JPH0728982B2 - Washing machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a washing machine equipped with a device for detecting the concentration of washing liquid.

(B) Prior art A washing machine of this type is disclosed in Japanese Patent Laid-Open No. 56-11097, which has a pair of light emitting element and light receiving element for detecting the transparency of the washing liquid. A device, a calculator that divides the transparency of the washing liquid and water used for washing during the rinsing stroke detected at different times in a series of washing strokes, and a comparator that compares the output of this calculator with a reference value. Be prepared.

However, since the transparency detection device is usually fixed below the lowest water level in the washing tub and generally foaming is likely to occur near the water surface, the lower the water level is, the more easily it is affected by the foam, and therefore the reference value. If is constant, there will be a difference in the detection results between the low water level and the high water level.

(C) Problem to be Solved by the Invention The present invention is to provide a washing machine capable of performing accurate washing liquid concentration determination at each water level without being affected by bubbles and the like, and thus performing appropriate washing. It is what

(D) Means for Solving the Problems The present invention is directed to a water tank, a blade arranged in the water tank, a drive motor for driving the blade, and a water supply valve provided in a water supply path for supplying water into the water tank. And a water level setting button for setting the water level in the water tank, a water level detector for detecting the water level in the water tank, the water level setting button, the drive motor based on signals from the water level detector, a water supply valve, etc. And a concentration detecting device for detecting the concentration of the washing liquid is attached to the lower part of the water tank, and the microcomputer compares the detection output of the concentration detecting device with a reference value. In a washing machine having a built-in comparator and judging a concentration rank based on a comparison result of the comparator, the reference value is changed based on a water level.

(E) Action That is, even if the actual concentration is the same, the detection output that is winged by the water level is measured due to the effect of bubbles, so the reference value to be compared should be changed according to the water level. Due to
This is to correct the detection result.

(F) Embodiments Embodiments of the present invention will be described with reference to the drawings.

In the fully automatic washing machine of FIG. 3, (1) is a machine frame, (2)
Is an operation part provided in the upper rear part of the machine casing (1), (3) is an outer tank installed in the machine casing (1), (4) is installed in the outer tank (3), and is dehydrated in the surroundings. An inner tank having holes (5) ..., (6) a rotary blade arranged at the bottom of the inner tank (4), and (7) a drive motor for the inner tank (4) and the rotary blade (6). The rotor (6) is connected through a power transmission mechanism (8) and is rotated during washing, and both the inner tub (4) and the rotor (6) are rotated at high speed during dehydration. (9) is a drain port provided at the bottom of the outer tank (3), (10) is a drain solenoid valve, (11) is a drain hose, (12)
Is an air trap provided at one corner of the bottom of the outer tub (3) and communicates with the pressure switch (13) in the operation section (2) via a pressure hose (14). (15) is a solenoid valve for water supply provided in the water supply channel (16), and (17) is a concentration detector attached to the lower part of the inner wall of the outer tank (3) so as to face the outer wall surface of the inner tank (4). It is a device.

FIG. 4 shows a block circuit diagram of the control mechanism, in which (18) is a microcomputer which is the center of control, and includes a pressure switch (13), a concentration detecting device (17), a water level setting button (19) and various operation switches. When a signal is input from the operation unit (20) composed of, the display circuit (2
1), a buzzer circuit (22) for notifying the end of the process, a drive circuit (23) for the drive motor and a supply / drainage solenoid valve drive circuit (24)
Control each operation of. The respective input signals from the concentration detecting device (17) at different times are calculated by the calculator (25) in the microcomputer (18) and the ratio between them is calculated by the comparator (26). Determine the rank of density by comparing with the standard value.

Next, the density detecting device (17) will be described with reference to FIGS. 1 and 2.

(27) is a transparent window flush with the inner wall of the outer tank (3) (provided that the location is below the reset point of the pressure switch (13)), and (28) is the transparent window (27). ) Is a sensor holder attached to the outer surface of the
The light receiving element (30) located at the center between the light emitting element (29) and the light emitting elements (29) is disposed. The emitted light is reflected on the lower part (4a) of the outer wall surface of the inner tank (4), and the light receiving element (3
The angle is adjusted so that each of them is incident on (0). (31) is a cover of the sensor holder (28), and (32) is a water sealing member.

Here, a light emitting diode that emits green light is used as the light emitting elements (29), and an amorphous visible light full spectrum sensor is used as the light receiving element (30).

As shown in FIG. 6, the amorphous visible light full spectrum sensor exhibits a spectral sensitivity characteristic very close to human visual sensitivity, and the sensitivity peak is almost equal to the wavelength of green light (about 5500Å), And the sensitivity is very good.

The output of the light receiving element (30) is amplified by an operational amplifier by the circuit shown in FIG. 5, and then input to the microcomputer (18) as a control output signal.

Thus, in the washing and rinsing steps, the washing liquid in the tub is agitated with the laundry by the rotary blades (6).

FIG. 7 shows a general output characteristic of the light receiving element (30) during the washing process. As the detergent dissolves and the dirt floats, the washing liquid becomes turbid and the output decreases.

According to Beer's law, the following relation holds when light passes through a solution.

Is / Io ＝ e ^-kcd (1) where, Io: intensity of light emitted from the light source, Is: intensity of light received by the light receiving element, C: concentration of solution, K: extinction coefficient, d : Length of liquid layer In addition, although the above formula (1) is strictly discussed only for monochromatic light, it is approximately applicable to visible light.

