JPH0252698A - Method for detecting drain for equipment - Google Patents

Abstract

PURPOSE:To eliminate an influence due to the change of a temperature and to the dispersion of a water level detecting means by providing a delay time for a definite time and executing a drain completion when a time since the drain is started until the change of the output signal of the water level detecting means for each definite time is made into a definite value or below is equal to the definite time or above. CONSTITUTION:First, a drain valve is turned on, the drain is started, the delay for a definite time Td is provided, and thereafter, a frequency is measured (f0). The delay for the definite time is provided, the frequency is measured again, and the value is made into fN. At the time of fN-f0<=fP, the fact that the water level change is eliminated is decided, and an advance to a step 407 is executed. Further, when the frequency at such a time is a minimum value fa or above of the dispersion of the vibrating frequency at the time of the pressure 0 of the water level detecting means, the fact that the water level in a tank approaches a water level reference surface is decided, and further, when the time until the water level change is eliminated is twenty min or above at a step 410, the delay for the definite time is provided, thereafter, the drain is completed at a step 408, and the drain valve is turned off.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention is applicable to equipment that involves drainage operation, such as electric washing machines.
The present invention relates to a drainage detection method for a device that detects the completion of drainage.

BACKGROUND OF THE INVENTION In recent years, water level detection means have increasingly been used to detect the end of drainage in equipment.

Therefore, a conventional method for detecting the end of drainage using a water level detection means will be explained with reference to FIGS. 4, 8, 9, and 1o. Fig. 4 is a block diagram of the main parts of a fully automatic washing machine, Fig. 8 is a sectional view of the fully automatic washing machine, Fig. 9 is a flowchart showing a conventional drain completion detection method,
) is a characteristic diagram showing the change over time of the output signal of the water level detection means during drainage.

First, a general water level detection means will be explained with reference to FIGS. 5, 6, and 7.

Figure 5 is a cross-sectional view of the displacement detection unit that converts a change in pressure proportional to the water level into a change in coil inductance, and Figure 6 is an electric circuit of an oscillation circuit that converts a change in coil inductance into a change in frequency. It is a diagram. In FIG. 6, P is a pressure proportional to the water level, 15 is a thin film diaphragm made of rubber, etc., 16 is a coil, 17 is fixed to the diaphragm 15, and the inside of the coil 16 is moved in the vertical direction in FIG. A movable magnetic body, 18 a spring for suppressing displacement of the magnetic body 17, 19 an adjustment screw, and 2o an outer frame for fixing the circumferential portion of the diaphragm 15, the coil 16, and the adjustment screw 19. The coil 16 is a part of the oscillation circuit shown in FIG. In FIG. 6, 21 is an inverter, 22 is a feedback resistor, and 23 and 24 are capacitors.

With the above configuration, when the pressure P proportional to the water level applied to the diaphragm 15 changes, the magnetic body 1 is displaced in the vertical direction under the action of the spring 18. At this time, since the magnetic body 17 moves within the coil 1e, the inductance of the coil 16 changes. When this inductance changes, the frequency of the oscillation circuit shown in FIG. 6 changes. Ideally, the relationship between water level and frequency at this time would be a straight line as shown in 8 in Figure 7, but due to variations in the free length of the spring 18, variations in the adjustment of the adjustment screw 19, etc. 7th
As shown in b in the figure, there may be a characteristic where there is a region where the frequency does not change at all in the vicinity of minute pressure;
As shown in C in the figure, there are three possible cases: a sudden change in frequency occurs in the vicinity of minute pressure, and then a gradual change.

Next, in Fig. 4, 1 is an input means for setting the water level, washing time, number of rinses, spin-drying time, etc., and 2 is an input means for setting the water level, washing time, number of rinses, spin-drying time, etc., and 2 is an input means for setting the water level, washing time, number of rinses, spin-drying time, etc. Display means for informing the user of the progress status, etc., 3
6 and 6 are bidirectional thyristors for driving the washing/drying motor 13; 7 is a bidirectional thyristor for driving the water supply valve 12; and 8 is a bidirectional thyristor for driving the drain valve 11. A bidirectional thyristor is a drain valve driving means, 9 is a commercial power supply, 1o is a power switch, 14 is a phase advancing capacitor, and 4 is a control means for inputting the output frequency signal of the water level detection means 3 to control the entire device. It is. Furthermore, in FIG. 8, 25 is an outer frame, 26 is a water receptacle, 27 is a washing and dewatering tank, and 28 is a rotary blade 29 during washing.
This is a power switching mechanism for switching the power of the washing/extracting motor 13 so as to rotate the washing/extracting tank 27 during dehydration.

3o is an air pocket for generating pressure corresponding to the water level, 31 is an air hose for transmitting the pressure generated in the air pocket 3o to the water level detection means 3, and 32 is a drainage hose.

