JPS5812040B2 - Rinse detection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rinse detection device that can effectively detect the degree of contamination of rinse water of a washing machine.

Nowadays, automatic operation of washing machines is progressing, and detecting the degree of contamination of rinse water is an important issue for various issues such as water conservation.

The device for measuring the degree of contamination uses two pairs of light-emitting and receiving elements, one pair of light-emitting and receiving elements measures the light transmittance of a reference sample, and the other pair of light-emitting and receiving elements measures the light transmittance of the sample to be measured. There is a method using the so-called double beam method that measures the light transmittance of the beam.

However, this type of device requires a reference sample and requires complex arithmetic processing of the received light signal, making the device large and expensive.

Because of this, there are problems in applying it to washing machine automation.
Currently, the above automation is performed based on a predetermined time.

The present invention has been made in view of the above circumstances, and its purpose is to effectively detect the degree of contamination of washing rinse water with a simple configuration, and to be effective in automating washing machines. Another object of the present invention is to realize and provide a rinse detection device that can solve various problems such as water conservation.

Hereinafter, one embodiment of the apparatus of the present invention will be described with reference to the drawings.

Figure 1 is a basic configuration diagram, and 1 and 2 in the figure are light emitting diodes (hereinafter abbreviated as LEDs) as first and second light emitting elements. Phototransistor (hereinafter referred to as P
(abbreviated as TR) 3.4 are installed opposite each other.

The LED1 and PTR3 form a first light emitting/receiving element pair, and the LED2 and PTR4 form a second light emitting/receiving element pair.

These LEDs 1, 2 and PTRs 3, 4 are inserted into through holes drilled in the bases 5, 6, respectively, and fixed.

Transparent plates 7 and 8 are fixed to the light emitting and light receiving surfaces of these bases 5 and 6, respectively, and LEDs 1 and 2 and PTRs 3 and 4
The mounting is done to watertightly isolate the side from the optical path side.

Further, in the figure, reference numeral 9 denotes an optical waveguide interposed in the optical path on the opposite side of the first light emitting/receiving element, which guides the light emitted by the LED 1 without attenuating it.

Incidentally, although in reality there is always some attenuation of light intensity, the sample used for measurement, which becomes the optical path of the first and second light emitting/receiving element pair,
That is, by making the transmittance sufficiently small compared to the transmittance (attenuation amount) of the rinsing water, the light amount attenuation can be regarded as zero.

Further, washing and rinsing water is circulated between the two bases 5 and 6, and is used for detecting the degree of dirt.

Thus, the first light emitting/receiving element pair (LED1.PTR3)
The optical path length in the rinsing water is the distance LA from the end face of the optical waveguide 9 to the transparent plate 8.

Further, the optical path length in the rinsing water by the second light emitting/receiving element pair (LED2°PTR4) is the distance LB between the transparent plates 7.8.

The effects and effects of making the distance LA sufficiently shorter than LB will be described later.

FIG. 2 shows an embodiment in which the basic configuration shown in FIG. 1 is incorporated into a washing tub of a washing machine, and numeral 11 in the figure indicates the wall surface of the washing tub.

This device is attached by being inserted into a through hole bored in this wall surface 11.

That is, as described above, the electric circuit section on the side to which the LED and PTR are attached is watertightly isolated from the inside of the washing tub.

The means for this attachment is well known, such as using an O-ring, and the explanation thereof will be omitted here.

In Fig. 2, reference numeral 12 is a base, and the two through holes at each end of the base are equipped with LEDs as shown in Fig. 1 above.
1 and 2 and PTRs 3 and 4 are attached respectively.

These LEDs 1, 2 and PTR 3, 4 are mounted on the surface,
That is, optical waveguides 13, 14, 15, 16 made of, for example, acrylic material are fixed to the light emitting surface and the light receiving surface in a watertight manner, respectively.

The optical waveguide 13 fixed to the light emitting surface of the LED 1 is L
It has a 45° notch on the outside of the bent part.

The L-shaped arm portion 13a is arranged to face the optical waveguide 15 fixed to the light receiving surface of the PTR 3.

Further, optical waveguides 14 and 16 (located on the back side of optical waveguides 13 and 15 in FIG. 2) fixed to the light emitting and light receiving surfaces of the LED 2 and PTR 4, respectively, are also arranged oppositely.

Each of these optical waveguides 14, 15 and 16 has 41 notches cut out on the side opposite to the opposing surface of the end thereof.

And these optical waveguides 13, 14, 15, 16 are
The outer periphery of each of the fixing surfaces and the opposing surfaces between the optical waveguides is coated with aluminum plating or the like.

In this way, each of the 45° notched surfaces acts as a light reflecting surface, forming an optical path as shown by the dashed line in the figure.

