JP2523812B2 - Dishwasher water level detector - Google Patents

Description

TECHNICAL FIELD The present invention relates to a water level detection device for a dishwasher.

2. Description of the Related Art Conventionally, a water level detecting device for a dishwasher has a structure as shown in FIG. In the figure, 30 is a float, 31 is a microswitch, 32 is a water supply valve for supplying water to the tank A, 33 is a washing pump motor, and 34 is a control device of the dishwasher. The operation will be described with this configuration. First, the control device of the dishwasher.
The water supply valve 32 is opened by the output of 34, and water is accumulated in the tank A. Then the float 30 floats and the micro switch
Press switch 31. The signal is the dishwasher controller
It was sent to 34, the water supply valve 32 was closed by the output of the control device 34, and the water level of the dishwasher was kept constant.

However, in the above configuration, the water supply amount is determined only by the positional relationship between the float 30 and the micro switch 31. That is, there is a problem to be solved in that the water supply amount may increase or decrease due to variations in the mounting position of the micro switch 31 and variations in the floating position of the float. For example, when the amount of water supply is small as the load of the washing pump, the injection pressure from the washing nozzle becomes small, and the dishes cannot be washed, and when the amount is large, water resources and electric power are wasted.

SUMMARY OF THE INVENTION The first object of the present invention is to solve the above-mentioned conventional problems, and it is a first object of the present invention to supply an optimum amount of water supply as a load of a cleaning pump.

The second purpose is to prevent the water from overflowing from the dishwasher even when the water level detection device fails.

A third object is to continue water supply without closing the water supply valve even when the water level detection device malfunctions instantaneously during water supply.

A fourth object is to detect that the dishwasher has been operated with the main tap of the water supply directly connected to the water supply valve of the dishwasher being closed, and to notify the abnormality.

A fifth object is to detect the proper water level, close the water supply valve, detect the presence or absence of water leakage during the cleaning process, and notify the abnormality if there is water leakage.

The seventh purpose is to detect that drainage is not possible even if drainage is performed because the drainage port is clogged.

Means for Solving the Problems The first means for achieving the first object of the present invention is:
A cleaning pump that circulates the cleaning water in the cleaning tank, a cleaning nozzle that sprays the cleaning water, a cleaning pump motor that drives the cleaning pump, a motor load fluctuation detection unit that detects load fluctuations of the cleaning pump motor, and its output. The gradient detecting means for detecting the gradient of the, the gradient determining means for detecting that the predetermined gradient has been reached, the water level determining means for determining whether the water level of the dishwasher is suitable or not, and the water supply valve. With a water supply valve driving means for opening and closing, the cleaning pump motor is driven and water is supplied from the start of water supply in the cleaning process or the rinsing process, and the slope determination means has reached a predetermined slope determined from the signal of the slope detection means. When this is detected, the water level determination means determines that the water level is appropriate and stops water supply.

A second means of the present invention comprises a first timing means for setting the time from the start of water supply until the water level of the dishwasher reaches the maximum water level as a first predetermined time, and further comprising first timing means for starting timing from the start of water supply, When the water level determination means does not determine that the water level is appropriate by the time the first timing means measures the first predetermined time, the water supply is stopped when the first timing means measures the first predetermined time. Is.

A third means of the present invention is, in addition to the first means, provided with a second timing means for setting a time from the start of water supply to the start of gradient determination to be a second predetermined time, and for starting a timing from the start of water supply. Water is forcibly supplied from the start until the second time measuring means measures the second predetermined time.

In addition to the third means, the fourth means of the present invention is provided with a third timing means for setting the time to reach the maximum gradient from the start of the water supply to the third predetermined time and for starting the timing from the start of the water supply, If the slope detecting means does not detect the slope from the start of the water supply until the second time measuring means measures the second predetermined time, the water supply failure is notified.

In addition to the first means, the fifth means of the present invention operates the slope detecting means for a predetermined time after the water supply is stopped to continue the slope detection,
When a change in the gradient is detected, the water leak is notified.

