JPS624999B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In general, there are many types of detergents, each of which has a different turbidity. When the end of washing is detected by a change in the turbidity of the washing liquid during washing, when it is easy to detect a change in turbidity during washing depending on the turbidity of the detergent liquid,
There are times when it is difficult to do so. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to make it possible to detect a change in turbidity of a washing liquid during washing, regardless of the turbidity of the washing liquid, regardless of the detergent used.

Conventionally, washing machines are operated for a fixed period of time using a time switch. Therefore, it has the disadvantage that it takes unnecessary time and damages the fabric. Therefore, as a method of detecting washing of a washing machine, a method of detecting the dirtiness (turbidity) of the liquid during washing can be considered. As a method for measuring turbidity, there is a method of measuring turbidity by measuring the light transmittance of a liquid using a light emitting element and a light receiving element. According to this method, it is possible to detect a change in the turbidity of the washing liquid during the washing process, and it is possible to detect the end of washing. However, detergents currently on the market include detergents that contain phosphorus (phosphorus-containing detergents) and detergents that do not contain phosphorus (phosphorus-free detergents). Among these, phosphorus-free detergents include powdered soap, liquid detergent, other synthetic detergents, and many other detergents. When each type of detergent is dissolved in water, the turbidity of the detergent solution differs, especially between phosphorus-containing detergents and phosphorus-free detergents. Phosphorus-free detergents have high turbidity, while phosphorous detergents have low turbidity. Therefore, even if it is possible to detect changes in the turbidity of the washing liquid during the washing process with a phosphorus-containing detergent, if a detection element with the same sensitivity characteristics is used, with a phosphorus-free detergent, the turbidity of only the detergent liquid is high. Moreover, it is difficult to detect changes in turbidity during the washing process. In other words, there is a problem in that some detergents are difficult to detect depending on the type of detergent.

The present invention solves the above-mentioned drawbacks, and includes:
One embodiment will be described below based on the accompanying drawings. In the figure, 1 is a washing machine main body, and 2 is an outer tub, which is suspended and supported within the washing machine main body 1 by four rods 3, and has a vibration-proof structure. Reference numeral 4 denotes a washing tub that also serves as a spin-drying tub and has a large number of holes in the wall. Numeral 5 is a pulsator that rotates forward and backward, and is used to wash the clothes in the washing tub 4. 6 is a motor, and 7 is a detection case attached to a part of the outer tank 2. Inside this detection case 7, a light emitting element and a light receiving element are provided facing each other at a constant interval. 8 is the light emitting element described above, and 9 is the same light receiving element. The switch S ₁ switches the resistors R ₁ and R ₂ in order to change the amount of light emitted from the light emitting element 8.
The switch S ₂ is used to switch the resistors R ₃ and R ₄ in order to change the light receiving sensitivity of the light receiving element 9. The characteristics of the element are switched by detecting the initial turbidity of the washing liquid with the light receiving element 9 during the stop time of the pulsator 5 after a certain period of time has elapsed after the start of washing, and converting the initial turbidity of the washing liquid to the set value by the comparison part 11 via the amplifying part 10. The controller 12 operates the relay _Ry to automatically switch the switches S ₁ and S ₂ if a switch is necessary. In the figure, 13 is a drain valve, and 14 is a drain hose.

The operation in the above configuration will be explained. In FIG. 2, when switch S ₁ is connected to resistor R ₁ and switch S ₂ is connected to resistor R ₃ , the characteristics of the sensing element are as shown in FIG. 3a. Next, when switch S ₁ is connected to resistor R ₂ and switch S ₂ is connected to resistor R ₄ , the characteristics shown in b are obtained. In addition, laundry detergents include detergents that contain phosphorus (phosphorus-containing detergents) and detergents that do not contain phosphorus (phosphorus-free detergents). Approximately 220ppm (0.133% concentration) for phosphorus-containing detergents.
It is 20-40ppm (0.133% concentration). When washing with a phosphorus-containing detergent, connect switches S ₁ and S ₂ to resistors R ₁ and R ₃ , respectively, and detect with the sensitivity of the detection element of characteristic a in Fig. 3, graph c in Fig. 4 As washing progresses, dirt falls off from the clothes, the turbidity of the washing liquid increases, and the output voltage increases. Therefore, by detecting a place where the turbidity change is stable, the completion of washing can be detected.

