JPS61232895A - Apparatus for detecting turbidity in washing machine - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a washing machine that controls washing operations by detecting changes in water turbidity, and particularly to a turbidity detection device for the washing machine.

(Prior art and its problems) First, an example of this type of washing machine will be described with reference to FIG. FIG. 7 is a block diagram showing the control system of a conventional fully automatic washing machine, in which 1 is an outer tank, 2 is a water tank, 3 is an inner tank that serves as a dehydration and washing tub, 4 is a pulsator, 5 is a conduction pipe, and 6 1 is a sensor that optically detects the turbidity of water by a combination of a light emitting element and a light receiving element, 7 is a conduit pipe for draining water from the tank, 8 is a motor, 9 is a motor control unit, and 10 is a sensor from sensor 6. a turbidity detection unit that detects a change in turbidity based on a signal; 11 is a drain valve;
12 indicates a drain valve control section, 13 indicates a sequence control section,
When the motor 8 is driven to rotate the pulsator 4, the inner tank 3
The water inside circulates in a circulation path consisting of the outer tank 1, the continuous pipe 5, the conductor pipe 7, and the outer tank 1 as shown by the arrow in the figure, and the sensor 6 detects the turbidity of the water. Furthermore, sensor 6
The change in turbidity of water in the inner tank 3 is approximately equal to the change in turbidity of water in the inner tank 3, although there is a slight delay in response.

By the way, when the motor or pulsator is driven in reverse to obtain reversed water flow with high cleaning efficiency, a lot of bubbles are generated in the inner tank, which pass through the circulation path and reach a part of the sensor, resulting in a high detergent concentration. Especially when the water level is low, there will be a lot of foam, which will interfere with the sensor's ability to detect turbidity. That is, when bubbles enter the optical path of the sensor, the light is diffusely reflected by the bubbles, reducing the transmittance, making it impossible to accurately detect changes in water turbidity, and making it extremely difficult to determine whether washing is complete.

(Objective of the Invention) The present invention has been made in view of the above problems, and by preventing bubbles from entering a part of the sensor, it is possible to accurately detect changes in turbidity and accurately determine the end of washing. The present invention provides a turbidity detection device.

(Structure of the Invention) The present invention provides a washing machine that is provided with a sensor that optically detects the turbidity of water and that controls the washing operation based on a signal from the sensor. and,
a bubble trap inserted into the circulation path, the bubble trap having a passage cross-sectional area larger than that of the circulation path, the inlet side being located above the outlet side, and the sensor being disposed near the outlet of the bubble trap. By using the provided configuration,
It accomplishes the intended purpose.

(Embodiments) The embodiments of the present invention shown in FIGS. 1 to 6 will be described in detail below.

First, FIG. 1 is a block diagram showing the control system of a fully automatic washing machine according to an embodiment of the present invention. Similarly to FIG. 7, 1 is an outer tub, 2 is a water tank, and 3 is an inner tub (washing tub). , 4 is a pulsator,
7 is a conduction pipe, 8 is a motor, 9 is a motor control section, 11 is a drain valve, 12 is a drain valve control section, and 13 is a sequence control section.

14 has an inlet 15 at the top and an outlet 16 at the bottom, and connects the inlet 15 to a communication port 18 on the side of the outer tank 1 via a communication pipe 17.
Then, the outlet 16 is connected to the drain valve 1 of the conduction pipe 7 via the communication pipe 19.
1 and the drain port 20, the cross-sectional area of the passage is larger than that of the communication pipe 17 that forms part of the circulation path, and the ceiling wall is sloped upward from the outlet 16 toward the inlet 15. It's a shame. 21 is the outlet 16 of the foam trap 14
A washing sensor 22 installed nearby is a rinsing sensor installed near the inlet 15 of the foam trap 14. Both sensors 21 and 22 optically measure water turbidity by a combination of a light emitting element and a light receiving element. It is something that can be detected. 23 indicates a turbidity detection section.

In the above configuration, when the pulsator 4 is rotated, the inner tank 3
The water inside circulates through a circulation path consisting of the outer tank 1, the continuous pipe 17, the foam trap 14, the continuous pipe 19, the conductive pipe 7, and the outer tank 1, as shown by the arrow in the figure.