Action The action of the first means will be described. First, open the water supply valve,
Then, the washing pump is operated. In other words, use the washing pump from the water supply process. Therefore, the timing for closing the water supply valve is determined by detecting a stable gradient of the load fluctuation output of the washing pump motor by using the noise removing means, and determining it by the gradient determining means.

The second means causes the first timing means to measure the time when the water supply starts, and when the first predetermined time set in the first timing means elapses, the water is forcibly supplied regardless of the signal from the water level determination means. Close the valve.

The third means is the water supply valve opening means from the start of water supply to the second predetermined time set in the second timing means,
The water supply valve is forcibly opened regardless of the output of the water level determination means.

The fourth means is a water supply failure when the water supply failure notification means detects that the output value of the slope detection means does not change from the start of water supply to the third predetermined time set in the third timing means. Notify that there is.

The fifth means detects the proper water level, closes the water supply valve, and enters the washing process, and when the water leak detecting means detects that the value of the gradient detecting means exceeds a certain value during the washing step. Notify that the water is leaking.

Embodiments Embodiments of the present invention will be described below with reference to the drawings.

1 to 6 show a first embodiment of the present invention. FIG. 1 is a block diagram showing the overall configuration.
Fig. 3 is a characteristic diagram showing the load fluctuation characteristics of the washing pump, Fig. 3 is a block diagram showing the structure of the water level detection device, Fig. 4 is the same circuit diagram, and Fig. 5 is the main part of the circuit diagram shown in Fig. 4. FIG. 6 is a voltage waveform diagram showing the voltage waveform of the part, and FIG. 6 is a characteristic diagram showing the noise removal characteristics of the noise removal means that constitutes the water level detection device.

