alternately turning on the first and second switches; and application of a negative DC voltage to the second electrode in accordance with the on / off of the first switch. A third switch for turning on / off the second switch and a fourth switch for turning on / off the application of a negative DC voltage to the first electrode in response to the turning on / off of the second switch. Features.

  In the present invention, the direction of the current flowing between the first and second electrodes can be reversed by switching on / off of each switch. Thereby, it is possible to avoid the possibility that the electrode is corroded by electrolysis because the current always flows in the same direction.

  The washing machine according to the present invention is characterized in that the first, second, third and fourth switches are transistors.

  In the present invention, by using transistors, an increase in cost can be prevented.

Washing machine according to the present invention, the switching means turns off one of the first and second switches, and wherein the you have to so that after a time delay the other hand until it ounces.

  In the present invention, it is possible to prevent the first and second switches from being turned on simultaneously by providing a predetermined time between the on and off control of the first and second switches.

  In the washing machine according to the present invention, the determination unit has a detection unit that repeatedly detects a current flowing between the first and second electrodes, and when the first or second switch is on, When the detection means detects a current a predetermined number of times, it is determined that a current has flowed.

  In the present invention, it can be determined that the current has flowed when the current detection is performed a predetermined number of times, so that even if the current flows temporarily due to noise or the like, it can be determined that the current has not flown, so that erroneous detection is avoided. it can.

  In the washing machine according to the present invention, each time the first and second switches are turned on, the determination unit determines whether or not a current flows, and the determination unit continuously flows a current. And a means for invalidating the determination result by the determination means when the number of times determined to be equal to or less than a predetermined value.

  In the present invention, when it is not determined that the current has flowed continuously for a predetermined number of times, it is determined that the current has flowed even if the current flows temporarily due to noise or the like by not determining that the current has flowed. Since this can be avoided, false detection can be avoided.

The washing machine according to the present invention is characterized in that the detection means starts detection of a current after a predetermined time from the time when the first or second switch is turned on.

  Immediately after the switching of the first or second switch, chattering (a phenomenon in which electrical signals repeat intermittently) occurs. For this reason, in the present invention, the influence of chattering can be avoided by performing current detection after a predetermined time has elapsed since the first or second switch was turned on.

  In the present invention, for example, when foam generated in the storage tub during washing enters the air flow passage, an abnormality is detected in the air flow passage by detecting that a current flows between the first and second electrodes. It is possible to detect a certain situation and to avoid a failure of the washing machine or to understand the cause of the failure. Further, by reversing the polarity of the DC voltage applied to the first and second electrodes, it is possible to avoid the possibility that the electrodes corrode due to electrolysis.

It is a perspective view which shows roughly the external appearance of the whole washing-drying machine which concerns on embodiment. It is sectional drawing of the washing-drying machine in the II-II line shown in FIG. It is the figure which looked at the inside of the exterior of the washing-drying machine shown in FIG. 1 from the front. It is the figure which looked at the inside of the exterior of the washing / drying machine shown in FIG. 1 from the back. It is a control block diagram of the washing / drying machine concerning an embodiment. It is a figure which shows the equivalent circuit of a bubble detection circuit. It is a figure which shows the timing which a control part detects the on-off timing of a positive electrode and a negative electrode switch, and the output electric potential from a bubble detection circuit. It is a flowchart which shows a bubble detection process. It is a flowchart which shows a bubble detection process. It is a flowchart which shows a bubble detection process.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of a washing machine according to the invention will be described with reference to the drawings.

  FIG. 1 is a perspective view schematically showing the overall appearance of the washing / drying machine according to the present embodiment. 2 is a cross-sectional view of the washing / drying machine taken along line II-II shown in FIG. FIG. 3 is a view of the inside of the exterior of the washing / drying machine shown in FIG. 1 as viewed from the front. 4 is a view of the inside of the exterior of the washing and drying machine shown in FIG. 1 as viewed from the back.

