JPH0323187Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Technical Field> The present invention relates to a liquid level detection device, such as a water level detection device, in a washing machine or the like.

<Prior Art> In general, washing clothes with an amount of water commensurate with the load on the clothes not only improves the washing effect but also prevents wastage of detergent and water.

Conventionally, various structures have been used as liquid level detection devices to automatically control the water level in washing machines, but if the buoyancy of a float caused by water is used, it requires a large number of parts and is expensive. However, the assembly work was troublesome, and the water level could not be detected accurately if a pressure switch was used.

<Purpose> The object of the present invention is to provide a liquid level detection device that can be manufactured at low cost with a small number of parts, can simplify assembly work, and can accurately detect the liquid level.

<Example> Hereinafter, an example of the present invention will be described based on FIGS. 1 and 2. FIG. 1 is a schematic longitudinal sectional view of a washing machine equipped with the liquid level detection device of the present invention, and FIG. 2 is an electric circuit diagram of the liquid level detection device. As shown in the figure, the liquid level detection device in the washing machine is A plurality of light guide members 1A, 1B each having the same diameter and made of approximately U-shaped transparent material such as glass, acrylic resin, flexible glass fiber, etc.
1C, a light emitting element 2 such as a lamp or LED arranged on one end side of the light guide members 1A, 1B, and 1C, and a phototransistor (or photodiode, etc.) arranged on the other end side of the light guide member 1. The light receiving element 3 includes a light receiving element 3 and a detection circuit 4 that detects an increase or decrease in the amount of light received by the light receiving element 3. The plurality of substantially U-shaped light guide members 1A, 1B, and 1C each having the same diameter have cutout portions 1a, 1b, and 1c at the lower ends thereof for liquid level detection and liquid transparency (rinsing degree) detection, respectively.
1b, 1c are formed, and each of the light guide members 1A, 1
The notches 1a, 1b, and 1c of B and 1C are located at different vertical positions, that is, the lower liquid level W1 and the middle liquid level W
2. The upper liquid level is set to W3, and the light from the light emitting element 2 passes through the inside of the light guide members 1A, 1B, 1C and the lower end notches 1a, 1b, 1c and reaches the light receiving element 3, A detection circuit 4 detects a change in the amount of light when the lower end notches 1a, 1b, 1c of the light guide members 1A, 1B, 1C are submerged in liquid.

In addition, 1D is a connecting member for positioning the light outlet 1E and the light inlet 1F of the cutout portions of the light guide members 1A, 1B, and 1C, 5 is the water tank of the washing machine, 6 is the pulsator at the bottom, P1 and P2 are the water supply pipes, P3 is the drain pipe, SV1
~SV7 is a solenoid valve, IC is an A/D converter that digitally converts the output of the light receiving element 3, 8 is an operational amplifier for amplifying the output of the converter 7, and 7 is a microcomputer-made control circuit that receives the output of the operational amplifier IC. The solenoid valves SV1 to SV7 are controlled by this output.

Next, to explain the operation, the light emitted from the light emitting element 2 is divided equally into three light guide members 1A, 1B,
1C and exits from the exit 1E on the light emitting element 2 side of the light guiding members 1A, 1B, 1C through the notch 1.
a, 1b, 1c and light guide members 1A, 1B,
The light enters the entrance 1F on the side of the light-receiving element 3 of 1C, but depending on the refractive index of the water, the light enters the light-guiding member 1A, 1B, 1C on the light-receiving element side depending on the presence or absence of water in the notches 1a, 1b, 1c. The amount of light is different. Therefore, the output of the light receiving element 3 is different.

Since the notches 1a, 1b, and 1c are configured so that the light reception is maximum when the washing tub is filled with water, the light amount and current value output 0, 1, 2, 3 are obtained.

When the water level W1 selection button (not shown) on the operation panel 9 is turned on, the water supply solenoid valve SV7 is turned on, water is supplied, and the solenoid valve SV5 is closed, and the solenoid valve SV1 is turned on.
When it opens and water reaches the notch 1a, the water supply stops. Similarly, when the water level W2 selection button (not shown) is turned on, the solenoid valve SV1 closes, the water supply solenoid valve SV7 opens and water is supplied, and the solenoid valve SV2 also opens.
When the water level reaches the notch 1b, the water supply stops. Further, the relationship between the water level W3, the lower end notch 1c, and the solenoid valve SV3 is also the same as above.

Also, when specifying a low water level from a high water level, the solenoid valve
When SV6 opens, it moves to a specified position (for example, water level W2).
position)) until the lower end notch 1b senses the solenoid valve.
SV6 and SV2 open.