In FIG. 1, reference numeral 1 is a water level detecting device, the output of which is connected to a water supply valve 4. 2 is a control device for the dishwasher, 3 is a washing pump, and 4 is a water supply valve which is opened and closed by the output of the control device 2 or the water level detection device 1. An example in which the characteristics of the cleaning pump 3 are measured by using the water level detecting device 1 is the cleaning pump load fluctuation characteristic shown in FIG. In the figure, “a” shows the fluctuation of the terminal voltage of the capacitor constituting the cleaning pump motor, “b” shows the fluctuation of the current value of the cleaning pump motor, and “c” shows the fluctuation of the discharge pressure. Figure 3 shows
It is a block diagram which shows the structure of the water level detection apparatus 1 of FIG. In FIG. 3, 5 is a motor load fluctuation detecting means for measuring / detecting a motor load fluctuation of the washing pump 3, 6 is an amplifying means for amplifying an output signal of the motor load fluctuation detecting means, and 7 is an output of the amplifying means 6. Noise removing means for removing a noise component from the output, 8 is a gradient detecting means for differentiating the output of the noise removing means 7 with respect to time to detect a gradient, and 9 is an output of the gradient detecting means 8 reaches a specific value to obtain a specific gradient. Is a water level determination means for determining whether or not the water level of the dishwasher is appropriate or inadequate based on the inclination determination means 9, and 11 is a water supply valve driving means for opening and closing the water supply valve. FIG. 4 is a circuit diagram showing a specific circuit of the block diagram of the water level detection device 1 shown in FIG. In FIG. 4, reference numeral 5 is a motor load fluctuation detecting means, which is a coil of the cleaning pump motor 3.
3a, capacitor 3b, rectifying block 5a, resistors 5b, 5c, diode 5d, capacitor 5e, resistors 5f, 5g. A
Is the output end of this load fluctuation detecting means. Capacitor 3b
Is rectified by the rectification block 5a, divided by the resistors 5b and 5c, and converted into direct current by the diode 5d, the capacitor 5e, and the resistors 5f and 5g. 5 is an amplifying means, and an operational amplifier 6
It is composed of a, 6b and 6c and resistors 6d to 6i. Here, the operational amplifiers 6a and 6b operate as a buffer, and the operational amplifier 6c and the resistors 6f to 6i form a differential amplifier. The output of the motor load fluctuation detecting means 5 is inputted from the point A to the plus side of the operational amplifier 6a, and the positive input terminal of the operational amplifier 6b is inputted with the constant voltage divided by the resistors 6d and 6e by the DC constant voltage source 6j. . These two voltages are input to the operational amplifier 6c that constitutes a differential amplifier via resistors 6f and 6h, inverted and amplified, and output to the point B. Reference numeral 7 is a noise removing means for removing a noise component from the output signal of the amplifying means 6, and is composed of resistors 7a to 7f, capacitors 7g to 7j, and operational amplifiers 7b and 7e.
The resistors 7a, 7b, 7c, the capacitors 7g, 7h, and the operational amplifier 7k act as a known active filter.
The resistors 7d, 7e, 7f, the capacitors 7i, 7j, and the operational amplifier 7l also function as well-known active filters.
In the present embodiment, the noise removing means 7 is configured with the two-stage active filter as described above, but it is not always necessary to pay attention to the number of stages. The output of the amplifying means 6 is an operational amplifier which constitutes the first active filter from the point B.
It is input to 7k via resistors 7a and 7b, and noise components are removed. Further, this output is similarly inputted to the operational amplifier 7l which constitutes the second active filter through the resistors 7d and 7e, and the noise component is further removed here. The signal from which the noise is removed is output to C.
Reference numeral 8 is a gradient detecting means for detecting the gradient of the signal of the noise removing means, and includes a capacitor 8a, resistors 8b to 8d, an operational amplifier.
It is composed of 8e. The capacitor 8a and the resistor 8b constitute a known differential circuit, and the operational amplifier 8e and the resistors 8c and 8d constitute a known normal amplification circuit. The output signal of the noise removing means is input from C to the capacitor 8a forming this differentiating circuit, differentiated, input to the plus side of the operational amplifier 8e of the non-inverting amplifier circuit, amplified, and output to the point D. Reference numeral 9 is a gradient judging means for judging whether or not the gradient of the output of the gradient detecting means reaches a specific value, which is composed of resistors 9a to 9c and an operational amplifier 9d. The operational amplifier 9d compares the output of the gradient detecting means 8 and the voltage of the DC constant voltage source 6j with the voltage divided by the resistors 9a and 9b, and generates an H output signal when the output of the gradient detecting means 8 is larger. However, when it is small, it becomes L. Point E indicates its output end. Reference numeral 10 is a water level determining means for determining whether the output of the gradient detecting means 8 detected by the gradient determining means 9 is an uphill gradient or a downhill gradient. Ten
For example, a is a timer that sets a minimum time at which the water level is considered to reach an appropriate level from the moment the water is started to be supplied to the tank A, that is, the moment the motor 3 is turned on, and starts timekeeping. Reference numeral 5i is a signal source for supplying a timing start signal of the timer 10a, which shares the point 5i divided by the resistors 5g and 5h of the motor load variation detecting means 5. This gradient selection means
The output of 10 is the feed valve drive means connected to the next stage at point F
Connected to 11. The water supply valve driving means 11 for driving the water supply valve 4 is composed of a resistor 11a, a transistor 11b, a resistor 11d, a transistor 11c, and a water supply valve coil 4a. The water supply valve coil 4a includes two transistors 11b from the DC constant voltage source 6j,
While one of 11d is turned on, an electric current flows and the water supply valve is opened to supply water to the tank A. G is an output end of the water supply valve driving means 11 and also an output end of the water level detection device 1 as a whole.

FIG. 5 shows voltage waveforms at the respective output terminals A to G of the water level detecting device 1.