In the above configuration, when draining, the output frequency of the water level detection means 3 increases as the water level decreases, and when the water level in the tank 26 approaches the water level reference plane in the water receiver shown in FIG. becomes constant. Therefore, the change over time in the output frequency of the water level detection means 3 during drainage is as shown in Fig. 1Q. Here, the conventional method for detecting the end of drainage will be explained using the flowchart shown in FIG.
At 0, the bidirectional thyristor 8, which is the drain valve driving means, is turned on.
Then, the drain valve 11'1ONj is activated to start draining. At this time, the frequency increases, although it is instantaneous. This is because negative pressure is applied within the air pocket 30 at the moment the drain valve 11 is turned on in FIG. To be careful, a certain time delay is provided in step 401 to ignore this negative pressure, and then the frequency f is set in step 402. Measure. Then, in step 403, a certain time delay is provided, and in step 404, the output frequency of the water level detection means 3 is measured again, and this value is f)
shall be. In step 405, f, -fo is compared with f,k, and if f, -f0≦f, the water receiver determines that the water level change in the tank 26 is almost constant, and the process proceeds to step 407. Here, f is a constant. In step 407, if the frequency at that time is 14 or more, that is, if the water level in the tank 26 is below the water level corresponding to 8, the water receiver determines that drainage has ended, and in step 408, the drain valve is turned off.

It should be noted that is the minimum value when considering the variation in the frequency of the water level detecting means 3 when the water level is 0. If f, < f in step 407, it is determined that there is some kind of abnormality, and the abnormality is notified in step 409. Also, in step 405, f, -f. >f.

If so, the control method is to determine that the water level is fluctuating, set fN to f0 in step 406, and return to step 403.

Problems to be Solved by the Invention In such a conventional configuration, the diaphragm 15, coil 16,
If the characteristics of the magnetic body 17, spring 18, and capacitors 23 and 24 vary, the relationship between the water level and frequency will vary within the characteristic ranges indicated by C and C in Figure 7, and no change in frequency will be detected. In the case of characteristic b, water remains in the dewatering step and the dewatering process is started, resulting in poor starting characteristics of the washing and dewatering motor 13 during dewatering.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems, and provides a method for detecting drainage of equipment, which causes drainage to end when the water level is below the water level reference level, regardless of changes in the ambient temperature used or variations in the water level detection means. The purpose of this invention is to provide a method for detecting waste water that can immediately proceed to the next step if there is no water in the washing tub from the beginning.

Means for Solving the Problem In order to achieve this object, the drainage detection method of the device of the present invention is based on the method of detecting drainage of water from the time when the water level is completely discharged until the change in the output signal of the water level detection means at a certain period of time becomes below a certain value. If the time is longer than a certain period of time, a certain period of delay time is provided and drainage is completed.

Operation According to the above method, if the time until the change in the output frequency of the water level detection means becomes less than a certain value is less than a certain period of time, it is determined that there is no water in the washing tub and the draining is immediately terminated. Proceed to the next process. Also, if the time it takes for the change in the output frequency to become below a certain value for a certain period of time or more, it is determined that there was water in the washing tub initially, and after a certain delay time, the draining is completed. This is what I did. Therefore, if there is no water at the beginning, the drainage will end immediately, and if there is water at the beginning, the drainage will end when the water level is below the reference level.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Below is a drawing of an embodiment of the present invention. I will explain while referring to it.

FIG. 1 is a flowchart for explaining the actual drainage operation, and the same step numbers as in FIG. 9 indicate the same functions. Figure 2 is a characteristic diagram showing summerization over time after the start of drainage. FIG. 3 shows water level data when it is determined that drainage has ended in response to variations in the water level detection means in this embodiment. Further, the configuration of the fully automatic washing machine is as shown in FIGS. 4 and 8, and the configuration and characteristics of the water level detection means are shown in FIGS. 5, 6, and 7, which are similar to the conventional example. The configuration is the same as that of

In the above configuration, the drainage operation of this embodiment will be explained using the flowchart t'' in FIG. 1. First, step 400
Turn the drain valve 1ONl and start draining.

