JP4743619B2 - dishwasher - Google Patents

Description

  The present invention relates to a dishwasher, and more particularly, to an automatic dry operation control system thereof. When a tableware that has been cleaned and dried is taken out of the dishwasher, the surface of the tableware is always dry without being wetted by condensation. It can be taken out.

  The dishwasher automatically executes a series of washing operations such as washing, rinsing and drying, and then stops. The cleaning operation may end when the temperature inside the cleaning tank becomes considerably high due to high temperature rinsing, high temperature drying, etc. In this case, the temperature in the cleaning tank gradually decreases after the cleaning operation is completed. To do. Thus, when the temperature in the cleaning tank decreases, the inner surface of the cleaning tank, the surface of the tableware, and the like become wet with condensation. In order to prevent this, an invention in which the inside of the cleaning tank is automatically ventilated with a ventilation fan in the process of cooling the cleaning tank after the completion of the cleaning operation is known, and an example thereof is disclosed in Japanese Patent Laid-Open No. 5-161589. JP-A-3-272726.

  The invention described in the above-mentioned Japanese Patent Application Laid-Open No. 5-161589 is focused on the fact that the relative humidity in the tank increases and condensation occurs as the temperature in the cleaning tank decreases after the completion of the cleaning operation. In the process in which the temperature in the washing tank is lowered after the drying process is finished, the drying fan is operated each time the temperature in the tank is lowered by the predetermined temperature ΔT to ventilate the inside of the washing tank. Since the predetermined drop temperature ΔT is such that the humidity in the washing tank does not reach the saturation humidity, the inside of the tank is ventilated before reaching the saturation humidity due to the drop in the washing tank temperature. Therefore, the tableware is not wetted by condensation while being stored (or left) in the washing tank.

  In addition, what is described in the above Japanese Unexamined Patent Publication No. 3-272726 is that when the high temperature rinse is performed and the drying process is performed with the residual heat and the cleaning operation is finished, the temperature in the cleaning tank is higher than the outside air, and then The temperature inside the washing tank is naturally cooled, and the humidity inside the washing tank increases as the temperature inside the washing tank decreases, and the process takes place through condensation and wetting. When the temperature is higher than a predetermined temperature (for example, 2 ° C.), the table is stored in the washing tank as the temperature in the washing tank decreases after the washing is finished by operating the ventilation fan to ventilate and lowering the temperature in the washing tank. Is to prevent wetting due to condensation.

The prior art described above solves the problem of dew condensation that occurs in the process in which the temperature in the cleaning tank decreases to the outside air temperature after the cleaning operation is completed.
By the way, if the tableware is taken out immediately after the series of cleaning operations is completed and naturally cooled, the situation is that the tableware taken out from the washing tank is wet by performing the anti-condensation operation according to the above-described conventional technology. Can be avoided.

  However, in reality, it is often stored (or left) in the dishwasher until the next morning after the dishes are washed and dried, and then taken out the next morning. Even in the conventional automatic drying operation for preventing condensation, the tableware taken out from the washing tank is often wet in cold regions. It has been confirmed that this phenomenon occurs when the room (in the kitchen room) is considerably cooled and heated in the next morning and the room temperature rapidly rises. And this phenomenon is a phenomenon that occurs in the process in which the room temperature once drops significantly and then rapidly rises, so this is the dew condensation phenomenon that occurs in the process where the temperature inside the washing tank is cooled by the outside air and decreases. Completely different. Therefore, this phenomenon cannot be solved by the above prior art.

The above problem can be solved by detecting this when the washed tableware is stored in the washing tank until the next morning and intermittently ventilating from an appropriate time in the early morning. However, this is a phenomenon that occurs in the early morning when it is extremely cold in winter, so if the minimum room temperature in the next morning is below the predetermined temperature that may cause condensation, the ventilation operation condition is wasteful ventilation operation. Some degree can be avoided. However, even if you do so, the surface of the dishes in the washing tub will not always get wet in the morning when the temperature drops to the specified temperature. As a result, there is a possibility that the ventilation operation will be performed wastefully. There is also a possibility that the ventilation operation is wasted after getting wet.
For example, it is not preferable that the automatic ventilation operation is performed wastefully in the early morning because of problems of energy loss and indoor noise due to ventilation.
JP-A-5-161589 JP-A-3-272726

  The object of the present invention is to devise automatic dry operation control so as to solve the above-mentioned problems concerning the dishwasher and to appropriately perform the ventilation operation of the washing tub for the necessary limit. is there.