A, B, C, D, E, F, and G in FIG. 5 correspond to the output terminals A to G of each part of the water level detection device shown in FIG. 4, respectively. In FIG. 5, t ₁ and t ₂ shown on the time axis are the time when the washing pump motor 3 is turned on, the time when the water supply valve 4 is opened, t ₃ is the time when the washing pump motor 3 is turned off, and t ₄ is the water level detection device 1 It is a time indicating the moment when the whole is activated. t ₅ is the moment when the output of the gradient detecting means 8 detected by the gradient determining means 9 is an upward gradient. A in the figure is an output waveform of the motor load detection means 5,
During the period from t ₁ to t ₂ , the motor 3 is operating, but the water supply is not yet started. From t ₂ to t _4, the water supply valve 4 is opened and water is supplied to bring the water level in the tank A to the proper water level. Indicates the reached state. The period t ₃ from t ₄ is the time the load of the wash pump motor is constant. During the period from t ₂ to t ₄ , the air existing in the tank A and the supplied water are agitated and mixed with each other, resulting in noise. B is
In the waveform at the output end of the amplifying means 6, noise in the period from t ₂ to t ₄ indicates the result of amplification of the voltage A. C is the waveform at the output end of the noise removing means 7, and shows the state in which the B noise component has been removed. Here, the operation of the active filter used in the noise removing means 7 will be described. As a result of the analysis, it was found that the noise component shown in FIGS. 5A and 5B has an extremely large frequency component of 1 Hz. Therefore, in this embodiment, a low pass filter having a characteristic having a cut-off frequency of 1 Hz shown in FIG. 6 is used. FIG. 6 is a gain-frequency characteristic diagram of the noise removing means 7, where the horizontal axis represents frequency and the vertical axis represents gain. As a result of using the active filter having such characteristics, the voltage waveform with noise removed as shown in C is obtained.

Further, D is a waveform at the output end of the gradient detecting means 8, which is the voltage waveform of C differentiated with respect to time. Here, such a clear differential waveform is obtained as a result of using the noise removing means 7 described above, and in this sense, the effect of using the noise removing means 7 is extremely large. Vl
Is a resistor that constitutes the DC constant voltage source 6j and the slope determination means 9.
It is a voltage level determined by the ratio of 9a and 9b. t ₅ and t ₄ are the times when the level Vl and the differential waveform intersect, respectively, and t ₅
Indicates the moment when the gradient is up, and t ₄ indicates the moment when the gradient is down. E is a waveform at the output end of the gradient judging means 9, which outputs H when the setting of the operational amplifier 9d is larger than the set value of Vl and outputs L when it is small. As a result E, the output waveform is H between times t ₅ and t ₄ and L during the other periods. F is a waveform at the output end of the gradient selecting means 10, which is a timer 10a constituting the gradient selecting means.
Is set at the moment when the motor 3 is turned on, that is, from the time t ₁ to the time t _{6 at} which the proper water level is considered to be reached,
During this period, H output is made. The time t ₆ is an appropriate time between the times t ₅ and t ₄ . G is the waveform at the output end of the water supply valve driving means 11, and during the period from t ₁ to t ₅ , L is set by the waveform at the output end of the gradient selecting means 10 shown in F in the above figure, and the period from t ₅ to t ₄ . Becomes L by the output E of the gradient judging means 9. As a result, the water supply valve 4 is opened and water is supplied during the period from t ₁ to t ₄ . The water supply valve 4 is automatically closed at the time t _4, the water supply is stopped.

