JPH01192326A - Dish washer - Google Patents

Abstract

PURPOSE:To automatically discharge the same cleaning water when the temperature of the cleaning water to remain in a cleaning tank is lower than the suitability of the cleaning by cleaning a dish thereafter with a cleaning water to remain in the cleaning tank based on a prohibiting control for water discharging actions by a cleaning washing means and discharging the cleaning water in a cleaning tank 1b based on the allowable control for the water discharging actions by a water discharging means. CONSTITUTION:While a cleaning water remains in a cleaning tank 1b as it is after the washing of a cleaning washing means 3 is completed, a discriminating means 6 discriminates the reduction to less than the proper cleaning temperature based on the detecting result of a detecting means 5, and then, a water discharging means 4, while an unnecessary manual switch,etc., are not provided, discharges always, automatically and surely the cleaning water to remain in the water cleaning tank 1b based on the water discharging action allowable control by a water discharging control means 7. Without being accompanied by an extra operation, it can be always automatically prevented that the cleaning water in the cleaning tank 1b to reduce the unnecessary temperature is used to the later dish washing by mistake.

Description

[Detailed description of the invention]

[Industrial application field] The present invention relates to improvements in dishwashers.

[Prior art]

Conventionally, in this type of dishwasher, in the washing cycle corresponding to the first cycle, washing water is supplied by a water supply valve through the washing chamber into a washing tank located at the bottom of the washing chamber, and when the water supply ends, The washing water in the washing tank is pumped up by a washing pump and sprayed and circulated into the washing chamber from a washing nozzle, and after washing the dishes after mixing detergent with the circulating washing water, the circulating washing water is drained by a drain pump. In subsequent rinse cycles, the same process as in the previous wash cycle was repeated without detergent to rinse the dishes, and the wash water used in the final rinse cycle was used directly for washing in the next wash cycle. There are some (for example, see Japanese Unexamined Patent Publication No. 175338/1983). [Problems to be Solved by the Invention] Normally, in a washing cycle, the temperature of the washing water should be set at 60°C (60°C) in order for the detergent to remove stains best.
C) Preferably before or after. - On the other hand, in each rinse cycle, in order to obtain a sufficient sterilizing effect, it is desirable that the temperature of the cleaning water is 80 ("C) or higher. From this point of view, if the configuration is as described above, the cleaning cycle Although it is believed that the temperature of the wash water in and in each rinse cycle can be maintained at the same temperature as during the detergent wash and detergent-free rinse, respectively,
If cleaning is not performed for a long time, the user may not notice that the temperature of the cleaning water in the cleaning tank has dropped unnecessarily, and the same cleaning water may be used in the next cleaning cycle. Furthermore, when the above-mentioned temperature drop is noticed, it is conceivable to drain the wash water using an appropriate manual switch, but moating the manual switch is troublesome and the user may forget to operate it. Therefore, in order to cope with such a problem, the present invention has been developed to automatically drain the washing water remaining in the washing tank when the temperature of the washing water remaining in the washing tank drops below the appropriate temperature. This is what we are trying to do. [Means for solving the problem] In solving the problem, the structural features of the present invention are as follows:
As illustrated in FIG. 1, a water supply means 2 supplies washing water at a predetermined temperature through the washing chamber 1 into a washing tank lb opened at the bottom of the washing chamber 1, and a water supply means 2 supplies washing water in the washing tank lb to the washing chamber 1. A washing and rinsing means 3 for washing or rinsing the tableware 1a in the washing chamber 1 by refluxing water into the washing chamber 1;
A dishwasher equipped with a drainage means 4 for discharging the wash water flowing back into the washing tank lb, a detection means 5 for detecting the temperature of the wash water in the wash tank lb or a physical quantity related thereto, and a detection means 5 for detecting the temperature of the wash water in the wash tank lb. As a result, a determining means 6 determines when the temperature of the cleaning water remaining in the cleaning tank lb reaches a value lower than the appropriate cleaning temperature, and a discriminating means 6 that determines when the temperature of the cleaning water remaining in the cleaning tank lb reaches a value lower than the appropriate cleaning temperature, and a discriminating means 6 that determines when the temperature of the cleaning water remaining in the cleaning tank lb reaches a value lower than the appropriate cleaning temperature, and draining water of the drainage means 4' when the cleaning and rinsing means 3 completes rinsing. The cleaning and rinsing means 3 is provided with a drainage control means 7 that prohibits the drainage action of the drainage action by the drainage control means 7 and controls the drainage action of the drainage