  The washing / drying machine 1 according to the present embodiment includes an exterior 10. The exterior 10 has a front surface that curves forward and a circular insertion port (not shown) is formed above the approximate center of the front surface so as to open obliquely upward. The outer door 11 is rotatably attached to the insertion port by a hinge (not shown). An inner door 12 is attached to the inner side of the outer door 11. The inner door 12 is attached so as to open and close in conjunction with the opening and closing of the outer door 11. Specifically, the inner door 12 is also opened by opening the outer door 11, and the inner door 12 is also closed by closing the outer door 11.

  In the exterior 10, a bottomed cylindrical water tank 2 for storing washing water is disposed. The front surface of the water tank 2 is open, and the water tank 2 is disposed sideways so that the opening faces the charging port of the exterior 10. More specifically, the water tank 2 is inclined so that the central axis forms an angle of 5 ° to 30 ° with respect to the horizontal direction, the upper part is a support spring (not shown), and the lower part is the support dampers 13 and 13. Etc. are elastically supported. A packing (not shown) made of an elastic material such as rubber or soft resin is fixed to the opening of the water tank 2, and when the inner door 12 is closed, the inner door 12 is in close contact with the packing, The liquid is prevented from leaking outside.

  Washing water is supplied to the water tank 2 from a water supply duct 19 shown in FIG. The water tank 2 is provided with a drain outlet for draining the washing water, and an internal drain hose 14 is connected to the drain outlet. The internal drain hose 14 is connected to an external drain hose 16 via a drain valve 15 provided at the bottom of the water tank 2. The drain valve 15 is opened and closed by a drain motor (not shown). By opening and closing the drain valve 15, washing water containing detergent in the water tank 2 is drained through the internal drain hose 14 and the external drain hose 16. A circulation pump 17 is provided at the bottom of the water tank 2, and the circulation pump 17 supplies water flowing from the internal drain hose 14 into the water tank 2 again via the circulation hose 18.

  In the water tank 2, a bottomed cylindrical rotary drum (storage tank) 3 for storing the laundry 30 is rotatably arranged. The rotating drum 3 is disposed so that the opening portion faces the opening portion of the water tank 2 and the central axis is parallel to the central axis of the water tank 2. Therefore, the central axis of the rotating drum 3 is inclined so as to form an angle of 5 ° to 30 ° with respect to the horizontal direction.

  A plurality of small holes 31 are provided in the entire peripheral wall of the rotating drum 3. The small hole 31 is for circulating wash water or dry air between the space between the water tank 2 and the rotary drum 3 and the space in the rotary drum 3. A baffle 32 is provided on the inner wall surface of the rotating drum 3 so as to protrude inward in the radial direction. The baffle 32 is configured so as to perform a tapping action of lifting the laundry 30 upward and dropping it from above as the rotary drum 3 rotates. Further, a fluid balancer 33 is fixed to the periphery of the opening of the rotary drum 3 to prevent vibration during rotation.

  The rotary drum 3 is rotatably supported by the shaft portion 4a. The shaft portion 4 a is connected to the drum motor 4 at the rear end, and transmits a rotational driving force to the rotary drum 3. The rotation of the drum motor 4 is controlled by a control unit 20 disposed at the lower part in the washing / drying machine 1.

  A steam generator 7 that generates steam is disposed above the water tank 2. The steam generator 7 is connected to a steam injection port 8 disposed at the upper part of the opening of the water tank 2 through a heat-resistant silicon hose 7a. The steam generated in the steam generator 7, that is, steam, is jetted into the rotary drum 3 from the steam jet port 8 at about 100 ° C. through the silicon hose 7a during the washing process or the drying process. By ejecting steam into the rotating drum 3, the temperature of the laundry 30 in the rotating drum 3 can be raised. As a result, the detergency can be increased during the washing step, the wrinkles fixed to the laundry 30 can be removed during the drying step, and the softness, that is, the elasticity of the clothing can be maintained, and the touch or texture can be dried well.