The operation of the above configuration will be described. First, the switch 18 of the washing pump motor is turned on. At this moment, the water is not yet supplied and the pump rotates stably with only the air load. This state is the period from t ₁ to t _{2 in} FIG. 5A. That is, since the rotation of the cleaning pump motor is stable, the capacitor terminal voltage of the cleaning pump motor does not change and there is no fluctuation. When the time t ₂ is reached, the control device 2 of the dishwasher shown in FIG. 1 outputs a signal to open the water supply valve 4. As soon as water is supplied from the water supply valve, the load on the cleaning pump motor becomes a mixture of air and water. The pump load will increase as the water supply increases, but unstable fluctuations will also be included when stirring water and air. The capacitor terminal voltage of the washing pump motor also shows the same variation depending on the amount of pump load. This state is the fluctuation in the period from time t ₂ to time t ₄ in FIG. 5A.
After this, if the inside of the washing pump is completely immersed in water, the pump load is only water and there is no fluctuation. The moment when this washing pump load is only water is detected as the optimum water level. Further, as the amount of supplied water increases, the absolute value of the voltage of the condenser 3b of the washing pump motor decreases as the load component changes from air to water. This is the change from time t ₄ to time t ₃ . That is, the voltage change of the condenser 3b of the washing pump motor detected by the load fluctuation detecting means 5 of the water level detecting device 1 from the moment the switch is turned on until the water supply is started and the water is stored in the tank A is shown in FIG. It is as shown in. Since this voltage change is small, it is amplified by the amplifying means 6. This is the voltage waveform shown in FIG. 5B. The voltage waveform including this noise component has its noise removed by the noise removing means in the next stage.
The waveform is as shown in. This voltage waveform is input to the gradient detecting means 8 in the next stage, differentiated to detect the gradient, and becomes a waveform shown in FIG. 5D. The gradient detecting means 8 detects the time positions of the instants t ₅ and t ₄ at which the absolute value of this gradient is Vl. The slope determining means 9 selectively selects and determines t ₄ of the two times t ₅ and t ₄ . The gradient judging means 9 compares the voltage value set by the operational amplifier 9d with the output of the gradient detecting means 8, and outputs H when the output of the gradient detecting means g is larger and outputs L when it is smaller. Therefore, from time t ₁
between t ₅ is L, between t ₅ of t ₄ are made of H, it exceeds t ₄ the output of L. That is, the signal having the voltage waveform shown in FIG. 5E is output. That is, the gradient determining means 19 outputs a signal of L at the instant t ₄ which is a downward gradient among the time-determined gradient values detected by the gradient detecting means 8. In other words, the slope determination means 9 determines the moment when the water level is the optimum level, that is, the moment when the slope value is a specific gradient value. On the other hand, the timer 10a that constitutes the water level determination means 10 is set with the minimum time from when the motor 3 is turned on until the water level in the tank A is considered to reach an appropriate value, and the switch 18 is turned on. The clock starts from the moment it is taken. This minimum time is represented by time t ₆ shown in FIG. 5F. This timer 10
a is from the start of timing until the time t ₆ is reached,
As shown in FIG. 5F, the H signal is output, and at the moment t ₆ is reached, the L signal is output. That is, the water level determination means 10 determines the moment when the appropriate water level is reached. This gradient judging means 9
The signals from both the water level determining means 10 and the water level determining means 10 are input to the transistors 11b and 11d that form the water supply valve driving means 11. In the coil 4a of the water supply valve 4 constituting the water supply valve driving means 11, the current from the DC constant voltage source 6j flows while one of the two transistors 11b and 11d is on, and both are off. When cut off. That is, the water supply valve 4 is a transistor 11b or 11d.
While one of them is open, water supply to the tank A is continued, and when both are off, the water supply valve is closed and water supply is stopped.

As described above, in the first embodiment of the present invention, the change in the current of the cleaning pump motor is detected through the noise removing means 7, and the change in the current is differentiated by the gradient detecting means 8 to be regarded as the gradient value.
The slope determining means 9 recognizes the moment when the absolute value of the slope reaches a predetermined value, and the water level determining means 10 determines whether the water level is appropriate or not.
Water supply valve drive means at the moment when the water level becomes appropriate after judging the unsuitability
It is configured such that 11 acts to turn off the water supply valve.

FIG. 7 shows a second embodiment of the present invention. 5-11
Has the same configuration as that of the first embodiment described above, and the water level determination means is provided even after a predetermined time set by the first time measurement means and the first time measurement means for starting the time measurement at the start of water supply.
A water supply valve closing means 36 forcibly closes the water supply valve when the water level determination means 10 does not detect the water level even after a predetermined time set by 10 has elapsed. The output is input to the water supply valve driving means 11.