At this time, as shown in FIG. 2, if the time when drainage starts is set to 0, the frequency becomes abnormally high after a short delay. This is because negative pressure is applied to the air pocket 3o at the moment the drain valve 11 turns ON in FIG. Next, in step 401, in order to ignore the frequency caused by this negative pressure, a delay of a certain time T (1) is set.
2. Measure the frequency. This frequency is 10 in Figure 2.
It is. A certain time delay is provided in step 403, and the frequency is measured again in step 404, and this value is set as 'if'. Stella 7'' 405 compares f, -fo with constants f, k, and if f, -f0≦f, it is determined that the water level has stopped changing, and the process proceeds to step 407, where the frequency at that time is determined by the water level detection means 3. If it is equal to or greater than the minimum value of the variation in oscillation frequency when the pressure is 0, it is determined that the water level in the tank has approached the water level reference plane, and furthermore, if the time until the water level stops changing in step 410 is 20 seconds or more, After providing a certain time delay in step 411, step 408
When draining is finished, turn off the drain valve. This step 4
By delaying for a certain period of time in step 11, even in the case of the characteristics of the water level detecting means 3 shown in FIG. Next, in step 407, if f<fa, the drain hose 32
The water receiver determines that there is water remaining in the tank 26 due to the fact that the drain valve 11 is in an upright position or an abnormality has occurred in the drain valve 11, and in step 409, a drain abnormality display is notified.

If it is determined in step 410 that the time until the water level stops changing is less than 20 seconds, the process immediately proceeds to step 408. See you at step 406! , -f0>f, then
The water receiver determines that the water level in the tank 26 is fluctuating, and sends the data to f in step 406. Step 4
Return to 03. To explain this series of operations using the characteristic diagram in Fig. 2, from time t knee to t yaw, the output frequency of the water level detection means 3 changes from fm-5 to fm-2, so the water is drained. I'm on my way. The same applies to tl-2 to 1m-.

Between tm-3 and tm, the water level in the tank 26 of the water receiver is near the water level reference plane, and the frequency after that is constant at f, and if fm-fm-1≦f, then at the time tln. Then, after a further delay of a certain period of time, it is determined that the drainage has ended, and f, −f
, -, > f, it is determined that the drainage is completed after a further delay of a certain time from the time tlQ+1.

FIG. 3 shows the delay in step 41o in the drain detection method explained in the conventional example and in the embodiment of the present invention with respect to pressure variations when the frequency starts to change in the vicinity of minute pressure of the water level detection means 3. What is the water level height data from the water level reference surface when the time is 10 seconds? show. As is clear from this data, by providing a further delay time of a certain amount of time after the frequency change at each certain period of time becomes less than a certain value, it is possible to reliably determine the end of drainage when the water level is below the reference level. be.

Although this embodiment has been described with respect to the draining operation of a fully automatic washing machine, it can also be applied to equipment that involves a draining operation, such as an electric dishwasher. Furthermore, although a frequency signal was used as the output signal of the water level detection means, this may also be a water level detection means whose voltage changes according to changes in the water level, and furthermore, the value of the water level detection signal decreases as the water level increases. Although I have explained this for objects, the same effect also applies to objects that grow larger as the water level increases.

Effects of the Invention As is clear from the above embodiments, the drainage detection method of the device of the present invention is based on the method of detecting drainage using a device according to the present invention. If is longer than a certain time, set a delay time of -a certain time,
Since it is determined that the drainage is completed, it can be determined that the drainage is completed when the water level becomes below the water level reference level, regardless of variations in the characteristics of the water level detecting means in the vicinity of minute pressure.

In addition, if the time required for the change in the output signal of the water level detection means to become below a certain value for less than a certain period of time, it is determined that there is no water from the beginning, and the drainage is immediately finished and the next process is started. This will save you time when proceeding.

[Brief explanation of the drawing]

Fig. 1 is a flowchart showing the processing method of the control means during drainage in an embodiment of the present invention, Fig. 2 is a characteristic diagram showing the temporal change in the output frequency of the water level detection means after the start of drainage,
The figure shows the height of the water level from the water level reference plane when detecting drainage according to the present invention and the conventional method, Fig. 4 is a block diagram of a fully automatic washing machine, and Fig. 5 (2) is a sectional view of the water level detection means. Figure 6 is an electrical circuit diagram of the oscillation circuit, Figure 7 is its characteristic diagram, Figure 8 is a sectional view of a fully automatic washing machine, Figure 9 is a flowchart explaining the entire conventional waste water treatment method, and the 1Q The figure is a characteristic diagram showing changes over time in the output frequency of the water level detection means for explaining the conventional drainage method. 3... Water level detection means, 4... Control means, 8... Drain valve driving means. Name of agent: Patent attorney Shigetaka Awano and one other person Figure 4 Figure 1 Figure 1 Figure 10 Figure 10

Claims (1)

[Claims] A drain valve driving means for controlling ON/OFF of a drain valve for draining water in the tank, a water level detecting means for detecting the water level in the tank and converting it into an electric signal, and an output signal of the water level detecting means. control means for controlling the drain valve drive means, the control means controlling the time from the start of draining until the change in the output signal of the water level detection means at fixed time intervals becomes equal to or less than a fixed value. A drainage detection method for equipment that sets a delay time of a certain time to complete drainage if it is longer than a certain period of time.