means 4 to be permitted when the determination means 6 makes a determination. The washing water remaining in the washing tank 1b is used to wash the dishes afterwards, and the drainage means 4 discharges the washing water in the washing tank 1b under the drainage action permission control by the drainage control means 7. The reason is that the water is drained away. [Operation and Effect] By configuring the present invention in this way, if the drainage control means 7 prohibits the drainage action of the drainage means 4 when the washing and rinsing means 3 completes rinsing, the dishes in the washing chamber 1 can be cleaned. The wash water used for rinsing 1a remains in the wash tank lb while being refluxed. In such a case, the temperature of the cleaning water in the cleaning tank 1b has been lowered to the appropriate temperature for cleaning through the rinsing process. Therefore, if the dishes are subsequently washed with detergent in the washing and rinsing means 3 using such washing water, the stains that are difficult to remove at high temperatures attached to the dishes will be easily and reliably removed. In other words, focusing on the fact that the temperature of the wash water used for rinsing drops to the appropriate temperature for washing when rinsing is completed, the wash water is controlled to be controlled by the drain control means 7 to prevent draining, without draining the water. Since it is left in the washing tank lb and used for the next washing of dishes with detergent mixed in, it not only helps to save water, but also ensures that the appropriate washing temperature is maintained when washing dishes, and when rinsing dishes. To ensure an appropriate temperature for rinsing, and to reliably realize rinsing accompanied by cleaning and sterilizing stains that are difficult to remove from dishes. In addition, when the cleaning water remains in the cleaning tank 1b after rinsing of the cleaning and rinsing means 3 as described above, the determination means 6 determines that the temperature is lower than the appropriate cleaning temperature based on the detection result of the detection means 5. When it is determined that the water level has decreased, the drainage means 4 drains the cleaning tank l without installing an unnecessary manual switch or the like under the drainage action permission control by the drainage control means 7.
Since the cleaning water remaining in tank lb is always automatically and reliably drained, there is no need for extra operations, and the cleaning water in the cleaning tank lb whose temperature has dropped unnecessarily is not mistakenly used for subsequent dishwashing. This can always be automatically prevented. [Example] Hereinafter, an example of the present invention will be described with reference to the drawings.
3 and 3 show the overall structure of a dishwasher according to the present invention. The main body of this dishwasher (hereinafter referred to as washing machine main body B)
As shown in FIG. is installed.The water supply valve 30 is opened by selectively energizing its solenoid SV (see Fig. 3).
Washing water of 80 ('C) or more from a hot water source (not shown) is supplied through the washing chamber 20 into a washing tank 21 extending downward from the left side of the bottom wall of the washing chamber 20. In addition,
In FIG. 2, reference numeral 22 indicates a drainboard, and reference numeral 23 indicates a heat insulating material. A cleaning pump 40 is attached to the center of the peripheral wall of the cleaning tank 21 via a heat insulating material 23.
is driven by a cleaning electric motor Mp coaxially assembled to this cleaning pump 40 to pump up the cleaning water in the cleaning tank 21, and a cleaning nozzle 50 pivotally supported at the center of the bottom wall of the cleaning chamber 20.
The washing water is sprayed and circulated into the washing chamber 20 to wash the dishes 70a, 70b, and 70c placed on the washing shelf 60. The drain pump 80 is driven by a drain electric motor Md coaxially assembled to the drain pump, and the washing tank 2
The cleaning water in the cleaning tank 21 is pumped out through a pipe 21a extending from the bottom of the peripheral wall 1 and discharged from the pipe 81 and the drain pipe 24. Note that the drain pipe 24 also plays the role of draining overflow water from the cleaning water inside the cleaning chamber 20. Next, the electric circuit configuration of this embodiment will be explained with reference to FIG. 3. The operating circuit 90 has a normally open push button type cleaning start switch 91. One end is grounded, and the other end is connected to the positive terminal of a DC power source (not shown) via a resistor 92. When the cleaning start switch 91 is closed, the operating circuit 90 generates a cleaning start signal at a low level from a common terminal of the cleaning start switch 91 and the resistor 92 (hereinafter referred to as an output terminal 93). Further, this cleaning start signal disappears when the cleaning start switch 91 is opened. The water amount detection circuit 100 includes a normally open float switch 101
The float switch 101 is operably interposed in the drainboard 22 (see FIG. 2). Further, as shown in FIG. 3, the float switch 101 is grounded at one end.
The other end of 1 is connected to the positive terminal of the DC power supply via a resistor 102. When the cleaning water in the cleaning tank 21 reaches a predetermined level La or higher corresponding to a full water state, the float switch 101 is closed by the operation of the float. Further, when the cleaning water in the cleaning tank 21 is lower than the predetermined level La, the float 101 is opened by returning to its non-operating state. Due to the structure, this float switch 101 and resistor 102