Means for solving the above problems are based on the following (a) to (d) on the premise of a dishwasher that performs ventilation operation by operating a drying fan when tableware is stored in a washing tub. It is.
(B) a dishwasher comprises a door opening and closing detecting means, Bei room temperature sensor Eteori,
(B) having a judging means for comparing the room temperature T0 and the reference temperature Ts to judge the level;
(C) it has a determination means for determining that the room temperature was worth is the reference rise temperature Tu above,
(D) After completion of the cleaning / drying operation, the indoor temperature T0 is lowered to the reference temperature Ts or lower with the door opening / closing detecting means not detecting the opening of the door , and the indoor temperature rise is equal to or higher than the reference raised temperature Tu. In some cases, control means to operate the drying fan for a predetermined time to ventilate the washing tank.
In addition, it can replace with said (c) and can also be based on the following (e).
(E) It has calculation means for calculating the difference (T0−T1) between the cleaning tank internal temperature T1 and the room temperature T0, and has a determination means for determining T0−T1> ΔT ( reference temperature difference ).
However, in this case, it is necessary to provide a cleaning tank temperature sensor for detecting the cleaning tank temperature T1, and this cleaning tank temperature sensor can use an existing cleaning water temperature sensor. .

[Action]
If it is detected by the door opening / closing detection means that the door has been opened after the end of the cleaning operation ("door open"), it is considered that the tableware in the cleaning tank has been removed.
Tableware is left in the washing tank after the washing operation by a series of steps such as washing, rinsing, drying, etc., and the room temperature (room temperature in the kitchen room, etc.) falls below the reference temperature Ts (for example, 5 ° C.). After that, when the room is heated and rises to a certain temperature (for example, about 20 ° C.), the tableware in the washing tub is wet with condensation. An example of the trend of room temperature, temperature inside the washing tank, bottom temperature of the washing tank, residual water temperature, and tableware temperature at this time is as shown in FIG.
Even if the washing tub and the tableware in the tub were once warm-air dried during the drying process, if the room (kitchen room) cools down significantly at night and is heated the next morning, the tableware in the washing tub will dew May get wet. However, it is not always known why this phenomenon is caused, and there is still no attempt to solve this problem.

  When the time-dependent changes in the cleaning tank temperature B, cleaning tank bottom surface temperature C, residual water temperature D, tableware temperature E, etc. after the cleaning operation are traced, these gradually decrease with time as shown in FIG. Then, it settles down to a low temperature and stabilizes. In the example of FIG. 1, the room heating is stopped approximately two hours after the completion of the cleaning operation, and the room temperature A rapidly decreases. After the heating is stopped, the room temperature A rapidly decreases and thereafter becomes substantially constant, and the temperature B in the cleaning tank (and the temperature C at the bottom of the cleaning tank), the tableware temperature E, etc. gradually decrease with a decrease in the room temperature A. When the room temperature A begins to rise rapidly in the next morning (at 10 hours in FIG. 1), the cleaning tank temperature B (and cleaning tank bottom temperature C), residual water temperature D, tableware surface The temperature E rises in this order following the rise in room temperature.

Based on the trend of temperature rise such as the temperature B in the washing tank accompanying the rise in the room temperature A, it is estimated that the tableware in the washing tank is dewed and wet the following morning due to the following phenomenon. Is done.
When the drying process is finished, the temperature B in the washing tank suddenly decreases immediately after that, and then gradually decreases. At this time, the tableware temperature E decreases with the same trend as the cleaning bath temperature B.
When the room is heated the next morning, the room temperature A rapidly rises, and as the room temperature A rises, the cleaning tank temperature B (and the cleaning tank bottom temperature C) rises with a delay. However, at this time, the tableware temperature E gradually rises at a level considerably lower than the cleaning bath temperature B.

