JPH11276411A - Dishwasher - Google Patents

Abstract

(57) [Summary] PROBLEM TO BE SOLVED: To provide a dishwasher for washing tableware by spraying water onto tableware stored in the washing tank and drying it by sending hot air, wherein the temperature in the washing tank in the drying process depends on the temperature in the washing tank. The on / off time of the heater is finely controlled to avoid a sudden rise or fall in the temperature in the cleaning tank and to keep the temperature at a substantially constant temperature, thereby improving the drying performance. A control device (13) controls a heater (6) on and off in a drying process to adjust a temperature in a cleaning tank (1). , The duty ratio at the time of temperature drop after reaching the predetermined temperature, and the duty ratio at the time of the second and subsequent heating at which the temperature drops and heats again. The three duty ratios are set so as to be from large to small in the order of the first heating, the second and subsequent heatings, and the temperature drop.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dishwasher for washing dishes by spraying water on dishes stored in a washing tank, and drying the dishes by sending warm air thereto.

[0002]

2. Description of the Related Art Conventionally, a dishwasher of this type has been configured as shown in FIG. Hereinafter, the configuration will be described.

[0003] As shown in FIG.
Is housed inside, and the washing water is stored at the bottom, and the front surface is an opening. The washing nozzle 3 is rotatably supported inside, and the washing water is ejected toward the tableware 2. The cleaning pump (cleaning means) 4 sends cleaning water to the cleaning nozzle 3 and is driven by a motor 5. Heater 6
Is disposed at the bottom of the cleaning tank 1 to heat the cleaning water.

The lid 7 covers the opening of the washing tank 1 so as to be openable and closable, and a front surface thereof is provided with a control device 8 for sequentially controlling a series of operations of washing, rinsing and drying of the dishes 2. The exhaust fan 9 is provided at the rear of the cleaning tank 1 so that the steam in the cleaning tank 1 is exhausted from an exhaust port 11 on the front surface via an exhaust duct 10. Further, the temperature detecting means 12
Is disposed at the bottom of the cleaning tank 1 so as to detect the water temperature in the cleaning tank 1 and the temperature inside the tank.

The operation of the above configuration will be described. After the user opens the lid 7 to dispose the tableware 2 and puts the detergent into the washing tank 1, the user turns on the power by the operation display unit provided in the control device 8, selects an operation course, and operates. When starting, first, a predetermined amount of tap water is supplied to the bottom of the washing tank 1 and the motor 5 and the heater 6 are energized. The washing water is spouted from the washing nozzle 3 toward the tableware 2 by the washing pump 4 while being heated. It removes dirt from the dishes. The same operation is performed in the rinsing process.

In the drying step, after rinsing water in the washing tank 1 is drained, the heater 6 is energized, and the exhaust fan 9 operates while heating the inside of the washing tank 1 so as to supply water vapor from the exhaust duct 10 to the exhaust port 11. To the outside, and the drying of the tableware 2 proceeds.

In the drying step, the controller 8 controls the heater 6 until the temperature in the cleaning tank 1 reaches a predetermined temperature T11, as shown in FIG. However, after reaching T11, the power supply was turned off, and when the temperature dropped to T12, the heater 6 was supplied with power again.

[0008]

In such a conventional structure, when controlling the temperature in the drying process, the control of the power supply to the heater 6 is only in two states, ON and OFF.
There has been a problem that the temperature in the washing tank 1 or the temperature of the tableware 2 is too high or too low, and it is difficult to obtain optimal drying performance.