The optical paths (optical waveguides 13, 1
4, 15, and 16) are immersed in the rinsing water poured into the same washing tub.

Thus, the optical path lengths LA, LB in the rinse water are set the same as shown in FIG.

Now, the electric circuit section of this device equipped with such an optical path is as follows.
For example, it is constructed as shown in FIG.

In FIG. 3, LEDs 1 and 2 and PTRs 3 and 4 are shown with the same reference numerals as in FIGS. 1 and 2.

The LEDs 1 and 2 have their anodes connected to a power supply +■ and their cathodes connected to transistors 21 and 22, so that the LEDs 1 and 2 are driven to emit light.

Note that 23 and 24 are emitter resistances of the transistors 21 and 22.

These transistors 21 and 22 are driven by an error amplifier 27 via base resistors 25 and 26, respectively.

This amplifier 27 connects the power supply +V to one input terminal through a resistor 28.
, 29 is input via an input resistor 30.

Further, the PTR 3 having a Darlington connection has a collector connected to the power supply +V and an emitter grounded via a trim resistor 31.

Then, the voltage generated in this trim resistor 31, that is, P
A voltage value corresponding to the light-receiving current flowing due to light reception by TR3 is inputted to the other input terminal of the error amplifier 27 via the input resistor 32.

That is, a portion of the photocoupler formed by the LED1 and PTR3 forms a feedback circuit for the error amplifier 27.

On the other hand, the LED driven by the transistor 22
The light emitted from No. 2 is received by PTR 4 having a Darlington configuration.

The collector of this PTR4 is connected to the power supply +V, and the emitter is grounded via the trim resistor 33.

A photometric signal (detection signal) is output from both ends of this trim resistor 33.

In other words, the PTR4 causes a current to flow through the trim resistor 33 according to the amount of light received from the LED2.

Therefore, a voltage corresponding to the amount of received light is generated across the resistor 33, and the same voltage is output as a detection signal.

Note that the lights emitted from the LEDs 1 and 2 are isolated from each other by the optical path shown in FIG. 2.

The device configured in this way operates as follows and exhibits various extraordinary advantages and effects.

First, the first pair of light-emitting and light-receiving elements, which serve as measurement standards, and the second pair of light-emitting and light-receiving elements, which are used for measurement, both have optical paths in the washing and rinsing water.

Therefore, the optical waveguides 13, 14, 15,
The 16 light-emitting and light-receiving surfaces are each immersed in washing and rinsing water under the same conditions.

Therefore, the degree of contamination caused by washing and rinsing water on the light-emitting and light-receiving surfaces is equal, and the influence of this on the measurement is canceled out.

This eliminates the unreasonableness of the conventional double beam method in which only the optical path on the side used for measurement is subject to changes in optical path characteristics due to contamination.

Next, the light used for measurement is monochromatic light, and the second
Let TS be the transmittance of the washing rinse water between the first light emitting light receiving element and the optical path length LB, then the transmittance TR of the washing rinse water between the first light emitting light receiving element and the optical path LA is expressed by Lambert Beer's law as follows.

TR=10 As shown in this equation, it is understood that in order to reduce the influence of the transmittance of washing and rinsing water used as a measurement standard, the ratio of LA and LB may be appropriately selected.

For example, if LA/LB=1/10, the transmittance is 10
+4% to -0 while changing from 0%T to 10%T
It can be measured theoretically within the measurement error range of %.

Further, by further increasing the above ratio, it is possible to reduce the error range to within +1%.

That is, in this device, even if the transmittance of the washing rinse water measured by the second pair of light-emitting and light-receiving elements fluctuates by about 10%T, the transmittance measured by the first pair of light-emitting and light-receiving elements is approximately 80%.
It is stable at about %T.

Therefore, this stable measurement value of about 80%T is used as the reference value.
In other words, by imaging the transmittance of 100% T and calculating the transmittance measured relative to the same reference value using the second light emitting/receiving element pair, it is possible to extremely effectively measure and detect the degree of contamination of washing rinse water. can.

Compensation for such transmittance and compensation for changes in characteristics due to dirt on the light-emitting and light-receiving surfaces described above are effectively performed by the circuit shown in FIG.

As explained above, the first light emitting/receiving element pair, that is, the LE
The optical circuit composed of Dl and PTR3 constitutes a feedback circuit of amplifier 27.

Therefore, when the light emitting/receiving surfaces of the optical waveguides 13, 14, 15, and 16 become dirty and the amount of light received decreases, the amount of light emitted from the LEDs 1 and 2 is increased by the action of the error amplifier 27.

Therefore, the decrease in the light emission intensity in the washing and rinsing underwater optical path due to the dirt on the light emitting and receiving surface is offset by the increase in the amount of light emitted from the LED 1.2, and a constant level of light is always incident on each of the light paths. become.