  A cooling duct 6 is connected to the back side of the water tank 2. As shown in FIG. 4, the cooling duct 6 extends in the vertical direction on the back side of the water tank 2, and is connected to an exhaust duct 9 disposed in the upper part of the water tank 2. The exhaust duct 9 is provided with a drying fan for blowing air for sending air, a fan motor for rotating the drying fan, and a filter for removing yarn waste mixed with the blowing, which are not shown. When the drying fan rotates, the air in the water tank 2 flows into the cooling duct 6. In the cooling duct 6, air supplied into the cooling duct 6 is cooled and dehumidified by water supplied from a cooling water supply hose (not shown), and flows upward in the cooling duct 6 to flow into the exhaust duct 9. Flows in.

  Electrodes 61 and 62 are attached to the cooling duct 6, and the electrode 61 is provided at a position above the electrode 62. In the cooling duct 6, for example, bubbles generated in the water tank 2 may invade in the washing process. When the bubbles enter the position where the electrodes 61 and 62 are immersed, the electrodes 61 and 62 are short-circuited by the bubbles. When the electrodes 61 and 62 are short-circuited by bubbles, a current flows between the electrodes 61 and 62. Therefore, it can be detected that bubbles have entered the cooling duct 6 by detecting that a current flows between the electrodes 61 and 62. In addition, when a bubble is detected, the process which discharges the bubble in the cooling duct 6 is performed.

  In the present embodiment, the electrodes 61 and 62 are provided at a position where bubbles that have entered the position that may cause a problem in the device can be detected. Since the drying fan or the like is provided on the path of the cooling duct 6 as described above, when the bubbles fill the cooling duct 6, these devices may break down due to the bubbles. For this reason, failure of the washing / drying machine 1 can be prevented by providing the electrodes 61 and 62 at positions where the bubbles can be monitored so as not to exceed the danger zone.

  Further, when a current flows between the short-circuited electrodes 61 and 62, the direction of the current is reversed at a constant cycle (for example, 1 second cycle). In other words, the polarities of the electrodes 61 and 62 are alternately switched. When a current always flows in the same direction, the electrodes 61 and 62 become eroded (corroded) by electrolysis. For this reason, electrolytic corrosion of the electrodes 61 and 62 can be prevented by periodically reversing the direction in which the current flows.

  Although the exhaust duct 9 is interrupted in FIG. 2, the exhaust duct 9 extends toward the front side. The exhaust duct 9 is connected to an air supply duct 91 (see FIG. 3) provided on the front side of the exterior 10. The air supply duct 91 is provided with a PTC (Positive Temperature Coefficient) heater 92 for heating the air in the air supply duct 91. Above the water tank 2, a hot air outlet 93 that blows out hot air is disposed, and the air heated by the air supply duct 91 is blown out from the hot air outlet 93 toward the inside of the water tank 2.

  A water temperature thermistor (not shown) is disposed at the lowermost part of the cooling duct 6. In the exhaust duct 9, an exhaust thermistor (not shown) is disposed on the upstream side of the drying air flow of the drying fan. The water temperature thermistor and the exhaust thermistor are connected to the control unit 20, and each of the water temperature thermistor and the exhaust thermistor detects the temperature and transmits the detected temperature to the control unit 20.

  An operation circuit 40 is disposed above the water tank 2. A control unit 20 is disposed below the water tank 2. The operation circuit 40 receives a signal from the operation panel 10 a when the user operates the operation panel 10 a disposed on the outer peripheral surface of the exterior 10 in order to operate the washing / drying machine 1. A control signal is transmitted to the control unit 20 arranged in the. The control unit 20 transmits a control signal to each member of the washing / drying machine 1 such as the drum motor 4, the drain valve 15, the circulation pump 17, etc., and controls the operation of each member.

  FIG. 5 is a control block diagram of the washing / drying machine 1 according to the present embodiment.