The present invention has been made to solve the above-mentioned conventional problems. The temperature in the cleaning tank during the drying process is controlled in detail by controlling the ON / OFF time of the heater so that the temperature in the cleaning tank rapidly rises or falls. The purpose is to avoid and keep it at a substantially constant temperature to improve the drying performance.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a heating means for heating air in a washing tank for accommodating tableware, and discharging steam in the washing tank through an exhaust port. An exhaust fan is provided, and the temperature detected by the temperature detecting means for detecting the temperature in the cleaning tank and the temperature of the cleaning water is determined by:
The control means controls the on / off control of the heating means in the drying process to adjust the temperature in the cleaning tank, and the duty of the first on / off operation during the first heating until the temperature reaches a predetermined temperature. And three different duty ratios: a duty ratio when the temperature drops after reaching the predetermined temperature, and a duty ratio when heating after the second time when the temperature drops and heats again. Are set so as to change from large to small in the order of the first heating, the second and subsequent heatings, and the temperature drop.

[0011] Thus, the temperature in the cleaning tank during the drying process can be controlled at a substantially constant temperature by precisely controlling the ON / OFF time of the heater so as to avoid a rapid rise or fall in the temperature inside the cleaning tank. And drying performance can be improved.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to claim 1 of the present invention is directed to a washing tank for accommodating dishes, a washing nozzle for jetting washing water toward the dishes, and a washing tank stored in the washing tank. Cleaning means for feeding water to the cleaning nozzle; heating means for heating the cleaning water and air in the cleaning tank; an exhaust fan for discharging water vapor in the cleaning tank through an exhaust port; Temperature control means for detecting a water temperature of water, and control means for sequentially controlling a series of operations of washing, rinsing, and drying of the dishes, wherein the control means turns on and off the heating means in the drying step. Controlling the temperature in the cleaning tank, the duty ratio of ON / OFF at the time of the first heating until reaching the predetermined temperature, and the temperature drop after reaching the predetermined temperature. The duty ratio and the temperature drops again It has three different duty ratios of the duty ratio at the time of heating from the second heating onward, and the three duty ratios are changed from the largest at the time of the first heating, at the time of the second heating, and at the time of the temperature drop. It is set to be small, the largest power is given to the heating means at the time of the first heating, the smallest power is given at the time of temperature drop, and the intermediate power is given at the time of the second and subsequent heatings,
The inside of the washing tank can be maintained at a substantially constant temperature, and the drying performance can be improved.

According to a second aspect of the present invention, in the first aspect of the invention, the control means sets the upper limit temperature to a temperature higher than a predetermined temperature. When the temperature reaches the upper limit, the heating means is completely turned off.After reaching a predetermined temperature, even if the temperature continues to rise even when the power of the heating means is minimized, Drying can be controlled without damaging tableware.

According to a third aspect of the present invention, in the first aspect of the present invention, the control means sets the three different duty ratios so that the period from one on to the next on is constant and only the duty ratio is changed. By making the ON / OFF cycle constant, the program configuration when the control means is configured by a microcomputer is simplified, and the number of ON / OFF times of the relay for turning ON / OFF the heating means. And the drying performance can be improved, and the reliability of the control means can be improved.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. Note that the arrangement of each component is the same as that shown in FIG. 5, and a description thereof will be omitted.

(Embodiment 1) As shown in FIG. 1, a control device (control means) 13 controls a heater (heating means) on and off in a drying process to adjust the temperature in the cleaning tank 1; On / off duty ratio (ratio of ON time) at the first heating until reaching a predetermined temperature (temperature control temperature) and duty at the time of temperature drop after reaching the predetermined temperature Ratio and the second the temperature drops and reheats
It has three different duty ratios of the duty ratio at the time of the subsequent heating, and these three duty ratios are changed from large to small in the order of the first heating, the second and subsequent heating, and the temperature drop. It is set as follows. Other configurations are the same as the conventional example.

The operation of the above configuration will be described. FIG.
Represents the temperature change in the cleaning tank 1 during the drying process,
1, T2 is a predetermined temperature (temperature controlled)
In the drying process, the temperature is raised in the shortest possible time with the first temperature gradient ΔT1. However, since the continuous energization has an adverse effect on the life of the heater 6, the heater 6 is energized at the first duty ratio shown in FIG.

