JPH06105787A - Dish washing and drying machine - Google Patents

Abstract

PURPOSE:To protect against abnormal overheat condition certainly by performing failure sensing using a temp. sensing means for monitoring the internal temp. of a washing tub, and performing protective operations. CONSTITUTION:A control circuit of a dish washing/drying machine executes the error countermeasure associate with a heater 16 at regular intervals. That is, an output signal is issued to turn off the heater 16, washing pump 11, dosing devices 17, 18, and a water supply solenoid valve 31 if the sensing temp. Th3 given by a temp. sensing element 3 exceeds the first stage failure temp. TH3EW for inside the tub (80 deg.C) in the wash and rinse process or exceeds the first stage failure temp. TH3ED for inside the tub (90 deg.C) in the drying process, or if the sensing temp. Th2 given by a temp. sensing element 2 installed on the exterior wall of the wash tub 10 has exceeded the first stage failure temp. TH2EW for outside the tub (75 deg.C) in the rinse process, and also a water exhaust pump 12 is operated for a specified time (25 sec) to perform draining, and a buzzer is actuated while error output is indicated on a display means to exhibit a failure in the heater.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dishwasher / dryer, and more particularly to a protection circuit against abnormal temperature rise.

[0002]

2. Description of the Related Art A dish washer / dryer has a washing and rinsing step for removing the stains on the dishes which are heated by a heater and sprayed with water sprayed from a nozzle into the washing bath. After discharging the water, the dishes are washed and dried from the drying step of heating the inside of the washing tank with the heater, but the temperature control of the hot water in the washing and rinsing steps and the temperature control in the washing tank during the drying step are Generally, the temperature detected by a temperature detecting means such as a thermistor is compared with a preset temperature, and if it exceeds a certain temperature, the relay Ry connected in series to the heater 16 is turned off as shown in FIG. By doing so, the power supply to the heater 16 is stopped. In the figure, S is a shut-off unit for automatic power-off, which is automatically shut off when the washing / drying process of tableware is completed.

[0003]

In this case, the heater 16 cannot be turned off due to contact welding of the relay Ry, failure of the relay drive circuit, etc., and the temperature inside the cleaning tank becomes abnormal. The fuse F is inserted into the power supply circuit in the case of rising, but the temperature in the cleaning tank rises considerably before the fuse F melts, so the cleaning tank is made of synthetic resin. In some cases, it may be deformed or discolored by heat. Further, when the fuse F is blown, the fuse F must be replaced, but if the dishwasher is built in the system kitchen, the replacement work becomes difficult. There is a bimetal switch inserted in the power supply circuit for automatic recovery, but even in this case, there is a high possibility that the temperature in the cleaning tank will rise considerably before the shutoff by the bimetal switch. If the abnormal state continues after the return of the, the power supply to the heater will be restarted until it becomes overheated.Since this state is repeated thereafter, the heat load on the cleaning tank becomes extremely large. I will end up.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a dishwasher / dryer capable of early detection of an abnormal overheated state and surely performing protection. is there.

[0005]

SUMMARY OF THE INVENTION The present invention, however, comprises a heating means for heating the inside of the cleaning tank and a temperature detecting means for detecting the temperature in the cleaning tank, and the temperature detecting means performs the cleaning by the heating means. In a dishwasher / dryer for controlling the temperature of heating in the tank, a warning of an abnormal state and a cutoff unit for controlling the heater are activated by the first-stage abnormal temperature detection by the temperature detecting means for controlling the temperature in the cleaning tank. It is characterized in that it is provided with a protection circuit that outputs an output to cause an electromagnetic shutoff unit different from the shutoff unit for controlling the heater to be shut off when the second stage abnormal temperature higher than the first stage abnormal temperature is detected. .

[0006]

According to the present invention, since the abnormality is detected by using the temperature detecting means for monitoring the temperature in the cleaning tank, the abnormality can be detected more accurately and early, and the abnormality can be detected in two stages. In addition, it is safe to perform the protective operation, and since it is cut off by the electromagnetic cutoff portion, it is easy to restore.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the illustrated embodiments. As shown in FIG. 3, this dishwasher / dryer has a washing tank 10, a washing pump 11, a drainage pump 12, a fixed nozzle 13, It is equipped with spray nozzles 14 and 15, a heater 16 and the like, and dishes are set in the cleaning tank 10, and a special detergent and a dry finishing agent are set in the detergent feeding device 17 and the finishing agent feeding device 18, respectively. After that, when the door is closed, the door switch 21 is turned on and the preparation for operation is completed. In this state, the control circuit power switch 22 of the operation panel is turned on, and the start switch 23 is pressed to wash and dry in the standard mode. Is started.