Therefore, during washing, the washing water in the inner tub 3 flows from the outer tub 1 through the communication pipe 17 into the foam trap 14 due to the rotation of the pulsator 4, where the flow rate is rapidly reduced. That is, since the passage cross-sectional area of the bubble trap 14 is larger than that of the communication pipe 17, the flow rate of the washing water is reduced. Then, the foam A mixed in the washing water will collect on the inner surface of the ceiling wall of the foam trap 14 due to its own buoyancy, and only the washing water containing no foam will flow from the outlet 16 to the communication pipe 19, the communication pipe 7, and the outside. It circulates through tank 1 to inner tank 3. Then, the foam A gathered on the inner surface of the ceiling wall of the foam trap 14,
During the pause period between when the bubble stops and when it is next reversed, the bubble floats from the inlet 15 through the communication pipe 17 guided by the slope of the ceiling wall and returns to the outer tank 1, causing the bubble trap 14 to be filled. There isn't.

Figure 2 is an output characteristic diagram of the turbidity detection unit 23 when the water permeability is detected by both sensors 21 and 22, and Figure 3 is a diagram of the output characteristics of the washing sensor 23 when washing with washing water with a high detergent concentration.
FIG. 4 is an output characteristic diagram of the turbidity detection unit 23 when turbidity is detected by 1, and FIG. 4 is an output characteristic diagram when turbidity is detected by the rinsing sensor 22 during the same washing.

As is clear from the output characteristics in Figure 3, the washing sensor 21 does not have diffused reflection of light due to the inclusion of bubbles.
The output of the turbidity detection unit 23 shows a smooth time change curve, and in this method, the end of washing is determined by detecting that the turbidity change ΔV per unit time has become less than a predetermined value. It can be seen that the turbidity detection by the sensor 21 is extremely convenient. On the other hand, in the rinsing sensor 22 part, diffuse reflection of light occurs due to the inclusion of bubbles, so the turbidity detection part 2
The output change in No. 3 is irregular as shown in Figure 4, and it is unclear whether the change is due to diffused reflection from bubbles or turbidity, and it is difficult to determine whether the change in turbidity is due to the turbidity change per unit time. It is not possible to accurately determine the end of the process.

Next, in the case of rinsing, since there is almost no turbidity due to dirt as there is during washing, it is necessary to judge whether rinsing is complete based on the residual detergent content (white turbidity and foam due to detergent content) in the rinsing water. By the way, the washing sensor 21 cannot detect the presence of foam because no foam is mixed in, and when the washing sensor 21 tries to detect the end of rinsing, it detects a slight change in cloudiness. The end of rinsing must be determined, and the determination of the end of rinsing is extremely unreliable. On the other hand, in the rinsing sensor 22, even if a small amount of bubbles flows in, the light will be diffusely reflected, and the output of the turbidity detector 23 will change greatly, so the output at the start of rinsing (initial value) By detecting the difference between the output after a lapse of time, even a small amount of detergent remaining can be easily detected. Therefore, turbidity detection by the rinse sensor 22 is suitable for determining the completion of rinsing. FIGS. 5 and 6 show the other side of the foam trap, and FIG. By forming the tube downward, the flow resistance within the bubble trap 14 is increased, and by lowering the flow velocity, the bubble removal rate is increased. Further, in FIG. 6, the bottom wall of the foam trap 14 is sloped downward toward the outlet 16, thereby quickly draining the inside of the foam trap 14 and preventing water from remaining.

Although the above embodiment describes a fully automatic washing machine, the present invention can also be implemented in a two-tub type washing machine.

(Effects of the Invention) As described above, the present invention provides a highly reliable turbidity detection device that can accurately detect turbidity changes without being affected by bubbles and accurately determine the end of washing. can do.

[Brief explanation of the drawing]

Fig. 1 is a block diagram showing the control system of a fully automatic washing machine according to an embodiment of the present invention, Fig. 2 is an output characteristic diagram of the turbidity detection unit when the water permeability is detected by the same sensor as above, and Fig. 3 Figure 4 shows the output characteristics of the turbidity detection unit when turbidity is detected by the washing sensor during washing with washing water with high detergent concentration, and Figure 4 shows the turbidity when turbidity is detected by the rinsing sensor during the same washing. Output characteristics diagram of the degree detection section, 5th
3: Inner tank (washing tub), 14: Foam trap, 15: Inlet,
16: Outlet, 21: Washing sensor, 23: Turbidity detection section. Agent Patent attorney Aihiko Fuku (and 2 others) Figure 1 i, ? -ko← , ni, , tfflノ;1-
→4t mart) Figure 2 Figure 3 - B' product Figure 4 Between ends Figure 5 Figure 6

Claims (1)

[Claims] 1. In a washing machine that is equipped with a sensor that optically detects the turbidity of water and controls the washing operation based on the signal from this sensor, there is a circulation path through which water circulates in the washing tub, and a and a foam trap to be inserted, the foam trap has a passage cross-sectional area larger than the circulation path, and the inlet side is located above the outlet side, and the sensor is provided near the outlet of the foam trap. Turbidity detection device for washing machines.