When the temperature reaches a predetermined temperature T1, as shown in FIG. 3 (b), the ratio of the ON time is greatly reduced to prevent the temperature from rising further, and the heater 6 is turned on at the second duty ratio. Turn on electricity. Therefore, the behavior shown by the temperature gradient ΔT2 in FIG. 2 is obtained. If you turn it off completely at this time,
Since the temperature may be too low and the drying performance may be degraded, the duty ratio is lowered.

When the temperature drops to T2, the temperature is raised again. As shown in FIG. 3 (c), when the ratio of the ON time is increased and the heater 6 is energized at the third duty ratio, as shown in FIG. The temperature starts to rise as in the temperature gradient ΔT3. At this time, the duty ratio of the ON time is set to be smaller than the first duty ratio and larger than the second duty ratio because the temperature in the cleaning tank 1 has already been increased to some extent.

The reason for this is that if the duty ratio is the same as the first duty ratio, the temperature immediately reaches the predetermined temperature T1 and the duty ratio falls, so that this is avoided and the heating state is maintained for as long as possible. This is for keeping the temperature in the cleaning tank 1 as constant as possible.

After the temperature rises with the temperature gradient ΔT3 in FIG. 2 and reaches the predetermined temperature T1 again, the second duty ratio in FIG. 3B and the third duty ratio in FIG. By repeating the ratio, the temperature gradients ΔT2 and ΔT3 of FIG. 2 are repeated, and a substantially constant temperature between the predetermined temperatures T1 and T2 can be maintained, and the drying performance can be optimized.

(Embodiment 2) The control device (control means) of FIG.
Reference numeral 13 is configured to set the upper limit temperature to a temperature higher than a predetermined temperature, and to completely turn off the heater 6 when the temperature in the cleaning tank 1 reaches the upper limit temperature.
Other configurations are the same as those in the first embodiment.

The operation of the above configuration will be described. FIG.
Represents the temperature change in the cleaning tank 1 during the drying process,
1, T2 is a predetermined temperature (temperature controlled)
After the temperature reaches the predetermined temperature T1, even if the duty ratio of the on-time is reduced, the temperature in the cleaning tank 1 does not decrease as in the case of FIG. is there.

In this case, the temperature gradient is set to ΔT4 in FIG.
A temperature T3 higher than the predetermined temperature T1 is set, and when the temperature T3 has been reached, the heater 6
Turn off the power to the switch completely. As a result, the temperature drops sharply at the temperature gradient ΔT5 in FIG. 4, and after the temperature drops to T2 after passing through T1, the same control as in the first embodiment is performed.

As a result, it is possible to prevent the temperature in the washing tank 1 and the temperature of the tableware 2 from rising excessively even if the conditions such as the ambient temperature fluctuate, and to improve the drying performance while ensuring safety. Can be.

(Embodiment 3) The control device (control means) of FIG.
No. 13 sets three different duty ratios so that the period from one ON to the next ON is constant, and only the duty ratio is changed. Other configurations are the same as those in the first or second embodiment.

The operation of the above configuration will be described. FIG.
5A shows the duty ratio of the ON time of energization to the heater 6, and the first duty ratio shown in FIG. 5A corresponds to the first heating, and the second duty ratio shown in FIG. Is the time of temperature drop, and the third duty ratio shown in FIG. 5C is the time of the second or subsequent heating.

All of these duty ratios are set at the same cycle (60 seconds in this case), with the first duty ratio being on 25 seconds and off 35 seconds, and the second duty ratio being on 14 seconds and off 46. The second duty ratio is 20 seconds on and 40 seconds off at the third duty ratio.

By making the cycle the same as described above,
The program in the case of control by the microcomputer can be simplified, and the reliability of the control device 13 is improved by keeping the number of times of ON / OFF of the relay for controlling ON / OFF of the heater 6 to improve the drying performance. Can be improved.