That is, when the drainage pump 12 first operates to drain water until the normal water level detecting pressure switch 19 is turned off, then the water supply solenoid valve 31 is turned on and the water supply into the cleaning tank 10 is started. When the normal water level detection pressure switch 19 is turned on, the water supply solenoid valve 31 is closed and the water supply process is completed. After that, the cleaning pump 11 is operated, the heater 16 is energized, and the detergent throwing device 17 throws in the detergent. The washing water pressurized by the washing pump 11 is fixed nozzle 13 and spray nozzle 14. ，
15 is sprayed from the spray nozzles 14 and 15 at this time.
Rotates by the spray pressure and applies cleaning water to every corner of the tableware. The cleaning water sprayed from the nozzles 13, 14, 15
After being filtered by the filter 32, it returns to the washing pump 11. The cleaning process in which the cleaning water is sprayed in this way is continued for a predetermined time, and during this time, the temperature of the heater 16 is controlled so as to maintain a set temperature (for example, 60 ° C.).

After the cleaning process is completed, the water is once drained and then water is supplied again, and the nozzles 13 and 1 are connected.
A rinsing step of injecting water from 4, 15 is performed, and drainage is performed after a predetermined time. This rinsing step is repeated a plurality of times, and in the final rinsing step, rinsing is performed by the hot water heated by the heater 16, the dry finishing agent is added immediately before the completion of the hot water rinsing, and then the drainage is performed.

Next, in the drying process, a control circuit consisting of a microcomputer that controls the operation of the dishwasher / dryer is washed by a temperature detecting element 2 such as a thermistor mounted on the outer wall surface of the washing tank 10. Tank 10
Based on the temperature comparison between the temperature Th2 in the cleaning tank 10 detected through the wall of the heater and preset temperatures T1, T2 and T3, the energization of the heater 16 is controlled until the temperature reaches the predetermined temperature T1. Performs energization with a duty ratio having a long on-time (here, energization of intervals in which on and off are repeated at predetermined time intervals), and a predetermined temperature T
When the value exceeds 1, the energization is performed with a duty ratio having a short ON time, and when the set temperature T2 or T3 is reached, the energization to the heater 16 is cut off. It should be noted that the duty ratio control is generally because the heater also serves to heat the wash water, but since the heat conduction of air is smaller than that of water,
This is because if electricity is constantly applied for drying, the area around the heater becomes too hot and the temperature distribution in the cleaning tank greatly varies.

That is, the control circuit controls the operation of the heater 16 based on the flowcharts shown in FIGS. 4 and 5 as a subroutine for the drying step. When entering, the drying timer is turned on, the initial flag is 0,
After performing the initial setting with the heater on flag set to 1,
Temperature Th2 in the cleaning tank 10 detected by the temperature detection element 2
Is compared with a predetermined temperature T1 (for example, 65 ° C.), and when the temperature is equal to or lower than the predetermined temperature T1, the initial flag is set to 1, and the on-time t1 (for example, 18 seconds) set by the on-timer and the off-timer are set. The heater 16 is energized with the interval energization for the set off time (for example, 20 seconds). If the detected temperature Th2 exceeds the predetermined temperature T1, as shown in FIG. 5, when the initial flag is 1, the detected temperature Th2 is compared with the set temperature T2 (for example, 78 ° C.), and the initial flag is 0. Sometimes the detected temperature Th
2 is compared with the set temperature T3 (for example, 80 ° C.), and if the set temperatures are T2 and T3 or less, the on-time t2 (for example, 12 seconds) set by the on-timer and the off-time set by the off-timer. When the heater 16 is energized at intervals of (for example, 20 seconds) and the detected temperature Th2 reaches the set temperatures T2 and T3, the energization of the heater 16 is cut off and the initial flag is set to zero.

Until the temperature in the cleaning tank 10 reaches the predetermined temperature T1, the heater 16 is energized with a duty ratio having a long ON time so that the temperature rises quickly and reaches the predetermined temperature T1. For example, by energizing with a duty ratio having a short on-time, overshoot is less likely to occur. Further, when heating is started from a state where the detected temperature Th2 is equal to or lower than the predetermined temperature T1, the heater 16 By setting the set temperature at which the power supply to the power supply is cut off to a temperature T2 lower than the set temperature T3 for the subsequent power supply cutoff, it is possible to more reliably prevent overshoot at the start of heating at which overshoot most easily occurs. There is something.

It is to be noted that when the interval energized state is switched to the cutoff state, the off state is maintained for a required off holding time and then the interval energized state is allowed to be allowed. The chattering operation is prevented by keeping the ON state for the required ON holding time. The temperature detecting element 2 attached to the outer wall surface of the cleaning tank 10 is used in the drying step because when the temperature detecting element is arranged in the cleaning tank 10, it is used in the cleaning step and the rinsing step performed before the drying step. This is because the temperature inside the cleaning tank 10 cannot be accurately detected if the temperature detecting element is wet with the water. The water temperature detection for controlling the temperature of the water in the cleaning process and the rinsing process is performed by the temperature detection element 3 arranged in the cleaning tank 10.