In the above-mentioned configuration, the first timing means 35 starts timing with the start of water supply. A certain time is set in advance in the first time measuring means 35, and when the water level is not detected by the water level judging means 10 even after the set time elapses,
The water supply valve driving means 11 is provided with an output forcibly closing the water supply valve by the water supply valve closing means 36. If the set time is set to the maximum time for the water in the dishwasher tank to be filled with water from the start of water supply, the motor load fluctuation detecting means 5, the amplifying means 6, the noise removing means 7, the gradient detecting means of the washing pump are set. 8, gradient judgment means 9,
Even if the water level determination means 10 cannot detect that the water level has reached an appropriate level due to some malfunction, the water supply valve closing means 36 is activated by the first timing means 35, the water supply valve is closed, and water does not overflow from the dishwasher. .

FIG. 8 shows a third embodiment of the present invention. 5-11
Is the same configuration as that of the first embodiment, and 37 is a second timing means for timing with the start of water supply, and forcibly opens the water supply valve within a predetermined time set by the second timing means. The water supply valve opening means 38 is provided, and the output of the water supply valve opening means 38 is input to the water supply valve driving means 11.

In the above configuration, the second timing means 37 starts timing with the start of water supply. A second predetermined time is set in advance in the second time measuring means 37, and within this set time, the output of opening the water supply valve by the water supply valve opening means 38 is forcibly given to the water supply valve driving means 11. . If the set time is set to the minimum time for judging the slope by the slope judging means 9 from the start of water supply, within the second predetermined time, the water level judging means will not reach the proper water level. Even if 10 is erroneously detected, the water supply valve will not close and water supply can be continued.

FIG. 9 shows a fourth embodiment of the present invention, in which 5 to 11 have the same configuration as the embodiment of the first means, 39 is a third predetermined time set and the time counting is started together with the start of water supply. The reference numeral 3 denotes a time measuring means, and 40 denotes a water supply failure notifying means to which the output of the third time measuring means 39 and the output of the gradient detecting means 9 are inputted. The poor water supply notifying means notifies the poor water supply when the output value of the gradient detecting means does not change until the third predetermined time set by the third timing means is reached. FIG. 10 shows the time characteristic of the output of the gradient detecting means 8.

In the above configuration, the operation will be described. The third timing means 39 starts the timing of water supply and the timing of
The output of the gradient detecting means 8 is detected. In Figure 10, t
_{If the} water supply is started at ₁₀ , for example, the slope detecting means 8
If the output value of is normal (normal waveform 42), the maximum value (V _max )
At time t ₁₁ , the setting time set by the gradient detecting means 8 is set. In other words, like 41, between t ₁₀ and t ₁₁ ,
For example, when operating the dishwasher with the water tap directly connected to the water supply valve, the gradient detection output does not change at all,
The poor water supply notifying means 40 detects this and notifies the poor water supply.

FIG. 11 shows the fifth embodiment of the present invention.
The same construction as the embodiment of the means of
It is composed of water leak detection means 43 for inputting the output of the above and the output of the water level determination means 10. FIG. 12 shows the time characteristic of the output of the gradient detecting means.

In the above configuration, the operation will be described. In FIG. 12, the water supply start time is t ₁₀ , and the time when the proper water level is detected and the water supply valve is closed is t ₁₂ . After that, to enter the cleaning process,
If normal, the gradient detecting means 8 as shown by the waveform 44 in FIG.
The output of does not change. However, if there is water leakage for some reason, the water in the dishwasher will decrease and the gradient detection means 8
Output fluctuates as the waveform 44a in FIG. Its value is first
3 When the water content falls below a specific value as shown in FIG. Vl, the water leak detection means 43 determines that the water is running low and notifies the water leak.

A sixth embodiment is shown in FIGS. 13 and 14, and is shown in FIG.
Reference numeral 11 has the same configuration as the embodiment of the first means, and additionally has drainage end detecting means 45 for detecting the end of drainage based on the output of the gradient determining means 8. FIG. 14 is a block diagram of the dishwasher, and 46 is a drainage pump motor. Fig. 15 shows the voltage waveforms at various parts of the water level detector. In the figure, reference numeral 47 indicates the output of the motor load fluctuation detecting means 5, waveform 48 indicates the output of the noise removing means 7, and waveform 49 indicates the output of the gradient detecting means 8.