  The control unit 20 serving as the center of the control operation provided in the washing / drying machine 1 includes a CPU (Central Processing Unit) 21, a memory 22, a timer 23, an I / O 24, and the like. The CPU 21 outputs necessary control instructions to peripheral devices described later in the washing / drying machine 1. The memory 22 stores information necessary for executing the calculation of the CPU 21 and stores a control program and the like necessary for instructing the control instruction for controlling each peripheral device from the CPU 21. The timer 23 outputs necessary time information according to an instruction from the CPU 21. The I / O 24 enables data communication between the control unit 20 and the peripheral device.

  As peripheral devices, a drum motor 4, a steam generator 7, a drain valve 15, a circulation pump 17, an operation circuit 40, a water supply valve 41, a pump motor 42, a fan motor 43, a water temperature thermistor 44, an exhaust thermistor 45, a PTC heater 92, and the like A foam detection circuit 63 and the like are provided in the washing / drying machine 1. The water supply valve 41 supplies water to the water tank 2 through the water supply duct 19 by opening. The pump motor 42 drives a steam pump that sends water to the steam generator 7. The fan motor 43 is a motor that rotates the drying fan of the exhaust duct 9.

  The bubble detection circuit 63 is a circuit for detecting that bubbles have entered the position where the electrodes 61 and 62 in the cooling duct 6 are provided. Based on the output potential of the bubble detection circuit 63, the control unit 20 determines whether or not bubbles have penetrated to the position of the electrode 61 in the cooling duct 6. The bubble detection circuit 63 is also a circuit for periodically reversing the direction of current flow when current flows between the electrodes 61 and 62 in order to prevent electrolytic corrosion of the electrodes 61 and 62 due to electrolysis.

  Hereinafter, the configuration of the bubble detection circuit 63 will be described in detail. FIG. 6 is a diagram showing an equivalent circuit of the bubble detection circuit 63. The bubble detection circuit 63 includes npn transistors 71, 72, 73, 74, 75, 76, and the like. The transistors 71, 73, and 74 and the transistors 72, 75, and 76 are mirror-arranged. Hereinafter, the connection configuration of the transistors 71, 73, and 74 will be described, and the transistors 72, 75, and 76 are shown in parentheses. explain.

  The transistor 71 (72) has a collector connected to a 5 V power source via an ammeter 77, a base connected to the control unit 20, and is turned on / off by the control unit 20. The emitter of the transistor 71 (72) is connected to the collector of the transistor 73 (75), the base of the transistor 75 (73), the collector of the transistor 76 (74), and the electrode 61 (62). The emitter of the transistor 73 (75) is connected to the base of the transistor 74 (76) that is emitter-connected.

  In the bubble detection circuit 63 configured as described above, the transistors 71 and 72 are alternately turned on by the control unit 20. When the transistor 71 (72) is turned on, a current flows from the transistor 71 (72) to the base of the transistor 75 (73), and the transistor 75 (73) is turned on. When the transistor 75 (73) is turned on, the current flowing through the transistor 74 flows to the collector of the transistor 75 (73) through the electrode 61 (62) and the electrode 62 (61) short-circuited by bubbles or the like. Since the transistor 75 (73) is on, the current that flows to the collector of the transistor 75 (73) flows to the base of the transistor 76 (74), and the transistor 76 (74) is turned on. Current will flow. Thus, by detecting the current value of the ammeter 77 by the control unit 20, it is possible to determine whether or not the electrodes 61 and 62 are short-circuited and a current flows between the electrodes 61 and 62. By reversing the polarity of 62, electrolytic corrosion of the electrodes 61 and 62 due to electrolysis can be prevented.

  Next, a washing process, a rinsing process, a dehydrating process, and a drying process performed using the laundry dryer 1 will be described in the order of the processes.

  First, the user opens the outer door 11 and the inner door 12, puts the laundry 30 into the rotating drum 3, and then closes the inner door 12 and the outer door 11. The user puts the detergent in the detergent case and, if necessary, the finishing agent in a finishing agent case (not shown). You may put a finishing agent in the middle of a washing process or a rinse process.

  Next, when the user operates the operation panel 10a, the control unit 20 controls each member of the washing / drying machine 1 according to the conditions, and performs the washing process, the rinsing process, the dehydrating process, and the drying process continuously or independently. . Here, the case where all the processes of a washing process, a rinse process, a dehydration process, and a drying process are performed is demonstrated.