Next, when washing with a phosphorus-free detergent, the turbidity of the washing liquid made by dissolving the phosphorus-free detergent in water is approximately 220 ppm.
There is also. If the sensing element has characteristic a in Figure 3, the increase in output voltage will be large in response to an increase in turbidity until the turbidity reaches about 250ppm, but once it exceeds 250ppm, the increase in output voltage will be large in response to an increase in turbidity. becomes smaller. For this reason, when using a phosphorus-free detergent, if you try to detect it with the sensitivity of characteristic a in Figure 3, the result will be as shown in d in Figure 4, and even if the turbidity increases, the output voltage will increase less and washing will end. is difficult to detect. Therefore, when a phosphorus-free detergent is used, switches S ₁ and S ₂ are connected to resistors R ₂ and R ₄ , respectively, and detection is performed with the sensitivity of characteristic b shown in FIG. Characteristic b, contrary to characteristic a, has turbidity.
Below 250ppm, the increase in output voltage is small;
At 250 ppm or more, the increase in output voltage becomes large with respect to the increase in turbidity. Therefore, when detecting with characteristic b, the output voltage temporarily decreases by switching from characteristic a in Figure 3 to characteristic b at point D, as shown in e in Figure 4, but after that, the output voltage does not increase. , it is possible to detect the end of washing. In addition, switches S ₁ and S ₂
It is not necessarily necessary to switch both at the same time, and only one may be switched.

To determine whether to switch the characteristics of the sensing element,
The turbidity of the washing liquid is detected within the pulsator stop time after a certain period of time has elapsed after the start of washing, and the determination is made based on the magnitude of the turbidity. This is because it takes several tens of seconds or more for the detergent to uniformly dissolve into the liquid in the outer tank 2, and within this time, the detergent will not dissolve into the liquid.
This is because the concentration of the detergent liquid becomes lower than the actual concentration of the detergent liquid, and the characteristics of the detection element that should be switched do not switch, and it may not be possible to accurately detect changes in the turbidity of the washing liquid. be.

Although the description has been made regarding a single-tub type washing machine, the same applies to a two-tub type washing machine.

As is clear from the above embodiments, the automatic washing machine cleaning detection method of the present invention has the following excellent effects.

1. By keeping the distance between the light-emitting element and the light-receiving element constant and changing the sensitivity characteristics of the detection element, changes in turbidity during the washing process can be detected regardless of the concentration or type of detergent.

2. Since the distance between the light emitting element and the light receiving element is kept constant, the structure of the detection section is simplified.

3 The initial turbidity is detected after stirring for a certain period of time, which means that the detergent dissolves in the water and
By detecting the washing liquid after it reaches a uniform concentration, the turbidity of the washing liquid can be detected accurately.

4. Even if the turbidity of the washing liquid is low, if the laundry is heavily soiled, it is necessary to change the sensitivity characteristics. Even in this case, after stirring for a certain period of time,
If the initial turbidity is detected, the sensitivity characteristics can be switched and accurate turbidity detection can be performed.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of an automatic washing machine according to an embodiment of the present invention, Fig. 2 is a circuit diagram of the detection element, Fig. 3 is a characteristic diagram showing the sensitivity of the detection element, and Fig. 4 is the output voltage during the washing process. Turbidity change diagram showing changes in . 4...Washing tub, 5...Pulsator, 8...Light emitting element, 9...Light receiving element, _S1 , _S2 ...Switch.

Claims (1)

[Claims] 1. A detection element equipped with a light-emitting element and a light-receiving element is installed to detect changes in the turbidity of the washing liquid, and after stirring the washing liquid for a certain period of time after the start of washing, the detection element detects the initial turbidity of the washing liquid. A cleaning detection method for an automatic washing machine that changes at least one of the light emission amount of a light emitting element of a detection element or the light receiving sensitivity of a light receiving element according to initial turbidity.