The operation of the above configuration will be described. After the cleaning process is completed, the drainage pump motor 46 is moved while moving the cleaning pump motor 3 shown in FIG. The time point is defined as t ₁₃ in FIG. Then, a completely opposite change from the first embodiment of the present invention occurs. That is, as shown by the waveform 47 in Fig. 15, the washing pump motor has a lighter load, such as a load of water, a mixed load of water and air, and an air load, and the terminal voltage gradually rises. There is no change. The output of the noise removing means has the waveform 48 in FIG. 15, and the output of the gradient detecting means has the waveform 49 in FIG. That is, the end of drainage can be detected by detecting the time t ₁₄ of the waveform 49 in FIG. 15 by the drainage end determination means 45, as in the case of the first embodiment. The difference from the first embodiment is that the downward slope is detected in the first embodiment, but in this embodiment, a time point at which the slope is an upward slope is detected.

FIG. 16 shows a seventh embodiment of the present invention, in which 5 to 11 have the same configuration as the embodiment of the first means, further set a fourth predetermined time and start timing at the same time as drainage starts. Fourth
When the output value of the slope detecting means 50 and the output value of the slope detecting means does not change from the start of drainage to the fourth predetermined time set by the fourth timing means 50, It is configured. FIG. 17 is a voltage waveform diagram detected by the motor load fluctuation detecting means 5. Reference numeral 52 is an output waveform of the motor load variation detecting means 5, and 53 is an output waveform of the gradient detecting means 8.

The operation of the above configuration will be described. When the drain pump motor 46 is operated and the cleaning pump motor 3 is moved, the load of the cleaning pump motor changes from the water load to the air load during normal operation as shown by the waveform 54 (broken line) in FIG. The voltage changes. Similarly, the output of the gradient detecting means always changes as shown by the waveform 55 (broken line) in FIG. However, if the drain outlet is clogged, the water does not decrease at all even if the drain pump is moved.Therefore, the output waveform of the washing pump motor capacitor terminal voltage is 52 in Fig. 17, and the output waveform of the slope detecting means is Fig. 17. Of 53
Does not change like. Therefore, the fourth timing means 50 measures the time when the drainage is started, and the output of the gradient detection means 8 is
For example, if there is no change until the fourth predetermined time between t ₁₃ and t _{14 in} FIG. 17, the drainage failure notification means 51 notifies the drainage failure.

Effects of the Invention As is clear from the above description, there are the following effects. By the first means, the water can be supplied to the proper water level without fail, and the water supply can be automatically stopped when the proper water level is reached.

Further, according to the second means, the motor load fluctuation detecting means, the amplifying means, the noise removing means, the gradient detecting means, the gradient judging means, and the water level judging means in the water level detecting device have reached an appropriate water level due to some failure. Even when it is not detected, the water supply valve closing means operates by the first timing function means, the water supply valve closes, and the water does not overflow from the dishwasher.

Further, in the third means, even if the water level determination means of the water level detection device does not reach an appropriate water level within the set time of the second timing function, it momentarily makes an erroneous detection and outputs a signal to close the water supply valve,
The water supply valve can be continued without closing the water supply valve.

Further, in the fourth means, when the dishwasher is operated with the water tap directly connected to the water valve of the dishwasher closed, the user is notified of the poor water supply, thereby opening the water tap to the user. You can also warn.