  When the user presses the start button on the operation panel 10a, the outer door 11 and the inner door 12 are locked, and the drain valve 15 is closed. And the water supply valve 41 is opened, and tap water is supplied in the water tank 2 from the water supply duct 19 through a detergent case. In this way, the washing process is started. When a water level sensor (not shown) detects that the water level in the water tank 2 has reached a predetermined value, the water supply valve 41 is closed and then the circulation pump 17 is driven. The rotating drum 3 is rotated by the drum motor 4 in accordance with the rotation chart for the washing process, and the steam generator 7 is driven.

  The water supplied into the water tank 2 is supplied into the rotary drum 3 by the circulation pump 17 through the internal drain hose 14 and the circulation hose 18. The water supplied into the rotary drum 3 flows out into the water tank 2 through the small hole 31 and is circulated again by the circulation pump 17. The circulation pump 17 is driven for a predetermined time and stops when the predetermined time elapses.

  When the drum motor 4 rotates forward and backward, the rotating drum 3 also rotates forward and backward in the same manner. When the rotating drum 3 rotates, the baffle 32 fixed to the inner peripheral wall surface of the rotating drum 3 lifts the laundry 30 and drops it downward. In this way, the washing step is performed using a so-called tapping effect. In addition, steam is generated by the steam generator 7, the steam is injected into the rotary drum 3 from the steam injection port 8, and the laundry 30 is heated by the steam, thereby improving the cleaning power.

  In the washing process, a bubble detection process described later is performed, and when bubbles enter the position of the electrode 61 in the cooling duct 6, the bubbles are detected. When bubbles are detected, the drain valve 15 is opened, and the rinsing liquid in the water tank 2 is drained from the external drain hose 16 outside the exterior 10. When bubbles are detected, if the water supply valve 41 is open, the water supply valve 41 is closed and water supply into the water tank 2 is stopped.

  When the washing process is completed, the drain valve 15 is opened, and water is drained from the external drain hose 16 to the outside of the exterior 10. When the drainage is completed, an intermediate dehydration process is performed in which the rotary drum 3 is rotated at a high speed by a rotation chart for the intermediate dehydration process. In the intermediate dehydration step, the water contained in the laundry 30 is discharged to the inner wall surface of the water tub 2 through the small holes 31 provided in the peripheral wall of the rotating drum 3 by centrifugal force due to the high-speed rotation of the rotating drum 3. The water flows down along the inner wall surface of the water tank 2 and is drained from the external drain hose 16 to the outside of the exterior 10 through the drain valve 15.

  When the intermediate dehydration process is completed, the process proceeds to the rinsing process. After the drain valve 15 is closed, the water supply valve 41 is opened and tap water is supplied to the water tank 2. When it is detected by a water level sensor (not shown) that the water level in the water tank 2 has reached a predetermined value, the water supply valve 41 is closed. After the water supply valve 41 is closed, the circulation pump 17 is driven for a predetermined time, and the rotary drum 3 is rotated by the drum motor 4 in accordance with the rotation chart for the rinsing process. When the rinsing process is completed, the drain valve 15 is opened, and water is drained from the external drain hose 16 to the outside of the exterior 10. When drainage is completed, the process proceeds to an intermediate dehydration process.

  After the intermediate dehydration step and the rinsing step are repeated a plurality of times, the process proceeds to the final rinsing step. In the final rinsing step, the water supply valve 41 is opened, and the soft finish in the detergent case is supplied from the water supply duct 19 to the water tank 2 as water containing the soft finish.

  When the final rinsing step is completed, the drain valve 15 is opened and the rinse liquid is drained from the external drain hose 16 to the outside of the exterior 10. When the drainage is completed, the rotary drum 3 is rotated at a high speed according to the rotation chart for the final dehydration process, and the final dehydration process is performed. In the final dehydration step, the rinsing liquid contained in the laundry 30 by centrifugal force due to the high-speed rotation of the rotating drum 3 is passed through the small holes 31 provided in the peripheral wall of the rotating drum 3 in the same manner as in the intermediate dehydrating step. And discharged to the outside of the exterior 10.

