JP2008099981A - Washing/drying machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water level sensor capable of securely sensing a water level in a water storage part of condensate generated at drying clothes with an inexpensive constitution. <P>SOLUTION: The washing/drying machine is provided with: a washing tub 3 for housing the fabrics, objects to be washed and dried, to wash/dry them; a dehumidifier 6 for dehumidifying humid air; a blowing device 12 for sending the humid air inside the tub 3 to the dehumidifier 6 when drying the fabrics; the water storage part 23 for storing the condensate generated in the dehumidifier 6; a drainage device 24 for draining water from the storage part 23; and the water level sensor for sensing the water level inside the storage part 23. At least either one of operations of the dehumidifier 6 and the drainage device 24 is controlled according to an output sensed by the sensor. The sensor is provided with a pair of water level sensing electrodes 40a and 40b disposed inside the storage part 23 and an oscillation circuit 43 having a pair of the electrodes 40a and 40b inserted in a feedback circuit, sensing the presence/absence of water between the electrodes 40a and 40b from a change in oscillation frequencies of the circuit 43 through a change of a feedback current according to an electric resistance between the electrodes 40a and 40b. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a washing / drying machine having a function of drying laundry along with a washing and dehydrating function.

  Conventionally, in the drying process of the clothes after the washing process of this type of washing and drying machine, drying air containing water vapor from the clothes is applied to the evaporator to dehumidify the air, and the air is heated through the condenser. As a result, it is circulated through a rotating drum for drying.

  FIG. 7 is a schematic cross-sectional view of the washing / drying machine described in Patent Document 1. In this washing / drying machine, a rotating drum 2 that houses clothing 1 is rotatably supported in a washing tub 3. A rotating shaft 4 of the rotating drum 2 is connected to a motor 5. Below the washing tub 3 is provided a dehumidifying device 6 which has a heat pump cycle and performs the action of removing moisture by introducing moist air from the washing tub 3 during drying.

  The heat pump cycle includes a compressor 7, an evaporator 8 that absorbs heat, a condenser 9 that generates heat, and a capillary tube 10. The air between the evaporator 8, the condenser 9 and the washing tub 3 is circulated and moved by the blower 12 via the air passage 11. The evaporator 8 acts to suck heat from the air into the refrigerant by evaporating the refrigerant passing through the inside. On the other hand, the condenser 9 acts to apply heat from the refrigerant to the air.

  A first drive circuit 13 is connected to the motor 5, and a second drive circuit 14 is connected to the compressor 7. The first drive circuit 13 is supplied with a DC voltage of about 250 V by the voltage doubler first rectifier circuit 15, and the second drive circuit 14 is 230 V by the voltage doubler second rectifier circuit 16. DC voltage is supplied. The power plug 17 that supplies AC power to the first rectifier circuit 15 and the second rectifier circuit 16 is configured to suppress power harmonics and terminal noise.

  The water supply unit 18 is composed of a water pipe 19 and a water supply valve 20 that opens and closes water from the water pipe 19 by opening and closing. Water is supplied from the water supply unit 18 to the washing tub 3, and clothing is stored in the washing tub 3. 1 is also configured to perform washing and dehydration. The drain valve 21 is provided in the lower part of the washing tub 3. When the drain valve 21 is closed, water is stored in the washing tub 3 for washing and rinsing. When the drain valve 21 is opened, the water in the washing tub 3 is stored. Is discharged to the drain pipe 22.

  When clothes are dried, the humid air in the washing tub 3 is sent to the evaporator 8 which is at a low temperature, where it is cooled to generate condensed water, which is stored at the bottom of the dehumidifier 6. 23 drops and accumulates. A drainage pump 24 is provided to drain the condensed water accumulated in the water storage unit 23. The drainage pump 24 has a structure called a gear pump, and is fitted to the first electric gear 26 rotated by the electric motor 25, the first gear 26 rotated by the electric motor 25, and the first gear 26. A second gear 27 that rotates in the opposite direction to the gear 26 and a case 28 that surrounds the first gear 26 and the second gear 27 are provided, and a filter 29 is provided on the entrance side. Condensed water is sucked up from the water storage unit 23 by the drainage pump 24 and is poured out into the overflow tray 30. The condensed water discharged to the overflow tray 30 is joined again to the drain pipe 22 via the overflow pipe 31.