In the fifth means, by detecting water leakage during the cleaning process, the user is notified of an abnormality in the equipment,
The operation can be stopped or the safety can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram of a dishwasher showing a first embodiment of the present invention, FIG. 2 is a characteristic diagram showing load fluctuation characteristics of a washing pump, and FIG. 3 is a block diagram showing a configuration of a water level detection device. FIG. 4 is the same circuit diagram, FIG. 5 is a waveform diagram showing voltage waveforms of respective parts of the water level detection device, FIG. 6 is a characteristic diagram showing gain-frequency characteristics of noise removing means, and FIG. 7 is a second diagram of the present invention. FIG. 8 is a block diagram showing a third embodiment of the present invention, FIG. 9 is a block diagram showing a fourth embodiment of the present invention, and FIG. 10 is a gradient detecting means. Characteristic diagram showing output,
FIG. 11 is a block diagram showing the fifth embodiment of the present invention, and FIG.
FIG. 13 is a waveform diagram of this gradient detecting means, FIG. 13 and FIG. 14 are a sixth embodiment of the present invention, FIG. 13 is a block diagram of the water level detecting device, FIG. 14 is a block diagram of the entire dishwasher, FIG. 15 is a waveform diagram showing the voltage waveform of each part of the water level detection device, FIG. 16 is a block diagram of the water level detection device showing the seventh embodiment of the present invention,
FIG. 17 is a waveform diagram showing a voltage waveform detected by the load fluctuation detecting means, and FIG. 18 is a block diagram showing a configuration of a conventional dishwasher. 1 ... Water level detection device, 2 ... Dishwasher control device, 3
...... Washing pump, 4 …… Water supply valve, 5 …… Motor load fluctuation detection means, 6 …… Amplification means, 7 …… Noise removal means, 8
...... Gradient detecting means, 9 ...... Gradient determining means, 10 ...... Water level determining means, 11 ...... Water supply valve driving means, 35 ...... First timing means, 36 ...... Water supply valve closing means, 37 ...... Second Time keeping means, 38 ...
… Water supply valve opening means, 39 …… Third timing means, 40 …… Water supply failure notification means, 43 …… Water leak detection means, 45 …… Drainage end judgment means, 46 …… Drainage pump motor, 50 …… Fourth timekeeping means, 51 ... Drainage failure notification means.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP 62-292130 (JP, A) JP 63-181732 (JP, A) Actually opened 61-10172 (JP, U)

Claims (5)

(57) [Claims] 1. A cleaning pump for circulating cleaning water in a cleaning tank, a cleaning nozzle for injecting cleaning water, a cleaning pump motor for driving the cleaning pump, and a motor load fluctuation detection for detecting load fluctuation of the cleaning pump motor. Means, gradient detecting means for detecting the gradient of the output, gradient determining means for detecting that a predetermined gradient is reached, and water level determining means for determining the suitability or unsuitability of the water level of the dishwasher by this output And a water supply valve driving means for opening and closing the water supply valve, driving the cleaning pump motor and supplying water from the start of water supply in the cleaning process or the rinsing process, and the slope determination means determines a predetermined value from the signal of the slope detection means. Dishwasher that stops the water supply when it detects that the water level has reached the gradient. 2. A first predetermined time is a time from the start of water supply until the water level of the dishwasher reaches the maximum water level, and the first time measurement means is provided with first time measuring means for starting time measurement from the start of water supply. 2. The water supply is stopped when the first timing means measures the first predetermined time, if the water level determination means does not determine that the water level is appropriate by the time the first predetermined time is measured by the means. dishwasher. 3. A second predetermined time period from the start of water supply to the start of slope determination, and a second time measuring means for starting time measurement from the start of water supply, wherein the second time measuring means is second from the start of water supply. The dishwasher according to claim 1, wherein water is forcibly supplied until the predetermined time is measured. 4. A third predetermined time period from the start of water supply to a maximum gradient value, and a third time measuring means for starting time measurement from the start of water supply, wherein the second time measuring means is second from the start of water supply. The dishwasher according to claim 3, wherein when the slope detecting means does not detect the slope before the predetermined time is measured, the water supply failure is notified. 5. The dishwasher according to claim 1, wherein the gradient detecting means is operated for a predetermined period of time after the water supply is stopped to continue the gradient detection, and when a gradient change is detected, a water leak is notified.