   On the other hand, the humidity (relative humidity) W in the cleaning tank gradually increases as the temperature B in the cleaning tank decreases (humidity graph W in the cleaning tank in FIG. 1). Thereafter, when the room temperature A rapidly rises and the cleaning bath temperature B begins to rise suddenly, the cleaning bath humidity w further rises accordingly, and gradually increases with the subsequent rise of the cleaning bath temperature B. The humidity rises and eventually rises to almost 100% humidity. This is because the evaporation of the water film adhering to the inner surface of the cleaning tank due to the rapid increase in the temperature in the cleaning tank is promoted with the rapid increase in the temperature in the cleaning tank (especially the temperature of the wall of the cleaning tank). Guessed. Then, the air in the cleaning tank whose relative humidity has reached nearly 100% will come into contact with the considerably cooler tableware to condense and wet the tableware surface.

  From the above, when the room temperature A detected by the indoor temperature sensor falls below the predetermined reference temperature Ts, the temperature change then starts to rise, and when it starts to rise more rapidly, after a while, The temperature B in the cleaning tank starts to rise rapidly, and accordingly, the humidity w in the cleaning tank rises to nearly 100%. When the humidity rises to near 100%, it starts to condense when it touches the tableware that has been cooled to the vicinity of the reference temperature Ts (for example, 5 ° C.). In such a situation, when the room temperature A rapidly rises and the temperature B in the washing tank suddenly rises and it is reliably predicted that the surface of the tableware will start to condense, it is predicted in advance and dried at the stage before the condensation starts. By operating the fan and ventilating the inside of the washing tub to room air (air having a higher temperature and lower humidity than the air in the washing tub), the above phenomenon that the tableware surface gets wet can be prevented efficiently and reliably. it can.

The lowest indoor temperature at which tableware can get wet as described above is an empirical temperature of approximately 5 ° C. Therefore, it is appropriate that the minimum temperature condition (reference temperature Ts) of the room temperature for starting the automatic dry operation is 5 ° C. or less.
The room temperature is lower than the temperature in the washing tank in the morning where the cooling is remarkable, and the temperature in the washing tank and the tableware temperature are reduced to about room temperature, but when the room is heated the next morning, the room temperature ( The room temperature A rapidly rises above a certain temperature (in this case, for example, 10 ° C. or more), and then the temperature B in the washing tank (and the temperature C at the bottom of the washing tank) rises rapidly, and the evaporation of water from the inner surface of the washing tank proceeds. . At this time, since the temperature of the tableware in the washing tub has not yet risen, there is a considerable temperature difference between the tableware surface temperature and the temperature in the washing tub, so that the tableware surface gradually gets wet.
Therefore, when the room temperature suddenly rises from a low temperature to a certain temperature (for example, 10 ° C) or more, if the drying fan is operated immediately to ventilate the washing tank, the air in the washing tank with high humidity will come into contact with cold dishes and cause condensation. Therefore, the tableware surface does not get wet.

When the rate of increase in room temperature is, for example, 10 ° C./30 minutes, this cannot be a natural temperature increase, which indicates that this is a rapid indoor temperature increase due to heating.
Further, when the room temperature A naturally rises due to a change in temperature or the like, the rise is very gradual, and the temperature in the cleaning tank gradually increases following the increase in the room temperature A. A large temperature difference cannot occur with respect to the temperature B (see the temperature rise trend in FIG. 1). Therefore, when the room temperature A is higher than the reference temperature difference ΔT (for example, 5 ° C.) than the cleaning bath temperature B, it indicates that the room temperature is rapidly increasing. When the temperature in the washing tub rises by a predetermined temperature (for example, 5 ° C.) due to a rapid rise in room temperature, the tableware temperature does not increase so much, and a considerable temperature difference is generated between the temperature in the washing tub and the tableware temperature.
As described above, in the process of increasing the room temperature, when the room temperature A is higher than the cleaning bath temperature B by a reference temperature difference ΔT (for example, 5 ° C.) or more, the above condensation may soon occur. It can be regarded as being foretold.