  When the final dehydration process is completed, the process proceeds to the drying process. In the drying process, the rotary drum 3 is rotated and the PTC heater 92 and the fan motor 43 are driven. In the case where the washing and drying processes are continuously performed, the PTC heater 92 may be driven from the final dehydration process. By doing in this way, the temperature in the rotating drum 3 rises, it dehydrates better, and it becomes possible to implement drying efficiently.

  By driving the PTC heater 92 and the fan motor 43, the air heated by the PTC heater 92 is blown into the water tank 2 and the rotating drum 3 from the hot air outlet 93. The heated air heats the laundry 30 in the rotating drum 3, then flows out through the small hole 31 to the water tank 2, and is exhausted from the lower part of the water tank 2 to the cooling duct 6. The gas exhausted to the cooling duct 6 has a high humidity due to moisture contained in the laundry 30 in the rotating drum 3. The air containing moisture is cooled by the cooling duct 6 and dehumidified. The moisture removed from the gas returns to the water tank 2 from below the cooling duct 6, and is drained from the exterior 10 through the internal drain hose 14, the drain valve 15, and the external drain hose 16. The air dehumidified by the cooling duct 6 returns to the air supply duct 91 through the exhaust duct 9. The air supply duct 91 is heated by the PTC heater 92. A drying process is performed by repeating these cycles.

  Next, the bubble detection process performed at a washing process is demonstrated. In the following description, when current flows between the electrodes 61 and 62, the transistor 71 that makes the electrode 61 a positive electrode is called a positive switch 71, and the transistor 72 that makes the electrode 61 a negative electrode is called a negative switch 72.

  FIG. 7 is a diagram illustrating the timing at which the control unit 20 turns on and off the positive and negative electrodes and the timing at which the output potential from the bubble detection circuit 63 is detected.

  The control unit 20 (specifically, the CPU 21) turns on the positive electrode switch 71 for a time T1 (0.9 seconds). Thereafter, the control unit 20 turns on the negative electrode switch 72 for a time T1 with an interval of time T2 (0.1 seconds). As described above, the control unit 20 repeats the process of alternately turning on and off the positive electrode switch 71 and the negative electrode switch 72 at intervals of 1 second. By providing the time T2 between when the positive switch 71 is turned off and when the negative switch 72 is turned on, the positive switch 71 and the negative switch 72 are prevented from being turned on simultaneously.

  The control unit 20 detects the output potential of the bubble detection circuit 63 from the result of current measurement by the ammeter 77 after the time T3 (0.4 seconds) has elapsed since the positive switch 71 or the negative switch 72 was turned on. Immediately after switching between the positive electrode switch 71 and the negative electrode switch 72, chattering (a phenomenon in which an electric signal repeats intermittent) occurs. Therefore, the influence of chattering can be avoided by detecting the output potential after the time T3 has elapsed since turning on. it can.

  The control unit 20 repeatedly detects the output potential of the bubble detection circuit 63 for a time T4 (0.05 seconds). For example, the control unit 20 detects the output potential three times at intervals of 10 μs, and adopts the output potential detected with a large amount of Hi or Lo. The control unit 20 repeats such processing 50 times every 1 ms, that is, for a time T4 (0.05 seconds). As a result of repetition, when the output potential of Lo is adopted 26 times, the control unit 20 detects that the bubble has penetrated to the position of the electrode 61 in the cooling duct 6.

  Next, specific processing contents of the bubble detection processing will be described. 8, 9 and 10 are flowcharts showing the bubble detection process. 8, 9, and 10 are executed by the CPU 21 of the control unit 20.