On the other hand, trim resistors 31 and 33 are connected to the emitters of PTRs 3 and 4, respectively, so that their detection levels can be variably set.

Therefore, for example, if the detection level is set to 100% T by variable setting of each trim resistor 31, 34 when water that has not yet been used for rinsing is injected as laundry rinsing water, the level detected thereafter corresponds to each of the above setting levels.

As described above, the amount of light emitted from the LEDs 1 and 2 is controlled so that the amount of light received by the PTR 3 is constant.

Therefore, the reference value is 100% T at both ends of the trim resistor 33.
The degree of contamination of the rinse water, that is, the transmittance, is measured and detected.

According to the experiments conducted by the inventors, when measuring LA with 5.5 mm and LS with 50 mm, the results shown in the following table were obtained.
It was confirmed that the error was +4.2% at most.

Furthermore, according to the drive circuit for LEDs 1 and 2 as described above, the LE
Regarding deterioration of characteristics over time of Dl,2, PTR3,4,
Since the amount of light emitted is controlled to be constant over a long period of time, there is no adverse effect.

Moreover, according to the structure shown in FIG. 1 or 2, the LE
Since Dl, 2 and PTRs 3, 4 are arranged in close proximity to each other, their operating environments are approximately the same, and therefore there is not much difference in characteristic changes.

Therefore, stable operation over a long period of time can be expected.

In addition, by providing the above measurement optical paths (LA, LB) in the washing tub, the degree of turbidity of the washing rinse water can be easily measured, thereby preventing wasteful rinsing operations in the washing tub and achieving effects such as water conservation. , very useful for washing machine automation.

As described in detail above, the device of the present invention uses the rinse water in the rinse water in the washing tub as a part of the optical path, and the first light emitting/receiving element pair and the first pair are optically opposed to each other. a second light emitting light receiving element pair having a rinse water path length longer than the rinsing water path length of the first light emitting light receiving element pair;
The amount of light emitted by the light emitting elements constituting the first pair of light emitting and receiving elements is controlled in order to always keep the output of the light receiving elements forming the first pair of light emitting and receiving elements proportional to the amount of light emitted by the light emitting elements. means for controlling the amount of light emitted by the light emitting elements constituting the second pair of light emitting light receiving elements; and means for outputting the light receiving element output of the second pair of light emitting light receiving elements as a contamination level signal of the rinse water. It is prepared.

Therefore, by arranging the first pair of light emitting and receiving elements and the control means in the above-described relationship, the light emitting and receiving surface of the second pair of light emitting and receiving elements, which is actually used directly for detecting the level of contamination, is contaminated with water stains and the like. Since the degree of contamination can be detected in a state where changes in characteristics due to temperature and changes in characteristics due to element deterioration are automatically compensated for in actual conditions, accurate detection can be performed over a long period of time.

Note that the present invention is not limited to the above embodiments.

For example, the means for using the amount of light received by the first light emitting/receiving element pair as a reference value can be modified in various ways.

Furthermore, it has been confirmed through experiments by the present inventors that if the ratio of the optical path length in the rinsing water is set to at least 1/3 or less, a sufficient effect can be achieved in detecting the degree of dirt in the washing rinsing water.

However, when the above optical path length ratio is reduced to 1/3, approximately 1
It is necessary to take into account that an error of 0% occurs, and in the case of 115, an error of approximately 8% is involved.

Further, an optical fiber or the like may be used as the optical waveguide, and various types of light sources and light receivers may be used.

In short, the present invention can be implemented with various modifications without departing from the gist thereof.

[Brief explanation of the drawing]

FIG. 1 is a basic configuration diagram of the device of the present invention, FIG. 2 is a schematic configuration diagram showing an embodiment of the invention, and FIG. 3 is a diagram of the electrical circuit configuration of the device of the same embodiment. 1.2... Light emitter (LED), 3,4... Light receiver (
PTR), 5, 6, 12... Base, 9, 13° 14.
15, 16... Optical waveguide, 21, 22... Drive transistor, 27... Error amplifier, 31, 33... Trim resistor (for correction).

Claims (1)

[Claims] 1. First washers provided optically opposite each other in the rinse water in the washing tub using the rinse water as part of the optical path.
The second rinsing water source path length is set to be longer than the rinsing water source path length of the light emitting light receiving element pair and the first light emitting light receiving element pair.
The amount of light emitted by the light emitting elements constituting the first pair of light emitting light receiving elements is controlled in order to always keep constant the output of the pair of light emitting light receiving elements and the light receiving elements constituting the first pair of light emitting light receiving elements. means for controlling the amount of light emitted by the light emitting elements constituting the second pair of light emitting and light receiving elements in proportion to the amount of light emitting from the light emitting elements; A rinsing detection device characterized by comprising: means for outputting as a signal.