  The water storage unit 23 is provided with a water level sensor 32 that detects the level of accumulated condensed water. The water level sensor 32 has a thermistor 33 having self-heating characteristics. When the signal from the thermistor 33 is within a predetermined range, the operation of the dehumidifier 6 is controlled to stop. Therefore, since the water level of the condensed water does not rise after that, secondary failure or malfunction due to water on the components inside the washer / dryer due to excessive rise of the water level, and further to the outside of the washer / dryer Can be surely prevented from overflowing.

  Further, instead of stopping the compressor 7 by a signal from the water level sensor 32, for example, the drainage pump 24 is driven while continuing the operation of the dehumidifying device 6 so that the drainage pump 24 is drained and the water level sensor 32 again Sometimes the status of the signal is monitored.

  In addition, as a means for detecting the presence or absence of water, there is conventionally known a configuration in which two electrodes are provided and an electric resistance value between them is measured, and when it is low, it is determined that there is water between the electrodes. However, especially in a washing and drying machine, the water coming out of the dehumidifying device 6 may have a high electrical resistance equivalent to that of distilled water, and it is difficult to accurately determine whether water is present or absent. It becomes.

On the other hand, according to the configuration of the conventional example, since the thermistor 33 having self-heating characteristics is used, the electrical resistance value of water to be detected including the washing water overflowing from the washing tub 3 is obtained. Regardless of whether water is present or not, it can be accurately determined.
JP 2006-262924 A

  In the configuration of the conventional example described above, the thermistor 33 having self-heating characteristics is covered with an insulating layer, and is housed in a windbreaker constituted by a resin pipe having openings at both ends. In the dehumidifying device 6, air is circulated and moved by the air blower 12, so that when the thermistor 33 is in the air when the water level of the water storage unit 23 is low, the air flow is not applied to the thermistor 33.

  The detection of water by the thermistor 33 is based on the temperature difference between the state where the thermistor 33 is in the air and the state where it is submerged in water. Therefore, in a state where the thermistor 33 is in the air, it is desirable to weaken the flow of air hitting the thermistor 33 and to reduce the escape of heat when the thermistor 33 self-heats. By providing the windbreaker, when the water level rises to the position of the thermistor 33, the difference in the escape of heat from the thermistor 33 can be made larger than when the water level is lower than that, such as noise. It becomes possible to take a larger margin for erroneous detection of the water level due to.

  However, as described above, a water level sensor using a thermistor has a high cost for circuit parts, and is practically disadvantageous for use in a washing / drying machine.

  The present invention solves the above-described conventional problems, and provides a highly reliable washing and drying machine having a water level sensor that can reliably detect the water level in a reservoir of condensed water generated when clothes are dried with an inexpensive configuration. The purpose is to do.

  The washing / drying machine of the present invention includes a washing tub for storing and drying a cloth to be washed, a dehumidifying device for dehumidifying damp air, and the washing tub for drying the cloth. An air blower for sending humid air to the dehumidifier, a water storage unit for storing condensed water generated by the dehumidification device, a drainage device for draining from the water storage unit, and a water level sensor for detecting the water level of the water storage unit And is configured to control at least one of the operation of the dehumidifying device and the operation of the drainage device in accordance with the detection output of the water level sensor. In order to solve the above problems, the water level sensor includes a pair of water level detection electrodes disposed in the water storage section, and an oscillation circuit in which the pair of water level detection electrodes are inserted in a feedback circuit, and the water level detection electrode The presence or absence of water between the water level detection electrodes is detected based on the change in the oscillation frequency of the oscillation circuit caused by the change in the feedback current according to the electrical resistance between the water level detection electrodes.

