JPH02126895A - Rinsing control device for full-automatic washing machine - Google Patents

Abstract

PURPOSE:To prevent the corrosion of an electrode and the electrification of a user by detecting the electrostatic capacity of a solution exhausted from a washing and drying tank at the time of drying by a non-contact electrode and controlling the rinsing step. CONSTITUTION:An electrostatic capacity detecting unit 13 installed to a water receiving tank 2 to detect the electrostatic capacity of the solution in the water receiving tank 2 is formed of a non-conductive case 13a and parallel electrodes 13b, 13d stuck to the side surface thereof. When the drainage in a first rinsing is completed, the electrostatic capacity detecting unit 13 contains the air and the inter-electrode capacity is small, so that the frequency of a detection circuit 22 is made maximum. At the time of drying, a solution containing bubbles and a detergent is drained from a washing and drying tank 3 and sent into the electrostatic capacity detecting unit 13, and thus the frequency is reduced. At the beginning of the middle drying, a periodical intermittent drying is conducted. Thus, as the rotation speed of the washing and drying tank 3 is accelerated to increase the drained liquid quantity in the ON- condition, the frequency is reduced. Contrary to this, in the OFF-condition, the frequency is increased, as the drained liquid quantity is reduced. Hence, a control means 23 controls the rinsing step based on the output signal of the detection circuit 22 in the drying time of the rinsing step.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a rinsing control device for a fully automatic washing machine in which a water receiver detects a change in the state of liquid in a tank as a change in capacitance and controls the rinsing process. It is related to.

Prior Art Conventionally, this type of rinsing control device was developed by Japanese Patent Publication No. 62-71.
As disclosed in Japanese Patent No. 9, an electrode is provided to protrude from the inner wall of the outer tank to measure the conductivity of tap water or washing liquid to determine whether rinsing is complete.

Problems to be Solved by the Invention In the conventional rinsing control method described above, the electrode must be brought into direct contact with tap water or washing liquid, so the surface of the electrode corrodes over time, resulting in incorrect conductivity values. may not be obtained, making it impossible to determine when the rinse is complete, or
Alternatively, there was a problem that the rinsing end point was not accurate. In addition, since the electrodes are energized and AC 1oov is normally applied to the ground, there is a risk of electric shock if the user touches the water or washing liquid in the outer tank.

SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned conventional problems, and aims to prevent electrode corrosion and electric shock to the user.

Means for Solving the Problems To achieve this object, the present invention provides a water receptacle for storing washing water, a tank, a pair of electrodes attached to the tank,
and a detection circuit that generates an electrical signal using the capacitance between the electrodes as part of the circuit.

A control means for controlling rinsing, dehydration, etc. is provided, and the control means is configured to control the rinsing step based on an output signal of the detection circuit during dehydration in the rinsing step.

Function According to the above configuration, the rinsing process can be controlled by detecting the rinsing condition with an electrode that does not come into contact with tap water or washing liquid, so it is possible to prevent the electrode surface from corroding over time and prevent malfunction. be able to. Furthermore, even if the user touches the water or washing liquid in the outer tank, he or she will not receive an electric shock.

EXAMPLE Hereinafter, an example of the present invention will be described with reference to the drawings.

Figure 1 is a cross-sectional view of a fully automatic washing machine. 1 is an outer frame, 2 is a water tray, 3 is a washing and dehydrating tub, 6 is a rotary blade 4 during washing or rinsing, and washing is during spin-drying. This is a power switching mechanism for switching the power of the washing/extracting motor 6 so as to rotate the washing/extracting tank 3. Reference numeral 7 designates an air reservoir that generates a pressure corresponding to the water level, 9 an air hose for transmitting the pressure generated in the air reservoir 7 to the water level detection means 8, and 10 a water receiver that collects the liquid in the tank 2. Drain valve for discharging to the outside, 11 is a drain hose, 12 is a water receiver for tap water, tank 2
A water supply valve 13 is a capacitance detection unit attached to the tank 2 to detect the capacitance of the liquid in the tank 2. Capacitance detection unit 13
As shown in FIG. 2, it is composed of a non-conductive case 13a and parallel electrodes 13b and 13c attached to the sides thereof.

The case 13a is hollow so that the liquid in the tank 2 can enter, and the upper part is designed to prevent bubbles from accumulating during washing or rinsing, and the lower part is designed to prevent liquid from accumulating during draining or dewatering. Furthermore, the amount of liquid discharged from the washing and dehydration tank 3 during dehydration is larger at the bottom.
The case 13a has a structure in which a water receptacle is attached to the bottom of the tank 2.

Further, the capacitance detection unit 13 is a part of the detection circuit shown in FIG. In the figure, 22a is an inverter, 2ab is a feedback resistor, 22c is a coil, and 22d is a capacitor.Oscillation is caused by the inductance L of the coil 22c, the combined capacitance C of the capacitance detection unit 13, and the capacitor 22d. When the properties of the liquid in 2, that is, the specific inductivity, change, the capacitance detection unit 1
Since the capacitance of 3 changes, the output frequency of the detection circuit 22 also changes.

Next, the main circuit configuration of the fully automatic washing machine will be explained with reference to FIG. In the figure, 14 is washing and rinsing.

Input means for setting which dehydration process to operate, water level, etc.; 15, display means for informing the user of the contents set by the input means 14, the progress of washing, etc.; 8;
The water receiver is a water level detection means for detecting the water level in the tank 2 and generating an electric signal, 16 and 17 are bidirectional thyristors for driving the washing and dewatering motor 6, and 18 is for driving the water supply valve 12. bidirectional thyristor, 19 is the drain valve 10
2o is a commercial power supply, 21 is a power switch, 22 is a detection circuit, and 23 is a control means for inputting the output frequency signal of the detection circuit 22 to control the operation of the rinsing process, etc. It is.