In the rinsing process of a washing machine, water is generally supplied to a set water level, and then the washing machine is agitated to separate dirt and detergent from the laundry and drain the washing machine. and,
Water is supplied again and the above operation is repeated. At this time, since cloudy rinsing liquid is present in at least one of the lower end notches 1a, 1b, and 1c, the rinsing state can be detected by utilizing the fact that the light to the light receiving element 3 is scattered and absorbed and reduced. Do this.

In this process, first, the solenoid valves SV4, SV1,
SV2 and SV3 open, and fresh water flows into the notches 1a, 1b,
The notches 1a and 1 are sprayed into the notches 1a and 1c to remove dirt attached during the washing process and create a clean water environment.
To make it easy to detect the rinsing state at at least one of b and 1c.

By stirring, the rinsing liquid becomes cloudy, and the degree of turbidity is detected to detect the rinsing state.

With the above structure, the rinsing condition can be detected correctly regardless of the water level.

Although a plurality of light guiding members were used in the above embodiment, in the present invention, one light guiding member may be used to detect the water level and the degree of rinsing (transparency) at one location.

<Effects> As is clear from the above description, the present invention includes a plurality of substantially U-shaped light guiding members whose ends are bundled in an aquarium and whose lower ends are arranged at different height positions with different vertical positions; A light emitting element arranged at one end of the light guide member, a light receiving element arranged at the other end of the light guide member, and a lower end for liquid level detection and liquid transparency detection formed at the lower end of each light guide member. a notch, and a detection circuit that detects an increase or decrease in the amount of light received by the light receiving element when light from the light emitting element passes through the interior of the light guide member and the lower end notch and reaches the light receiving element, the detection circuit has a water level detection function that detects the water level based on the amount of transmitted light that changes depending on the difference in refractive index when water enters the notch and when water is present and when there is no water. It has a rinsing state detection function that detects the transparency of water based on the amount of transmitted light that changes as it is scattered and absorbed.

Therefore, according to the present invention, by using a light emitting/receiving element and a plurality of light guiding members, and by bringing the lower end notch of the light guiding member into direct contact with water, the conventionally used float can be omitted and the detection can be carried out. Since the number of parts of the device is small, it can be made at low cost, and the assembly work can be simplified. Moreover, since it uses light, there is no need for electrical wiring inside the tank, and there is no possibility of malfunction due to poor insulation, etc., so the water level can be detected accurately.

Furthermore, during the rinsing process, the transparency of the rinsing liquid is detected based on the amount of transmitted light that changes as light is scattered and absorbed depending on the degree of turbidity of the water, so the rinsing state can be accurately detected.

Furthermore, by using the liquid level detection device of the present invention, it is possible to specify the load amount and automatically specify the water level, and when stubborn washing is required,
It is also possible to increase the washing effect by lowering the water level and using the mechanical power of the stirring blades as the main source.

On the other hand, when loosening water, the higher the amount of water, the better the loosening effect during rinsing. Therefore, by changing the combination of water amount and rotational strength (rotation time) of the stirring blade, it is possible to It is possible to provide a washing machine that enhances the loosening effect during suitable washing and rinsing.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical sectional view of a washing machine equipped with a liquid level detection device according to an embodiment of the present invention, and FIG. 2 is an electric circuit diagram of the same liquid level detection device. 1A, 1B, 1C...light guide member, 1a, 1b,
1c...Notch, 2...Light emitting element, 3...Light receiving element, 4...Detection circuit, W1...Lower liquid level, W2...
Middle liquid level, W3...upper liquid level.

Claims (1)

[Scope of Claim for Utility Model Registration] A plurality of substantially U-shaped light guiding members whose both ends are bundled in a water tank and whose lower ends are arranged at different height positions in vertical positions, and one end of the light guiding members. a light emitting element arranged on the light guide member, a light receiving element arranged on the other end side of the light guide member, a lower end cutout for liquid level detection and liquid transparency detection formed at the lower end of each light guide member, and the light emitting element. a detection circuit that detects an increase or decrease in the amount of light received by the light receiving element when light from the element passes through the inside of the light guide member and the lower end notch and reaches the light receiving element, and the detection circuit is configured to A water level detection function detects the water level based on the amount of light transmitted, which changes due to the difference in refractive index between when water enters and when there is no water, and when rinsing, light is scattered and absorbed depending on the degree of turbidity of the water. 1. A liquid level detection device for a washing machine, etc., characterized by having a rinsing state detection function for detecting the transparency of water based on the amount of transmitted light.