A water amount detection signal is generated at a low level from a common terminal (hereinafter referred to as output terminal 103). Further, this water amount detection signal disappears when the float switch 101 is opened. The temperature detection circuit 110 has a temperature sensor 111, which is directly fixed to the peripheral wall of the cleaning tank 21 as shown in FIG. As shown in the figure, one end of this temperature sensor 111 is grounded, and the other end of this temperature sensor 111 is connected to a resistor 112.
It is connected to the positive side terminal of the DC power supply via. Accordingly, the temperature detection circuit 110 applies the DC voltage (+Vc) from the DC power supply to the temperature sensor 111 and the resistor 11 in accordance with the temperature detected in the cleaning tank 21 by the temperature sensor 111.
2, and the partial pressure result is used as a temperature detection signal at a level corresponding to the actual temperature of the cleaning water in the cleaning tank 21, and the common terminal of the temperature sensor 111 and the resistor 112 (
(hereinafter referred to as the output terminal 113). The microcomputer 120 operates the operation circuit 90 and the water amount detection circuit 1 according to the flowcharts shown in FIGS. 4 to 7.
00 and temperature detection circuit 110 to execute a computer program, and during this execution, each relay coil 130a. Each drive circuit 13 connected to 140a and 150a, respectively.
Performs arithmetic processing necessary for drive control of 0, 140, and 150. However, the above-mentioned computer program is stored in the ROM of the microcomputer 120 in advance. Each drive circuit 130, 140° 150 is controlled by a microcomputer 120, and each relay coil 130a, 14
0a and 150a are selectively excited. The normally open type relay switch 130b is connected to the relay coil 130a.
This relay switch 1 constitutes a relay.
30b closes only when the relay coil 130a is energized, and applies a power supply voltage from a commercial type 1 lps to the solenoid Sv to energize it. The normally open type relay switch 140b is connected to the relay coil 140a.
This relay switch 1 constitutes a relay.
40b closes only when the relay coil 140a is energized, and applies the power supply voltage from the commercial power supply ps to the cleaning motor Mp to drive it. In addition, a normally open relay switch 150
b constitutes a relay together with the relay coil 150a, and this relay switch 150b is connected to the relay coil 1.
It closes only under the excitation of 50a, and applies the power supply voltage from the commercial power source Ps to the drainage motor Md to drive it. In this embodiment configured as described above, if the microcomputer 120 is activated and a cleaning start signal is generated from the operation circuit 90, the microcomputer 120 can be activated.
0 starts executing the computer program at step 200 according to the flowchart of FIG.
0, a cleaning start signal from the operating circuit 90 is read in step 220, and based on the read contents, rYEsJ is determined in step 230, and the computer program proceeds to a cleaning control routine 240. Then, the microcomputer 120 starts executing the cleaning control routine 240 at step 240a,
In step 241, a solenoid excitation output signal necessary to excite the solenoid Sv of the water supply valve 30 is generated, and in response to this, the drive circuit 130 excites the relay coil 130a, the relay switch 130b is closed, and the water supply valve 30 is opened by energizing the solenoid Sv, and supplies cleaning water from the hot water source into the cleaning tank 21. However, step 2
When the water M detection circuit 100 generates a water amount detection signal during the repetition of the determination with rNOJ in step 43, the microcomputer 120 outputs the same water amount detection signal in step 24.
Based on the reading result, rYESJ is determined in step 243, and the solenoid excitation output signal is extinguished in step 243a. Therefore, the drive circuit 130 demagnetizes the relay coil 130a based on the extinction,
The relay switch 130b is opened, the water supply valve 30 is closed by demagnetization of the solenoid Sv, and the water supply source is disconnected from the cleaning chamber 2.
Stop water supply to 0. Thereby, the cleaning tank 21 is maintained full of cleaning water. Note that the predetermined level La in step 243 is stored in advance in the ROM of the microcomputer 12(1). After the calculation in step 243a, in step 243b, the microcomputer 120 generates a cleaning output signal necessary for driving the cleaning motor Mp, and resets and starts a timer (built in the microcomputer 120). Then, the drive circuit 140 responds to the cleaning output signal from the microcomputer 120 and activates the relay coil 1.
40a is energized, the relay switch 140b is closed, and the cleaning pump 40 is driven by the cleaning motor Mp to pump up the cleaning water in the cleaning tank 21 and inject and circulate it into the cleaning chamber 20 from the cleaning nozzle 50. As a result, each tableware 70a
~70b is washed with washing water mixed with detergent. Further, the timer starts counting by its reset start. Therefore, the time value T of the timer is the predetermined cleaning time Tp.
(previously stored in the ROM of the microcomputer 120), the microcomputer 120 determines that the cleaning is complete, and in step 244, the microcomputer 120