FIG. 6 shows the detailed operations of the fully automatic washing machine having the above structure, from washing to spin-drying. How the output frequency (hereinafter simply referred to as frequency) of the detection circuit 22 changes during the intermediate dehydration of the first rinse will be explained based on FIG. 6.

At the end of drainage, the inside of the capacitance detection unit 13 is air, and the dielectric constant of air is as small as 1, and the interelectrode capacitance is Case 1.
The capacitance of capacitance 3a and the capacitance of air become a series composite capacitance, which becomes very small, and the frequency becomes maximum, and this value is set as fo. During dehydration, a liquid containing foam and detergent is discharged from the washing and dehydrating tank 3 and flows through the capacitance detection unit 13, so the capacity becomes larger and the frequency becomes lower than when using air. This is because the dielectric constant of water is as large as about 80, and if detergent is contained, the ions therein will be polarized, making the dielectric constant apparently even higher. Therefore, if the amount of liquid in the capacitance detection unit 13 is the same, the more detergent it contains, the larger the capacity and the lower the frequency. Therefore, when a large amount of detergent is contained, the characteristics are shown by the solid line in the figure, and when only a small amount of detergent is contained, the characteristics are shown by the broken line. Also, at the beginning of intermediate dehydration, 0N is periodically applied.
- It is an intermittent dehydration that repeats OFF, and when it is ON, the rotation speed of the washing/dehydration tank 30 is accelerated and the amount of liquid discharged increases, so the frequency decreases, and conversely, when it is OFF, the amount of liquid discharged is As it decreases, the frequency increases. Also, from ON to 0FFK
Since the amount of liquid in the capacitance detection unit 13 reaches its peak a little later after the switch is turned off, the frequency reaches its minimum a little later from the moment the power is turned off. As dehydration progresses, the amount of liquid discharged decreases, so the minimum value of the frequency increases.

Based on the above principle, a method of detecting during intermediate dehydration of the first rinsing and controlling subsequent rinsing steps will be described with reference to the flowchart of FIG. 7. The control means 23 turns on the bidirectional thyristor 19 in step 100, thereby turning on the drain valve 1o and starting draining. Next, in step 101, the water level detection means 8 determines whether or not drainage is completed. If drainage is completed, step 102 and step 1
In 03, N==o, f,=O. Next step 104
The frequency of the detection circuit 22 when the inside of the capacitance detection unit 13 is air is measured, and this value is set as fo. Then, in step 106 and step 106, the ON time is T
. n, perform intermittent dehydration once with an OFF time of "off".The frequency is not measured at this time because the first O
This is because at N, a large amount of bubbles are discharged and the frequency becomes unstable, so this value is ignored. Step 107 below
to 114, and the ON time is T. n, OFF time”
OFF intermittent dehydration is performed four times, and the frequency of the detection circuit 22 is measured four times after Ta has elapsed since turning OFF, and these values are added to obtain f8. Here “a”
” ”b ””of f. And step 11
6 to step 119, if fo-f8/4<Δ9, the amount of detergent used is considered to be a small amount, and subsequent rinsing is performed in the rinse A course shown in FIG. 8, Δfa≦f0f, /4
If <Δfb, the amount of detergent used is considered to be medium, and subsequent rinses are performed in the same B course, Δfb≦f0-f,
/4, the amount of detergent used is considered to be large, and subsequent rinsing is performed in the same C course.

In this example, the minimum value of the detection circuit after the second cycle during intermittent dehydration was measured four times, and the average value of these values and f
Although the method is to compare fo with the minimum value of the detection circuit a little after 0FFI in the second cycle, it is equally effective. Further, although the method is described in which detection is performed during the intermediate dehydration of the first rinse, the same effect can be achieved by detecting during the intermediate dehydration of the second rinse and controlling the subsequent rinsing process.

In addition, in this embodiment, when water is intermittent during a predetermined period after the start of dehydration, the minimum value of the frequency change is determined by reading the frequency of the detection circuit a little while after the dehydration motor is turned off. Since it is read, the detection accuracy improves.

Effects of the Invention As is clear from the above embodiments, according to the present invention, the rinsing process is controlled by detecting the capacitance of the liquid discharged from the washing and dehydrating tank using non-contact electrodes during dehydration. , the electrode can be made non-contact with the liquid, eliminating the risk of corrosion of the electrode and electric shock to the user.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a fully automatic washing machine according to an embodiment of the present invention, FIG. 2 is a perspective view of a capacitance detection unit according to an embodiment of the present invention, and FIG. 3 is a cross-sectional view of a fully automatic washing machine according to an embodiment of the present invention. 4 is a block diagram of a fully automatic washing machine according to an embodiment of the present invention; FIG. 5 is a process diagram of a fully automatic washing machine according to an embodiment of the present invention; and FIG. A characteristic diagram during the rinsing process of an embodiment of the invention,
FIG. 7 is a flow chart of one embodiment of the present invention, and FIG. 8 is a diagram showing a rinsing course of one embodiment of the present invention. 2... Water receiver is tank, 13... Capacitance detection unit, 13b, 13a... Electrode, 22...
...Detection circuit, 23...Control means. Name of agent: Patent attorney Shigetaka Awano and 1 other person! Illustrations 13b, 19C-Ichiyake Port Map, Dot and Hanging Map, Time Chart

Claims (1)

[Claims] A water tank for storing washing water, a pair of electrodes attached to the water tank, a detection circuit that generates an electric signal using the capacitance between the electrodes as part of the circuit, and washing, rinsing, dehydration, etc. A rinsing control device for a fully automatic washing machine, comprising a control means for controlling the rinsing process, the control means controlling the rinsing process based on an output signal of the detection circuit during dehydration during the rinsing process.