(A) The tableware cleaned after the completion of the cleaning operation is left in the cleaning tank, (b) the room temperature T0 has decreased to the reference temperature Ts, and (c) the room temperature T0 has started to rise. temperature increases, when the short time temperature rise reference rise temperature Tu (for example, 10 ° C.) or higher in three conditions are satisfied in that the room air (cleaning tank to the cleaning tank by operating the drying fan by venting the high temperature and low humidity air) than the inner surface of the cleaning is left next morning in a cleaning tank after the end of tableware, reliably prevent the will get wet with dew.
In addition, it can replace with the said condition (c) and can also be set as the following conditions (d).
(D) The room temperature T0 is higher than the reference temperature difference ΔT by the cleaning bath temperature T1.
And since this ventilation operation does not heat and dry by operating a heater, there is little energy loss.

  It should be noted that the conditions (a), (b), and (c) are satisfied in winter when the room temperature is rapidly increased due to heating, and when the requirement (d) is satisfied, the requirement (c) is always satisfied. ) Is satisfied. Therefore, the condition (c) is indirectly confirmed by confirming the condition (d).

Next, an example in which the present invention is applied to a drawer-type dishwasher will be described with reference to the drawings.
The configuration of the dishwasher of this embodiment is not fundamentally different from the conventional one. FIG. 2 schematically shows a cross-sectional structure of the drawer-type dishwasher. A washing tub 1 is supported on a dishwasher main body (hereinafter simply referred to as “main body”) H so as to be freely inserted and removed in the front-rear direction (left-right direction in FIG. 2) by rails. There is a tableware basket 3 in the washing tub 1, and the tableware 4 is stored in the tableware basket. There is a cleaning nozzle 5 below the tableware basket 3, and this cleaning nozzle 5 is connected to a cleaning pump 6. Further, a suction pipe 10 of the cleaning pump 6 is connected to a water reservoir 11 at the bottom of the cleaning tank 1.

Water is supplied to the washing tub 1 until the water supply valve 8 of the water supply pipe 7 is opened and a predetermined water level is detected by the water level detector 22. The washing water is pressurized by the washing pump 6 under a predetermined water level, and is ejected from the washing nozzle 5 to wash the dishes. When the washing and rinsing are finished, the water is drained by the drain pump 9.
A cleaning tank temperature sensor (thermistor) 12 is provided on the wall surface of the cleaning tank 1, and the cleaning tank temperature sensor 12 detects the cleaning tank temperature when necessary. The cleaning tank temperature sensor 12 can also be used as a water temperature detection sensor (thermistor) for water in the cleaning tank.
When the rinsing process is completed, air is sent to the cleaning tank by the drying fan 20, heated by the heater 21, circulated in the cleaning tank, and finally discharged from the cleaning tank 1.
In this embodiment, an indoor temperature sensor (thermistor) 13 is provided on the outer surface of the main body H.

When a series of washing operations such as washing, rinsing, and drying are completed, the operation of the dishwasher is automatically stopped , and automatic dry operation control is started as shown in FIG. 4 (step S1) . When the door is opened after the operation is finished ( step S2), it is considered that the tableware has been taken out. If the automatic dry operation control is performed, the automatic dry operation control is stopped at that time ( step S2-1).
When the door is not opened in step S2, the indoor temperature T0 is detected by the indoor temperature sensor 13 at predetermined time intervals (for example, 3 minutes) and input to the microcomputer (control means) ( step S3). If the input room temperature T0 is compared with a reference temperature Ts (for example, 5 ° C.) and is equal to or lower than the reference temperature Ts, the process proceeds to step S5. If not below the reference temperature Ts, steps S2, S3 and S4 are repeated. In step S5, a change in room temperature (high or low with respect to the immediately preceding detected temperature) is calculated. When the change in the room temperature tends to increase, the process proceeds to step S6. If there is no upward trend, steps S2, S3, S4 and S5 are repeated.