In step 244a, the cleaning output signal is eliminated, and in response, the drive circuit 140 turns on the relay coil 1.
40a, and the cleaning pump 40 switches to the relay switch 1.
Pumping up of the cleaning water is stopped by stopping the cleaning motor Mp as the cleaning motor Mp is opened. After that, the microcomputer 120 performs step 24.
At step 4b, a drainage output signal necessary for driving the drainage motor Md is generated, and the timer is reset and started. Then, the drive circuit 150
Relay coil 15Qa in response to the drainage output signal from 0
is excited, the relay switch 150b is closed, and the drain pump 80 is driven by the drain motor Md to drain the cleaning tank 2.
The cleaning water in the tank 1 is pumped out and discharged from the pipe 81 and the drain pipe 24. Also, the timer starts counting due to its reset start. When the measured value T of this timer reaches the predetermined drainage time Td (previously stored in the ROM of the microcomputer 120), the microcomputer 120 determines that the drainage has ended, and in step 245, the microcomputer 120 issues rYESJ. The determination is made, the drainage output signal is extinguished in step 245a, and the drive circuit 150 activates the relay timer 150a.
demagnetizes the drain pump 80, and the relay switch 150b
Discharge of washing water is stopped by stopping the drain motor Md when the drain motor Md is opened. When the cleaning control routine 240 has been executed m%, the microcomputer 120 advances the computer program to the rinsing control routine 250 (see FIG. 4). Then, the microcomputer 120
Rinse control routine 25 according to the flowchart in the figure.
0 begins at step 250a, and each step 2
51 to 254a, each step 241 to 244a
The same arithmetic processing as that in (see FIG. 5) is performed. As a result, after the cleaning water is supplied to the cleaning tank 21 via the water supply valve 30 until it becomes full, the cleaning water pumped out from the cleaning tank 21 by the cleaning pump 40 enters the cleaning chamber 20 from the cleaning nozzle 50. The spray is circulated to rinse each tableware 70a to 80c without detergent. When the rinse control routine 250 proceeds to step 254b, the microcomputer 120 performs step 254b.
In step 210, the number data N, which has been initialized to zero, is updated to "1", and in step 255, it is determined as "NO" based on N=1, and after that, each step 255a to 25
6a, the same arithmetic processing as that in each step 244b to 245a is performed. Thereby, the cleaning water in the cleaning tank 21 is discharged by the drain pump 80 in the same manner as described above. After completing the first rinse and drain in this way,
The microcomputer 120 again performs each step 25.
1 to 254b are performed, and each tableware 70a to
The second rinse at 70c is performed as described above. The rinse control routine 250 then performs step 254b.
, the microcomputer 120 proceeds to step 25.
In step 4b, N=2 is updated, and in step 255, N=2.
Based on this, it is determined that it is rYEsJ. In other words, the microcomputer 120 runs the rinse control routine 250 from step 255 to step 2 on the premise that N=2.
After prohibiting the transition to 55a, step 220 (fourth
(See figure). Therefore, the washing water used for the second rinsing of each tableware 70a to 70c is transferred to the washing tank 2, except for the portion that flowed out from the drain pipe 24 during rinsing.
It remains stored within 1. Further, the temperature of the washing water in the washing tank 21 gradually decreases while rinsing each tableware 70a to 70c, and after rinsing is completed, the temperature decreases to around 60°C. At this stage, if the cleaning start signal from the operating circuit 90 continues to be generated, the microcomputer 120
However, as described above, rYEsj in step 230
After the determination, the cleaning control routine 240 is executed. Further, at this time, instead of the above-mentioned dishes 70a to 70c, other dishes with stains that are difficult to remove at high temperatures are placed on the washing shelf 60. Then, the microcomputer 120 performs the arithmetic processing in each step 241 to 243a in accordance with the flowchart of FIG. 5 in the same manner as described above, and replenishes the insufficient amount of washing water in the washing tank 21. As a result, the cleaning tank 21 is kept full of cleaning water at around 60°C. After that, the microcomputer 120 performs each step 24.
3b to 244a are performed in the same manner as described above, and the cleaning pump 40 injects and circulates the cleaning water in the cleaning tank 21 into the cleaning chamber 20 from the cleaning nozzle 50. Therefore, the other tableware is washed with washing water at around 60° C., with detergent mixed in. As a result, stains that are difficult to remove at high temperatures and adhered to the other tableware can be easily and reliably removed. After cleaning in this manner, the microcomputer 120 performs each step 244b to 244.
Arithmetic processing and rinse control routine 250 in 5a