The control circuit of this dishwasher / dryer is
As a countermeasure against the error related to the heater 16, the subroutine shown in FIGS. 1 and 2 is periodically executed by a time interrupt or the like. That is, the temperature Th3 detected by the temperature detecting element 3
However, in the cleaning and rinsing process, the first stage abnormal temperature T for the tank
H3EW (eg, 80 ° C.) is exceeded, or the first-stage abnormal temperature TH3ED (eg, 90 ° C.) for the tank in the drying process.
℃) or the detected temperature Th2 by the temperature detecting element 2 arranged on the outer wall of the cleaning tank 10 is the outside first tank abnormal temperature TH2EW (for example, 7) in the cleaning and rinsing step.
5 ° C.) or when the temperature exceeds the outside first tank abnormal temperature TH2ED (for example, 85 ° C.) in the drying process, as shown in FIG. 2 (a), the heater 16, the cleaning pump 11, the injector 17, 18 and the water supply solenoid valve 31 are turned off, and the drainage pump 12 is operated for a predetermined time (for example, 25 seconds) to drain the water, and a buzzer sounds to notify and an error output display indicating a heater abnormality on the display means. I do.

When the relay 16 for controlling the heater 16 shown in FIG. 6 is not turned off in response to the output from the control circuit for turning off the heater 16 at this time, the temperature further rises. , The temperature Th3 detected by the temperature detecting element 3 is the second-stage abnormal temperature TH3P for the tank (for example, 1
Temperature of 100 ° C or the temperature T detected by the temperature detection element 2
When h2 exceeds the outside tank second-stage abnormal temperature TH2P, as shown in FIG. 2 (b), the heater 16 and the cleaning pump 1
1, an output for turning off the drainage pump 12, the injectors 17 and 18, and the water supply solenoid valve 31 is output to give a notification by a buzzer sound and an error output display indicating a heater abnormality to the display means, and shut off for automatic power off. By turning off the part S, the power supply to the heater 16 is cut off.

Since the abnormal temperature is detected by using the outputs of the temperature detecting elements 2 and 3 for controlling the temperature of hot water in the washing and rinsing step and controlling the temperature in the tank in the drying step, the response to overheating is high. It is excellent, and since the operation of cutting off the energization to the heater 16 is performed in two steps, the reliability is also high. Further, since the interruption is performed by the electromagnetic interruption, there is no need for a difficult recovery work as in the case where the fuse F is blown.

It should be noted that the reason why the abnormal temperature to be shifted to the abnormality detecting operation in the washing and rinsing step and the drying step is made different is to enable more accurate abnormality detection, and the inside of the cleaning tank 10 is to be detected. The temperature detecting element 3 arranged and the temperature detecting element 2 arranged outside the cleaning tank 10 are used to reduce the influence of damage to the temperature detecting elements 2 and 3. Further, in the above-mentioned embodiment, the cut-off portion S for automatic power-off is also used for the cut-off for abnormal condition.
It goes without saying that a relay R dedicated to the abnormal shutoff may be inserted in series with the heater 16 and the relay Ry as shown in FIG. 3 to shut off the relay R when the second stage abnormality occurs.

[0018]

As described above, according to the present invention, in order to detect an abnormality using the temperature detecting means for monitoring the temperature in the cleaning tank, the abnormality can be detected more accurately and early and the heater can be detected. It is possible to cut off the energization, and moreover, it is safer because it performs abnormality detection and protection operation in two steps and operates different breaking sections in both steps. It is easy to restore because of the above.

[Brief description of drawings]

FIG. 1 is a flowchart showing an operation at the time of abnormality in one embodiment.

2 (a) and 2 (b) are flowcharts showing an operation at the time of abnormality in the same as above.

FIG. 3 is a schematic sectional view.

FIG. 4 is a flowchart showing an operation in one embodiment.

FIG. 5 is a flowchart showing an operation of the above.

FIG. 6 is a circuit diagram of the same as above.

FIG. 7 is a circuit diagram of another embodiment.

FIG. 8 is a circuit diagram of a conventional example.

[Explanation of symbols]

 2 Temperature detection element 10 Cleaning tank 16 Heater

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mitsunori Teramoto 1-52-1 Oka Minami-shi Minato-ku Osaka City Harman Co., Ltd.

Claims (4)

[Claims] 1. A tableware comprising a heating means for heating the inside of the cleaning tank and a temperature detecting means for detecting the temperature inside the cleaning tank, and the temperature detecting means controls the temperature of heating in the cleaning tank by the heating means. In the washer / dryer, when the temperature detecting means for controlling the temperature in the cleaning tank detects the abnormal temperature in the first stage, an abnormal state warning and an output for activating the shutoff unit for controlling the heater are output, and the abnormal condition in the first stage is detected. A dishwasher / dryer, which is provided with a protection circuit that shuts off an electromagnetic shutoff unit different from a shutoff unit for controlling a heater when a second stage abnormal temperature higher than the temperature is detected. 2. The dishwasher / dryer according to claim 1, wherein the electromagnetic shutoff unit is a relay shutoff unit for automatic power-off that is shut off at the end of automatic washing / drying. 3. The dishwasher / dryer according to claim 1, wherein the first-stage abnormal temperature and the second-stage abnormal temperature are different in the washing and rinsing step and the drying step. 4. The dishwasher / dryer according to claim 1, wherein as the temperature detecting means, a temperature detecting means arranged in the washing tank and a temperature detecting means arranged on the outer wall surface of the washing tank are used. .