  CPU21 performs the process which confirms whether there is any abnormality in the bubble detection circuit 63 (S1), and determines whether the bubble detection circuit 63 is abnormal (S2). Specifically, the CPU 21 turns off both the positive switch 71 and the negative switch 72. In this case, since no current flows in the bubble detection circuit 63, the output potential of the bubble detection circuit 63 is Hi. Therefore, the CPU 21 determines that the bubble detection circuit 63 is abnormal when detecting the output potential of Lo for a certain time (for example, 300 ms). When it is determined that the circuit is abnormal (S2: YES), the CPU 21 forcibly ends this process. At this time, CPU21 may alert | report abnormality and may continue a washing process, and may complete | finish a washing process.

  When it is determined that there is no circuit abnormality (S2: NO), the CPU 21 turns on the positive switch 71 (S3) and waits for a time T3 (S4). The CPU 21 performs output potential determination processing (S5). In the output potential determination process, as described above, the CPU 21 detects the output potential of the bubble detection circuit 63 three times at intervals of 10 μs, and adopts the output potential detected with a large amount of Hi or Lo. For example, when the output potential of Lo is detected twice and the output potential of Hi is detected once, the CPU 21 determines that the output potential is Lo. The CPU 21 makes such a determination every 1 ms.

  The CPU 21 determines whether or not the time T4 has elapsed since the start of the output potential determination process (S6). When the time T4 has not elapsed (S6: NO), the CPU 21 repeats the process of S5. That is, the CPU 21 repeats the determination process performed every 1 ms 50 times for a time T4 (0.05 seconds). When the time T4 has elapsed (S6: YES), the CPU 21 determines whether or not bubbles have been detected as a result of performing the output potential determination process (S7). For example, as a result of determining the output potential 50 times every 1 ms, when the number of times that the output potential is determined to be Lo is 26 times or more, the CPU 21 detects bubbles, and when it is less than 26 times, The CPU 21 does not detect bubbles. As described above, by detecting the output potential a plurality of times and adopting the result of more detection, erroneous detection due to noise or the like can be avoided.

  When the bubble is detected (S7: YES), the CPU 21 adds “1” to the number of continuous detections (S8). The number of times of continuous detection is the number of times bubbles are continuously detected when the positive electrode switch 71 and the negative electrode switch 72 are alternately turned on, and the initial value is “0”. When the bubble is not detected (S7: NO), the CPU 21 resets the number of times of continuous detection (S9). Thereafter, the CPU 21 determines whether or not the time T1 has elapsed since the positive switch 71 was turned on (S10). When the time T1 has not elapsed (S10: NO), the CPU 21 waits until it elapses. When the time T1 has elapsed (S10: YES), the CPU 21 turns off the positive switch 71 (S11).

  Next, the CPU 21 waits for a time T2 (S12), and turns on the negative electrode switch 72 (S13). The CPU 21 waits for a time T3 (S14), performs an output potential determination process similar to S5 (S15), It is determined whether or not the time T4 has passed (S16). When the time T4 has not elapsed (S16: NO), the CPU 21 repeats the process of S15. When the time T4 has elapsed (S16: YES), the CPU 21 determines whether or not bubbles have been detected as a result of performing the output potential determination process (S17). When the bubble is detected (S17: YES), the CPU 21 adds “1” to the number of continuous detections (S18). When the bubble is not detected (S17: NO), the CPU 21 resets the number of times of continuous detection (S19). Thereafter, the CPU 21 determines whether or not the time T1 has elapsed since the positive switch 71 was turned on (S20). When the time T1 has not elapsed (S20: NO), the CPU 21 waits until it elapses. When the time T1 has elapsed (S20: YES), the CPU 21 turns off the negative switch 71 (S21).

  The CPU 21 waits for a time T2 (S22), and determines whether or not the number of continuous determinations has reached a predetermined value (for example, 6 times) (S23). When the number of continuous determinations is not a predetermined value (S23: NO), the CPU 21 executes the process of S3. When the number of continuous determinations is a predetermined value (S23: YES), the CPU 21 executes a bubble discharge process (S24). In the foam discharge process, the CPU 21 opens the drain valve 15 and drains the rinsing liquid in the water tank 2 from the external drain hose 16 outside the exterior 10. If the water supply valve 41 is open, the CPU 21 closes the water supply valve 41 and stops water supply into the water tank 2. When bubbles are detected continuously a predetermined number of times, by performing the bubble discharge process, erroneous detection due to noise or the like can be avoided, or detection of bubbles that have entered temporarily can be avoided.