Now, in FIG. 8, assuming that (i) is at the start of washing and (b) at the time t ₁ after the start of washing, Is / Io = e− ^{(k0 + α) c} from the equation (1). (2) Is' / Io = e- ^{(k1 + α) c} (3) α: Absorption coefficient that depends on dirt on the wall surface. Since d is constant, it is set to 1 for convenience.

Wherein (2), (3) and from the relationship of the sensor, LnV = PLnIs + A = PLnIoe - (k0 + α) c + A ...... (4) LnV 1 = PLnIs' + A = PLnIoe - (k1 + α) c + A ...... (5 ) P: Amplification of detection circuit, A: Voltage correction value caused by dark current V / V ₁ = e ^{P (k1-k0) c} …… (6) From the above equations (4) and (5) It can be understood that the ratio of the sensor output voltage at different times in the liquid depends on the magnitude of the concentration C of the solution. In addition, the equation (6) is the difference between the respective extinction coefficients (K ₁ -K ₀ ).
It also depends on the size of. Generally, the higher the detergent concentration, the more frequently foaming occurs, and the effects of foaming increase the values of K ₁ and K ₀ . In particular, with time, the degree of foaming also increases, and K ₁ is more strongly affected by foaming than K ₀ , and therefore (K ₁ −K ₀ ) becomes larger.

Usually, the bubbling is likely to occur near the water surface, and the concentration detecting device (17) is fixed to the lower part of the outer layer (3), that is, a place relatively close to the lowest water level surface. In the case, the influence of foaming is stronger than that in the case of high water level, and the above (K ₁ -K ₀ ) also becomes larger.

In this way, there is a difference in the degree to which the bubbling is affected by the water level. Therefore, even if the concentration is the same, there will be a difference in the output from the computing unit (25), and if the reference value is constant, it is inevitable. An error occurs in the concentration detection result. Therefore, it is necessary to set the reference value according to the water level.

FIG. 9 is a graph in which a reference value corresponding to the water level is obtained by an experiment, and the detection output V ₂ at time t ₂ (t ₂ > t ₁ ) is further used, and V ₀ / V ₂ − V ₀ / V ₁ = a on the horizontal axis, V ₀ / V ₂ = b
Is plotted on the vertical axis, and three levels of detergent concentration (concentration (concentration 0.14%), appropriate (concentration 0.07%), light (concentration 0.035) at each water level are taken.
%)) Is plotted. As a result, the standard values shown in Table-1, Table-2 and Table-3 have been determined.

Thus, the respective reference values are set at the same time as the setting of the water level,
The user may add detergent or replenish water with reference to the detected and displayed concentration rank.

Although the present embodiment has been described by taking the washing process as an example, the rinsing process is not so affected by foaming as the washing process, but can be sufficiently applied. However, it is necessary to use a standard value different from that used in the washing process.

As described above, in this embodiment, the concentration of the washing liquid is detected in consideration of the water level, and since the green light emitting diode and the amorphous visible light full spectrum sensor are used for the concentration detection device, it matches the appearance of the user. The density can be detected, and light having a shorter wavelength than infrared is used, and the light is relatively hard to be absorbed by the washing liquid or the laundry, and the decrease in sensitivity can be suppressed accordingly.

FIG. 10 shows that in another embodiment, the reference value is determined by the same experiment, the concentration is plotted on the horizontal axis (logarithmic scale), and the output ratio V ₀ / V ₁ of the sensor is plotted on the vertical axis. When conducting a sampling experiment, the characteristics shown in the figure are obtained depending on the water level. Therefore, the reference values shown in Tables 4 to 6 can be set.

(G) Effect of the Invention In the present invention, in a washing machine equipped with a device for detecting the concentration of a washing liquid, a reference value serving as a reference for concentration determination is individually set according to each set water level, so the water level is considered. It is possible to perform the accurate concentration detection described above, and suppress variations in concentration determination between different set water levels.

Therefore, the washing suitable for the laundry can be performed.

[Brief description of drawings]

FIG. 1 is a side sectional view of a concentration detecting device in a washing machine of the present invention, FIG. 2 is a plan view of a light emitting and receiving element, FIG. 3 is a sectional view of a washing machine, and FIG. 4 is a block diagram of a control mechanism. , FIG. 5 is a circuit diagram of the concentration detecting device, FIG. 6 is a spectral sensitivity characteristic diagram of the amorphous visible light full spectrum sensor, FIG. 7 is an output characteristic diagram of the amorphous visible light full spectrum sensor in the washing step, and FIG. Figures (a) and (b) show the principle of light transmission in liquid, and Figures 9 (a), (b), and (c) show the output characteristics of the concentration detector at each concentration and set water level. FIG. 10 and FIG. 10 correspond to FIG. 9 in another embodiment. (17) ... Concentration detection device, (19) ... Water level setting button, (26) ...
Comparator, (29) ... Light emitting element, (30) ... Light receiving element.

Claims (1)

[Claims] 1. A water tank, blades arranged in the water tank, a drive motor for driving the blades, a water supply valve provided in a water supply passage for supplying water into the water tank, and a water level in the water tank is set. A water level setting button, a water level detector for detecting the water level in the water tank, and a microcomputer for driving and controlling the drive motor, the water supply valve, etc. based on signals from the water level setting button, the water level detector, etc. Further, a concentration detecting device for detecting the concentration of the washing liquid is attached to the lower part of the water tank, and the microcomputer has a built-in comparator for comparing the detection output of the concentration detecting device with a reference value and the comparator. The washing machine for determining the concentration rank based on the comparison result of 1., wherein the reference value is changed based on the water level.