In step S6, the cleaning tank temperature T1 is detected by the cleaning tank temperature sensor 12, and this is input to the microcomputer (control means) ( step S6). Then, the room temperature T0 is compared with the cleaning tank temperature T1, and it is determined whether the difference is higher than a reference temperature difference ΔT (for example, 5 ° C.) (step S7). If the reference temperature difference ΔT (for example, 5 ° C.) or more, the drying fan 20 is operated to ventilate the cleaning tank 1 ( step S8). If the reference temperature difference ΔT or less, steps S2 to S7 are performed at a predetermined interval (for example, 1). Repeated in minutes).
Since the operation time of the drying fan 20 is intended to ventilate the inside of the washing tank, approximately 10 minutes is sufficient. When the ventilation operation for the predetermined time is finished, the automatic dry operation is finished (step S9).

  In this example, it is indirectly confirmed that the increase in the room temperature A is a rapid increase due to heating by checking whether T0−T1> ΔT, but the room temperature increase rate is directly detected. May be. In this case, the criterion for determining the temperature rise rate may be 1.5 ° C./1 minute, and the room temperature may be detected every minute.

Since the humidity in the washing tank is sufficiently lowered by one ventilation operation, it is not always necessary to repeat the ventilation operation by the drying fan. However, since the cooling in the early morning is severe, the difference between the surface temperature of the tableware in the washing tank after the first ventilation operation and the room temperature is extremely large (for example, 10 ° C. or more), and then the room introduced into the washing tank It is not without the possibility that the air touches the tableware surface and is cooled significantly, thus causing condensation to wet the tableware surface. In such a case, it may be possible to end the process after repeating it 2-3 times intermittently at a constant time interval (for example, every 10 minutes). In such a case, if the inside of the washing tank is heated by the heater 21, the drying effect is enhanced and the ventilation operation need not be repeated.

These are figures which show the change of the temperature of each part after completion | finish of operation | movement of a dishwasher. These are sectional drawings which show typically the structure of a drawer type dishwasher. These are the block diagrams which show typically the structure of the Example of this invention. Is an operational flow diagram of an embodiment of the present invention.

Explanation of symbols

1: Washing tank 3: Tableware basket 4: Tableware 5: Washing nozzle 6: Washing pump 7: Water supply pipe 8: Water supply valve 9: Drain pump 10: Suction pipe 11: Puddle 12: Temperature sensor (thermistor) in the washing tank
13: Indoor temperature sensor (thermistor)
20: Drying fan 21: Heater 22: Water level detector

Claims (5)

In dishwashers that perform ventilation operation by operating the drying fan when the cleaned and dried dishes are stored in the washing tank,
The dishwasher includes a door open / close detection means, and includes an indoor temperature sensor.
A determination means for comparing the indoor temperature T0 and the reference temperature Ts to determine the level;
A determination means for determining that the room temperature was worth is the reference rise temperature Tu above,
After completion of the cleaning / drying operation, when the door opening / closing detection means does not detect the opening of the door, the room temperature T0 falls below the reference temperature Ts, and the room temperature rise is equal to or higher than the reference rise temperature Tu. dishwasher, characterized in that it comprises a control means for ventilating the cleaning tank by the drying fan is operated for a predetermined time. In dishwashers that perform ventilation operation by operating the drying fan when the cleaned and dried dishes are stored in the washing tank,
The dishwasher includes a door opening / closing detection means, an indoor temperature sensor, and a cleaning tank internal temperature sensor,
A determination means for comparing the indoor temperature T0 and the reference temperature Ts to determine the level;
It has a determination means the difference between the cleaning tank temperature T1 and the indoor temperature T0 (T0-T1) is to determine that greater than the reference temperature difference [Delta] T the (T0-T1> ΔT),
After the cleaning / drying operation is finished, the door temperature is not detected by the door opening / closing detection means, and the room temperature T0 falls below the reference temperature Ts, and the difference between the cleaning tank temperature T1 and the room temperature T0 (T0−T1). ) time is equal to or higher than the reference temperature difference [Delta] T, dishwasher, characterized in that it comprises a control means for ventilating the cleaning tank by the drying fan is operated for a predetermined time.   The dishwasher according to claim 1 or 2, wherein the reference temperature Ts is 5 ° C. The dishwasher according to claim 1 or 2, wherein the reference temperature rise Tu is 10 ° C.   The dishwasher according to claim 2, wherein the reference temperature difference ΔT is 5 ° C.