  According to the present invention, a simple and inexpensive structure provided with a pair of water level detection electrodes is detected without being affected by circulating air and by converting a change in electrical resistance value between the electrodes into a change in oscillation frequency. Thus, the presence or absence of water can be accurately detected.

  In the washing and drying machine of the present invention, the oscillation circuit of the water level sensor includes an insulating transformer connected to a secondary side, and an AC voltage for power supply is applied to the primary side of the insulating transformer, and the power A water detection circuit for detecting a change in the frequency of the oscillation signal of the oscillation circuit superimposed on the supply AC voltage is connected, and the frequency of the power supply AC voltage is different from the oscillation frequency of the oscillation circuit. Preferably, the water detection circuit is configured to take out an oscillation signal on the primary side of the isolation transformer through a filter circuit and detect a change in the oscillation frequency of the oscillation circuit. Thereby, the water level detection electrode and power supply side which are arrange | positioned in a water storage part can be insulated, and safety can be improved cheaply.

  Further, it is preferable that a load resistance having a predetermined value is connected between the pair of water level detection electrodes. As a result, the detection range is sufficiently wide, and accurate detection is possible.

  The resistance value of the load resistance is preferably set to be equal to or greater than the electric resistance of the condensed water.

  The connectors for connecting the water level detection electrode and the oscillation circuit are each composed of two pins provided for each water level detection electrode, and the two pins on the water level detection electrode side are respectively connected to the water level detection electrode. The oscillation circuit side has one pin connected to the oscillation circuit, the other pin is electrically separated from the one pin, and the other pin is connected by the load resistor. It is preferable to have a configuration. According to this configuration, it is possible to detect forgetting to insert the connector or disconnection of the lead wire.

  In addition, one of the foam detection electrodes disposed in the washing tub and the other disposed in the vicinity of the inlet in the air passage entering the blower from the laundry tub, and an electrical resistance value between the foam detection electrodes A bubble detection circuit for detecting a change, wherein the bubble detection electrode is connected to a secondary side of the insulation transformer, and the bubble detection circuit is connected to a primary side of the insulation transformer.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic cross-sectional view of a washing / drying machine according to an embodiment of the present invention. The fundamental difference between the washing and drying machine of FIG. 1 and the conventional washing and drying machine shown in FIG. 7 is the configuration of the water level sensor. The same elements as those of the conventional example shown in FIG. 7 are denoted by the same reference numerals, and the description thereof will not be repeated.

  The water level sensor in the present embodiment has a pair of water level detection electrodes 40 a and 40 b arranged in the water storage unit 23. Although not shown in FIG. 1, the water level detection electrodes 40a and 40b are connected to the sensor circuit shown in FIG.

  FIG. 1 also shows bubble detection electrodes 41a and 41b constituting the bubble sensor. The foam sensor is used to detect a state in which washing liquid overflows from the washing tub 3 during washing and leaks into the air passage 11. Therefore, one foam detection electrode 41 a is disposed in the washing tub 2, and the other foam detection electrode 41 b is disposed in the air passage 11 near the entrance from the washing tub 2 to the air passage 11. Like the water level detection electrodes 40a and 40b, the bubble detection electrodes 41a and 41b are connected to the sensor circuit shown in FIG.

  As shown in FIG. 2, the sensor circuit includes an insulating transformer 42, and an oscillation circuit 43 and a bubble detection circuit 44 are connected to the secondary side thereof. A power supply AC voltage is applied from the power supply terminal 45 through the capacitor C1 to the primary side of the insulation transformer 42, and a water detection circuit 47 is connected through the low-pass filter 46. Further, the bubble detection output circuit 48 is connected. The reason why the insulating transformer 42 is interposed between the oscillation circuit 43 and the power supply terminal 45 is to insulate the water level detection electrodes 40a and 40b disposed in the water storage section 23 from the power source side, thereby improving safety at low cost. Because. However, the use of the insulating transformer 42 is not essential for the configuration of the water level sensor of the present invention.