The arithmetic processing is performed to achieve the same drainage, rinsing, etc. as described above. As understood from the above explanation, focusing on the fact that the temperature of the wash water used for the second rinse drops to around 60°C at the end of rinsing, the wash water is stored in the wash tank 21 without being drained. This system is used to wash the next dish that contains detergent, which not only helps save water, but also ensures that the washing water is at a temperature (around 60°C) that is suitable for washing dishes that contain detergent. In addition, when rinsing dishes, it is possible to secure washing water at a rinsing temperature (approximately 80° C.), and it is possible to reliably achieve rinsing accompanied by removal of stains that are difficult to remove at high temperatures and sterilization of dishes. Furthermore, after determining rYESJ in step 255,
If the determination in step 230 is rNOJ, the microcomputer 120 proceeds to execute a hot water temperature determination routine 260 (see FIG. 4). Then, the microcomputer 120 executes the water temperature determination routine 260 in step 26 according to the flowchart in FIG.
0a, and in step 261 the water amount detection circuit 10
Read the water amount detection signal from 0. At this stage, if the water amount detection signal is not generated from the water amount detection circuit 100, the microcomputer 120 in step 262
NO", and the process moves to the calculation process in step 220. On the other hand, if the determination in step 262 is rYEsJ, the microcomputer 120
At step 62a, the value of the temperature digital signal from the temperature detection circuit 110 is converted into a digital temperature signal, and this digital temperature signal is compared with the reference temperature [)o for determination at step 263. However, the reference temperature DO is previously stored in the ROM of the microcomputer 120 as a value of around 60°C. If D≧DO holds true, the microcomputer 120 executes step 263 based on the judgment that the temperature of the cleaning water in the cleaning tank 21 is maintained at a value of around 60°C.
It is determined that it is rNOJ. Conversely, if D<Do holds true, the microcomputer 120 proceeds to step 263 based on the judgment that the temperature of the cleaning water in the cleaning tank 21 has fallen to a value unsuitable for cleaning. rYEsJ, and each step 263
3 to 264a, each step 255a to 256a
Performs the same arithmetic processing as in . For this reason,
After the second rinse is completed, the cleaning water stored in the cleaning tank 21 is automatically drained by the drain pump 80 in the same manner as described above. Therefore, the washing water in the washing tank 21 whose temperature has dropped unnecessarily can be automatically prevented from being mistakenly used for subsequent dishwashing. Next, a modification of the above embodiment will be explained. In this modification, a part of the flowchart in FIG.
The structure is characterized by the changes as shown in the figure, and the changes in the flowchart in FIG. 7 as shown in FIG. Note that the other configurations are substantially the same as those of the previous embodiment except that the temperature detection circuit 110 is omitted. In this modified example configured as above, as in the previous embodiment, when the computer program proceeds to step 255 (see FIGS. 6 and 8) of the rinse control routine 250, if it is determined that it is rYEsJ. , the micro combinator 120 resets and starts another timer (hereinafter referred to as a second timer) in step 255b. As a result, this second timer starts counting time. Note that the second timer is built into the microcomputer 120. After that, similarly to the embodiment described above, when the computer program proceeds to step 262 (see FIGS. 7 and 9) of the hot water temperature determination routine 260, [if the determination is YESj, the microcomputer 120 Step 26
The process moves on to the determination in step 3A. If the time value 'rα of the second timer □ is equal to or less than the predetermined time Tαo (=60 minutes), the temperature of the cleaning water in the cleaning tank 21 is 60°C.
Based on the judgment that the previous and subsequent values are maintained, the microcomputer 120 selects "NOJ" in step 263A.
Then, the process moves to arithmetic processing in step 220. On the other hand, if Tα>TαO holds true, the microcomputer 120 determines that the temperature of the cleaning water in the cleaning tank 21 has decreased to a temperature unsuitable for cleaning, and in step 263A, the microcomputer 120 selects rYESJ. Then, the calculation processing in each step 263a to 264a is performed in the same manner as in the previous embodiment. Therefore, after the completion of the second rinse, the cleaning water stored in the cleaning tank 21 is automatically drained by the drain pump 80 in the same manner as described above. Therefore,
It is possible to always automatically prevent the washing water in the washing tank 21 whose temperature has dropped unnecessarily from being mistakenly used for subsequent dishwashing. Here, the basis for determining the above-mentioned predetermined time Tα0 will be explained. When the temperature drop of the wash water in the wash tank 21 after the completion of the second rinse was investigated through experiments, it was found that the drop in the temperature of the wash water can be specified by the characteristic curve shown in Fig. 10. was confirmed. According to this, if the second rinse is assumed to end at point La (corresponding to time zero) on the characteristic curve, then the temperature of the wash water decreases almost linearly, and 50 (' C) when it reaches 60
You can see that (minutes) have passed. Therefore, if we take into account that the cleaning water is not washed when the temperature of the cleaning water is in the range below 50 ("C) (see symbol A in FIG. 10), the predetermined time Tα
It is understood that 0 may be defined as 60 (minutes), for example.