  CPU21 determines whether a process is complete | finished (S25). The case of terminating the process is, for example, a case where the power of the washing / drying machine 1 is turned off. When the process is not terminated (S25: NO), the CPU 21 returns the process to S3. When the process is to be ended (S25: YES), the CPU 21 ends the process.

  As described above, the drying washing machine 1 according to the present embodiment includes the electrodes 61 and 62 in the cooling duct 6, and detects that a current flows between the electrodes 61 and 62. Detecting the invasion of bubbles. Thereby, failure of the equipment of the washing and drying machine 1 due to foam can be avoided. Further, by periodically reversing the direction of the current flowing between the electrodes 61 and 62, corrosion of the electrodes 61 and 62 necessary for bubble detection can be prevented, and normal bubble detection can always be performed.

  The preferred embodiment of the present invention has been specifically described above, but each configuration, operation, and the like can be changed as appropriate, and are not limited to the above-described embodiment. For example, the transistors 71 and 72 are used to invert the polarities of the electrodes 61 and 62, but a three-contact switch may be used, and the circuit configuration of the bubble detection circuit 63 can be changed as appropriate. Further, specific numerical values such as the period for reversing the polarities of the electrodes 61 and 62 and the above-described times T1, T2, T3, and T4 are not limited to the above-described embodiment. Furthermore, in the present embodiment, the washing / drying machine has been described as an example, but may not have a drying function.

1 Washing dryer 2 Water tank (container)
6 Cooling duct (air flow passage)
20 Control unit (determination means, switching means, detection means)
61, 62 Electrode 63 Bubble detection circuit (reversing means)
71, 72 transistors (first and second switches)
73, 74 Transistor (4th switch)
75,76 transistor (third switch)

Claims (7)

Laundry and air flow passage in communication with the accommodating tank for accommodating the at washing machine that to prevent foaming of the housing tank from entering a predetermined position downstream of the air flow passage,
A first electrode and a second electrode which are provided apart from each other at the predetermined position in the air flow path and to which DC voltages having opposite polarities are applied;
Determination means for determining Taka whether bubbles invade based on current flowing between the first and second electrodes,
Reversing means for periodically reversing the polarity of the DC voltage applied to the first and second electrodes, and when the determination means determines the intrusion of bubbles, the bubbles in the air flow passage are discharged. configuration and a washing machine which is characterized tare Rukoto to. The inversion means is
A first switch for turning on / off application of a positive DC voltage to the first electrode;
A second switch for turning on / off application of a positive DC voltage to the second electrode;
Switching means for alternately turning on the first and second switches;
A third switch that turns on / off application of a negative DC voltage to the second electrode in response to on / off of the first switch;
The laundry according to claim 1, further comprising: a fourth switch that turns on / off application of a negative DC voltage to the first electrode in accordance with on / off of the second switch. Machine. The washing machine according to claim 2, wherein the first, second, third, and fourth switches are transistors. The switching means is
Washing machine according to claim 2 or 3, characterized in that to turn off one of the first and second switches, are the so that after a time delay the other hand until it ounces. The determination means includes
Detecting means for repeatedly detecting a current flowing between the first and second electrodes;
5. The device according to claim 2, wherein when the first or second switch is on, it is determined that the current flows when the detection unit detects the current a predetermined number of times. The washing machine according to one. The determination means includes
Each time the first and second switches are switched on, it is determined whether or not current has flowed,
The washing machine according to claim 5, further comprising: means for invalidating a determination result by the determination means when the number of times that the determination means determines that current has continuously flowed is equal to or less than a predetermined value. The detection means includes
The washing machine according to claim 5 or 6, wherein detection of current is started after a predetermined time from the time when the first or second switch is turned on.

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