  The oscillation circuit 43 includes an operational amplifier 49 for performing an oscillation operation and an operational amplifier 50 for supplying a reference voltage to the operational amplifier 49. The voltage supplied by the insulating transformer 42 is applied to the series circuit of the resistors R9 and R10 via the diode D3, and the voltage between the resistors R9 and R10 is input to the non-inverting input terminal of the operational amplifier 50, so that the operational amplifier The reference voltage supplied by 50 is determined. The operational amplifier 49 is connected to resistors R6 and R7 for determining the degree of amplification, resistors R8 and R11 for feedback, and a capacitor C3. Water level detection electrodes 40a and 40b are respectively connected to both ends of the resistor R8.

  When the water level detection electrodes 40a and 40b are immersed in water due to a rise in the water level in the water storage section 23, the electrical resistance between the water level detection electrodes 40a and 40b changes. As a result, the feedback current of the oscillation circuit 43 changes and the oscillation frequency changes. Therefore, the presence or absence of water between the water level detection electrodes 40a and 40b can be detected based on the change in the oscillation frequency.

  In order to transmit the output signal of the oscillation circuit 43 to the secondary side of the isolation transformer 42, a series circuit of a diode D3 and a transistor Q1 is connected in parallel to the primary side coil, and the output of the operational amplifier 49 is input to the base of the transistor Q1. Is done. A noise absorbing capacitor C2 is connected.

  The bubble detection circuit 44 includes a transistor Q3, resistors R12 and R13, and a capacitor C7, and bubble detection electrodes 41a and 41b are connected to the collector and base of the transistor Q3, respectively. The transistor Q3 is connected to the primary side of the insulating transformer 42.

  The low-pass filter 46 is constituted by resistors R2 and R3 and a capacitor C4, and the output thereof is supplied to the transistor Q2 constituting the water detection circuit 47. The diode D2 is provided to prevent a reverse bias from being applied to the base of the transistor Q2. The output signal of the transistor Q2 is formed into a pseudo-triangular wave with a time constant determined by the resistor R1 and the capacitor C5, is peak detected by the diode D1 and the capacitor C6, and is output from the water detection output terminal 51.

  The bubble detection output circuit 48 includes a resistor R4, a diode D5, and a capacitor C8, and outputs a DC voltage from the bubble detection output terminal 52.

  In the above configuration, the frequency of the power supply AC voltage supplied from the power supply terminal 45 and the oscillation frequency of the oscillation circuit 43 are set to be different from each other. Therefore, a signal as shown in FIG. 3A is generated at one terminal 53 of the resistance R2 on the primary side of the insulating transformer. That is, it is a waveform in which the low-frequency oscillation signal 55 from the oscillation circuit 43 is superimposed on the high-frequency power supply AC voltage 54. From this output waveform, the high frequency component of the power supply AC voltage 54 is removed by the low pass filter 46 and input to the water detection circuit 47. The pseudo-triangular wave shown in FIG. 3B is formed by the water detection circuit 47, the peak detection is performed, and the oscillation of the oscillation circuit 43 that changes from the water detection output terminal 51 due to the electric resistance between the water level detection electrodes 40a and 40b. A water detection output signal corresponding to the frequency is output.

  FIG. 4 shows the detection characteristics of the water level sensor having the above configuration. The horizontal axis represents the resistance value between the water level detection electrodes 40 a and 40 b, and the vertical axis represents the water detection voltage corresponding to the oscillation frequency of the oscillation circuit 43. The horizontal axis shows resistance values corresponding to tap water, distilled water, pure water, and no water. The water coming out from the dehumidifier 6 has a high electrical resistance equivalent to distilled water. However, as is apparent from this detection characteristic curve, there is a sufficient difference in the water detection voltage between distilled water and no water, and therefore the presence / absence of water can be accurately detected. I understand.