[Brief explanation of the drawing]

FIG. 1 is a diagram corresponding to the configuration of the invention described in the claims, FIGS. 2 and 3 are overall configuration diagrams showing one embodiment of the present invention, and FIGS. A flowchart showing the operation of the microcomputer, FIG. 8 is a main part flowchart showing a modification of the flowchart in FIG. 6, FIG. 9 is a flowchart showing a modification of the flowchart in FIG. 7, and FIG. FIG. 3 is an explanatory diagram of a state in which the temperature of the washing water decreases after the second rinsing is completed. Explanation of symbols B...Washing machine body, Md...Drainage motor, Mp...
・Cleaning motor, Sv... Solenoid, 20... Washing chamber, 21... Washing tank, 30... Water supply valve, 40...
...Cleaning pump, 50...Cleaning nozzle, 70a-70
C... Tableware, 80... Drain pump, 120...
Microcomputer, 130, 140.150...
Drive circuit, 130a, 140a, 150a...Relay coil, 130b, 140b, 150b...Relay switch.

Claims (1)

[Claims] Water supply means for supplying washing water at a predetermined temperature through the washing chamber into a washing tank opened at the bottom of the washing chamber, and washing water in the washing tank flowing back into the washing chamber to wash dishes in the washing chamber or a cleaning rinsing means for rinsing;
In a dishwasher equipped with a draining means for draining the washing water that flows back into the washing tank upon completion of washing or rinsing of the washing and rinsing means, the temperature of the washing water in the washing tank or a physical quantity related thereto a detection means for detecting, a determination means for determining when the detection result by the detection means indicates that the temperature of the cleaning water remaining in the cleaning tank reaches a value lower than the appropriate cleaning temperature; and a drainage control means for controlling the drainage action of the drainage means to be prohibited when the rinsing of the means is completed, and for controlling the drainage action of the drainage means to be permitted when the determination means makes a determination, so that the washing and rinsing means The dishes are subsequently washed using the washing water remaining in the washing tank under the control of prohibiting the drainage action by the drainage control means, and the drainage means is under the control of allowing the drainage action of the drainage control means. A dishwasher characterized in that the washing water in the washing tank is drained.