[0030]

As described above, according to the first aspect of the present invention, the washing tank for storing the dishes, the washing nozzle for jetting the washing water toward the dishes, and the washing tank are provided. Cleaning means for feeding the stored cleaning water to the cleaning nozzle, heating means for heating the cleaning water and the air in the cleaning tank, and an exhaust fan for discharging water vapor in the cleaning tank through an exhaust port,
Temperature detecting means for detecting the temperature in the washing tank and the temperature of the washing water, and washing means for rinsing, rinsing, control means for sequentially controlling a series of operations in a drying step, the control means in the drying step On / off control of the heating means to adjust the temperature in the cleaning tank, the duty ratio of on-off at the first heating until reaching a predetermined temperature, and the predetermined temperature It has three different duty ratios, that is, a duty ratio at the time of temperature decrease after reaching the temperature and a duty ratio at the time of second and subsequent heating in which the temperature is lowered and heating is performed again. Time,
Since the temperature is set to be large to small at the time of the second and subsequent heating and temperature drop, the largest power is given to the heating means at the time of the first heating, and the smallest power is given at the time of temperature drop. During the subsequent heating, an intermediate power is given to keep the inside of the cleaning tank at a substantially constant temperature, and the drying performance can be improved.

According to the second aspect of the present invention, the control means sets the upper limit temperature to a temperature higher than a predetermined temperature, and the temperature in the cleaning tank reaches the upper limit temperature. In this case, since the heating means is completely turned off, even after the temperature reaches a predetermined temperature, even if the temperature continues to rise even if the power of the heating means is minimized, without damaging tableware Drying can be controlled.

According to the third aspect of the present invention, the control means sets three different duty ratios so that the period from one on to the next on is constant and only the duty ratio is changed. Therefore, by making the on / off cycle constant, the configuration of the program when the control means is constituted by a microcomputer is simplified, and the number of times the relay for turning on and off the heating means is turned on and off can be made constant, and the drying performance can be improved. And the reliability of the control means can be improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a dishwasher according to a first embodiment of the present invention.

FIG. 2 is a time chart showing changes in the temperature in the washing tank of the dishwasher / dryer.

FIG. 3 is a time chart showing a duty ratio of heater energization of the dishwasher.

FIG. 4 is a time chart showing changes in the temperature in the washing tank of the dishwasher according to the second embodiment of the present invention.

FIG. 5 is a time chart showing a duty ratio of heater energization of a dishwasher according to a third embodiment of the present invention.

FIG. 6 is a sectional view of a conventional dishwasher and dryer.

FIG. 7 is a time chart showing changes in the temperature in the washing tank of the dishwasher;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Washing tank 2 Tableware 3 Washing nozzle 4 Washing pump (washing means) 6 Heater (heating means) 9 Exhaust fan 11 Exhaust port 12 Temperature detecting means 13 Control device (Control means)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Takashi Miyauchi 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A washing tank for accommodating tableware, a washing nozzle for jetting washing water toward the tableware, washing means for feeding washing water stored in the washing tank to the washing nozzle, washing water and washing Heating means for heating the air in the tank, and an exhaust fan for discharging steam in the cleaning tank through an exhaust port,
Temperature detecting means for detecting the temperature in the washing tank and the water temperature of the washing water; and a control means for sequentially controlling a series of operations of the washing, rinsing, and drying steps of the dishes, wherein the control means includes: On / off control of the heating means to adjust the temperature in the cleaning tank, the duty ratio of on / off at the first heating until reaching a predetermined temperature, and the predetermined temperature. It has three different duty ratios, that is, a duty ratio at the time of temperature decrease after the temperature has reached, and a duty ratio at the time of the second and subsequent heating in which the temperature is lowered and heated again. Time,
Dishwasher / dryer set from the largest to the smallest in order of heating and temperature drop after the second time. 2. The control means sets an upper limit temperature to a temperature higher than a predetermined temperature, and completely turns off the heating means when the temperature in the cleaning tank reaches the upper limit temperature. The dishwasher / dryer according to claim 1 configured as described above. 3. The control means sets the three different duty ratios so that a period from one on to the next is constant.
2. The dishwasher according to claim 1, wherein only the duty ratio is changed.