  For reference, the detection characteristics of the bubble detection output circuit 48 are shown in FIG. The horizontal axis represents the resistance value between the bubble detection electrodes 41 a and 41 b, and the vertical axis represents the bubble detection voltage output from the bubble detection circuit 44. There is a sufficient difference in bubble detection voltage between the absence of bubbles in the left area of the figure and the presence of bubbles in the right area of the figure, and therefore the presence / absence of bubbles can be accurately detected. This is because bubbles generated in the washing tub 2 have sufficiently low electrical resistance. It can be seen that the detection characteristic of the water level sensor is practically equivalent to the detection characteristic of the bubble detection output circuit 48.

  As described above, according to the water level sensor of the present embodiment, the presence / absence of water can be accurately detected without being affected by the circulating air unlike the water level sensor using the thermistor. It can be configured. In addition, since AC voltage is applied to the dehumidified water from the water level detection electrodes 40a and 40b instead of DC voltage, corrosion of the electrode due to electrolysis can be avoided.

  Further, by connecting the load resistance R8 between the water level detection electrodes 40a and 40b, the detection range can be widened and the detection accuracy can be improved. That is, the resistance R8 increases the slope of the detection characteristic curve shown in FIG. 4 and widens the variation range of the water detection voltage. If the resistance value of the resistor R8 is set to be approximately the same as the electrical resistance of the dew condensation water, the dehumidified water with less impurities, that is, the dew condensation water can be reliably detected.

  The resistor R13 is inserted so that the water detection output does not become 0V even when the electrical resistance between the water level detection electrodes 40a and 40b becomes 0Ω. This is to distinguish from the case where the water level detection electrodes 40a and 40b become open abnormal and the water detection output becomes 0V.

  Hereinafter, a specific structure of a connection portion between the water level detection electrodes 40a and 40b and the oscillation circuit 43 will be described with reference to FIG. The water level detection electrodes 40a and 40b are connected to the oscillation circuit 43 via connectors 56a and 56b, respectively. The connector 56a includes two pins 57 and 58 that are electrically separated from each other, and the connector 56b includes two pins 59 and 60 that are electrically separated from each other.

  Each of the water level detection electrodes 40a and 40b has a connecting portion branched into two so as to be connected to the two pins 57 and 58 and the two pins 59 and 60. The pin 57 of the connector 56 a and the pin 59 of the connector 56 b are connected to the oscillation circuit 43. On the other hand, the pin 58 of the connector 56a and the pin 60 of the connector 56b are connected to each other by a resistor R8.

  By configuring the connection part of the water level detection electrodes 40a and 40b in this way, it is possible to detect forgetting to insert the connector and disconnection of the lead wire extending from the connectors 56a and 56b to the oscillation circuit 43, thereby improving safety. .

  In the above embodiment, the case where the rotary shaft 4 of the rotary drum 2 is horizontally arranged has been described, but the present invention is not limited to the horizontal rotary shaft 4. For example, a vertical shaft that is generally referred to as a vertical shape and having a rotating drum that rotates during dehydration, or the rotating shaft 4 is provided at an angle of about 20 to 30 degrees with respect to the horizontal so that clothes can be taken in and out of the rotating drum 2. The present invention can also be applied to a structure that is easy to perform. Further, the present invention can be applied to a configuration in which components such as other mechanical parts such as a pulsator are further added to the rotating drum 2 so that effective washing can be performed during washing. .

  INDUSTRIAL APPLICABILITY The present invention can reliably detect the water level in a reservoir of condensed water generated when clothes are dried with an inexpensive configuration, and is useful for domestic and commercial laundry dryers having a dehumidifying function.

Schematic sectional view of a washing and drying machine in an embodiment of the present invention Circuit diagram showing the configuration of the water level sensor of the washing and drying machine Waveform diagram explaining the operation of the water level sensor Graph showing the detection characteristics of the water level sensor The graph which shows the detection characteristic of the bubble sensor shown in FIG. 1 and FIG. The top view of the water level detection electrode which comprises the water level sensor in the washing / drying machine of FIG. Schematic cross-sectional view of a conventional washer-dryer

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Clothing 2 Rotating drum 3 Washing tub 4 Rotating shaft 5 Motor 6 Dehumidifier 7 Compressor 8 Evaporator 9 Condenser 10 Capillary tube 11 Air passage 12 Blower 21 Drain valve 22 Drain pipe 22 Drain pipe 23 Reservoir 24 Drain pump 30 Overflow tray 31 Overflow pipe 32 Water level sensor 33 Thermistor 40a, 40b Water level detection electrode 41a, 41b Foam detection electrode 42 Insulation transformer 43 Oscillation circuit 44 Foam detection circuit 45 Power supply terminal 46 Low pass filter 47 Water detection circuit 48 Foam detection output circuit 49, 50 operational amplifier 51 Water detection output terminal 52 Bubble detection output terminal 53 terminal 54 AC voltage for power supply 55 Oscillation signal 56a, 56b Connector 57, 58, 59, 60 pins

Claims (6)

A washing tub for storing the clothes to be washed and washing and drying;
A dehumidifying device for dehumidifying damp air;
A blower that sends moist air in the washing tub to the dehumidifier when drying the cloth;
A water storage section for storing dew condensation water generated by the dehumidifier;
A drainage device for draining from the water reservoir;
A water level sensor for detecting the water level of the water reservoir,
In the washing and drying machine configured to control at least one of the operation of the dehumidifying device and the operation of the drainage device according to the detection output of the water level sensor,
The water level sensor includes a pair of water level detection electrodes arranged in the water reservoir, and an oscillation circuit in which the pair of water level detection electrodes are inserted in a feedback circuit,
A washing and drying machine that detects the presence or absence of water between the water level detection electrodes based on a change in oscillation frequency of the oscillation circuit caused by a change in feedback current according to an electrical resistance between the water level detection electrodes. The oscillation circuit of the water level sensor comprises an insulation transformer connected to the secondary side,
Connected to the primary side of the insulation transformer is a water detection circuit for detecting a change in the frequency of the oscillation signal of the oscillation circuit superimposed on the AC voltage for power supply while being applied with an AC voltage for power supply. And
The frequency of the power supply AC voltage and the oscillation frequency of the oscillation circuit are set to different frequencies,
The washing / drying machine according to claim 1, wherein the water detection circuit takes out an oscillation signal on a primary side of the insulation transformer through a filter circuit and detects a change in an oscillation frequency of the oscillation circuit.   The washing / drying machine according to claim 1, wherein a load resistance having a predetermined value is connected between the pair of water level detection electrodes.   The washing / drying machine according to claim 3, wherein a resistance value of the load resistance is set to be equal to or greater than an electric resistance of the condensed water.   The connectors for connecting the water level detection electrode and the oscillation circuit are each composed of two pins provided for each water level detection electrode, and the two pins on the water level detection electrode side are respectively connected to the water level detection electrode. The oscillation circuit side has one pin connected to the oscillation circuit, the other pin is electrically separated from the one pin, and the other pin is connected by the load resistor. The washing / drying machine according to claim 3. One is arranged in the washing tub, and the other is a pair of foam detection electrodes arranged in the vicinity of the inlet in the air passage entering the blower from the washing tub, and a change in electric resistance value between the foam detection electrodes. A bubble detection circuit to detect,
The washing / drying machine according to claim 2, wherein the foam detection electrode is connected to a secondary side of the insulation transformer, and the foam detection circuit is connected to a primary side of the insulation transformer.

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