JPH02305599A - Clothe dryer - Google Patents

Abstract

PURPOSE:To detect choking of a filter by providing a filter choke detecting means which decides that choking of a filter occurs when a difference between the detecting temperature of a first temperature detecting means mounted to the inner wall of the door of a drying chamber and the detecting temperature of a second temperature detecting means mounted on the upper stream side of the position of a heater exceeds a given value. CONSTITUTION:When a lint filter 6c is choked, the passage of circulating air is worsened, and an airflow passing through a self-heat generating heater 7c is also reduced. As a result, the temperature of the self-heat-generating heater 7c is increased, the temperature of a door 5 is increased due to blow of hot blast discharged through an outlet 7b and transmission of heat through a casing 1. Since, with the increase in the temperature of the self-heat generating heater 7c, resistance is increased and a calorific value is decreased, a quantity of heat imparted on circulating air is also decreased, and the temperature of the outlet of a drum 6 and temperature in a circulating duct 7 are reduced. Thereby, a difference between temperature detected by a thermistor 10c and temperatures detected by thermistor 10a and 10b is in. creased. Thus, through detection of the temperature difference, worsening of the passage of circulating air can be detected.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a clothes dryer that heats air circulating within a drying chamber using a self-heating heater having a positive resistance-temperature characteristic.

<Conventional technology> Conventionally, after setting the drying time according to the amount of clothes taken into the drying chamber, a fan is rotated to circulate the air in the drying chamber through a circulation duct, and the circulating air is attached to the outlet of the circulation duct. Clothes dryers have been provided that dry clothes by heating them with a self-heating heater and sending the hot air into a drying chamber to exchange heat with clothes stored in the drying chamber.

In the above-mentioned clothes dryer, a filter is installed in the circulating air flow path to remove lint, etc. from clothes.The method for detecting clogging of this filter is to detect the current value of the self-heating heater, A current detection method (see Japanese Patent Publication No. 59-41102) that detects the clogged filter of a clothes dryer when the current value exceeds a predetermined value; There is a heater outlet temperature detection method that detects filter clogging when the difference between the hot air temperature and the ambient temperature exceeds a predetermined value.
7-96699).

<Problems to be Solved by the Invention> However, in the current detection method (2), there are variations in the characteristics of the self-heating heater, and depending on the self-heating heater, the difference between the current value and the above-mentioned predetermined value becomes small. There is a risk that "filter clogging" may be detected even if the filter is not clogged at all. Therefore, in order to set the same threshold value for all products, the detection level must be set quite low, which poses a problem that the clogging detection accuracy decreases. Although it is possible to improve clogging detection accuracy by setting the threshold value for each individual product, it is inconvenient that adjusting the threshold value for each mass-produced product requires a great deal of effort. be.

In addition, in the above heater outlet temperature detection method (2), since the temperature detector is placed immediately near the self-heating heater, it is affected by variations in the plurality of self-heating heaters connected in parallel. Furthermore, since filter clogging is detected based on the difference between the temperature of the hot air and the ambient temperature, correction based on the ambient temperature is required. Therefore, like the method (2) above, this method has the disadvantage that the detection level must be set quite low.

Furthermore, there is a demand for detecting the amount of clothes stored in the drying chamber, that is, the load amount, and automatically performing drying control according to the load amount.

The present invention has been made in view of the above problems, and provides a clothes dryer that can detect filter clogging without reducing filter clogging detection accuracy even if there are variations in the characteristics of self-heating heaters. The purpose is to

Another object of the present invention is to provide a clothes dryer that can detect the load amount and automatically perform drying control.

Means for Solving the Problems and Effects> In order to achieve the above object, the clothes dryer of the first invention has a first temperature detection means attached to the inner wall of the door that covers the drying chamber, and A second temperature detection means is installed in the duct upstream of the installation position of the self-heating heater, and the temperature detected by the first temperature detection means and the temperature detected by the second temperature detection means are and filter clogging detection means that determines that the filter is clogged when the difference exceeds a predetermined value.

In the invention with the above configuration, the inventor of the present invention measured the temperature at the door and the temperature inside the circulation duct, and found that if the filter became clogged, the difference between the temperature at the door and the temperature inside the circulation duct would become large. This was done by focusing on the phenomenon. From the above results, it is determined that the filter is clogged when the difference between the door temperature detected by the first temperature detection means and the air temperature in the circulation duct detected by the second temperature detection means exceeds a predetermined value. It can be done. In this way, by taking the difference between the door temperature and the air temperature in the circulation duct, it is possible to detect the temperature based on the temperature difference between the circulating hot air without detecting the temperature of the self-heating heater itself. Therefore, there is no need to consider variations in the self-heating heater. Furthermore, by taking the difference between the temperatures detected by the temperature detection means, the ambient temperature can be subtracted, so it is possible to eliminate errors caused by the influence of the ambient temperature.

Further, in the second invention, a third temperature detection means is attached to the entrance of the circulation duct together with the first temperature detection means, and the temperature detected by the third temperature detection means and the first temperature The apparatus includes a load amount detection means for detecting the load amount according to the difference from the temperature detected by the detection means, and a drying condition setting means for setting the drying conditions according to the load amount.

In the above invention, as a result of the inventor's measurement of the temperature at the door and the temperature at the inlet of the circulation duct, when the load is small, the temperature at the inlet of the circulation duct is higher than the temperature at the door, and the temperature increases in proportion to the increase in the load. This was done by focusing on the phenomenon that the temperature at the door increases, the temperature at the circulation duct inlet decreases, and the two temperatures are reversed.

From this result, the load amount can be determined by detecting the difference between the temperature detected by the first temperature detection means attached to the door and the temperature detected by the third temperature detection means attached to the circulation duct. can be detected. Then, by setting the drying conditions according to the load amount,
Can dry clothes properly.

<Example> Hereinafter, the clothes dryer of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a sectional view showing an embodiment of the clothes dryer.

Reference numeral 1 denotes a casing, and the casing 1 is provided with an outside air intake 2 at the rear, an exhaust hole 3 at the rear lower part, and a drain port 4 at the bottom.

Further, a door 5 is attached to the front surface of the housing 1. Inside the housing 1, a substantially cylindrical drum 6 is provided.
A fan chamber 8 housing a double-sided fan 8a is communicated with the rear of the fan chamber 8.

Further, below the drum 6, the circulation duct 7 communicates with the fan chamber 8 through the inlet lower a, and communicates with the drum 6 through the outlet lower b.
A circulation duct 7 communicating with the drum 6 is provided, and a motor storage chamber 9 containing a motor 9a is provided adjacent to the drum 6.

The motor 9a arranged in the motor chamber 9 is connected to the drum 6.
and a double-sided fan 8a, which is connected to the double-sided fan 8a by belts 9b and 9C, respectively, and is arranged in the fan chamber 8.
sucks the air in the drum 6 and supplies it to the circulation duct 7, so the air in the drum 6 circulates through the circulation duct 7 as the fan 8a rotates. Also, by rotating the double-sided fan 8a, outside air is sucked in from the outside air intake port 2.

Further, a filter accommodating portion 6a is provided at the rear inside the drum 6, and a filter cover 6b and a lint filter 6C are detachably attached to this filter accommodating portion 6a.

A self-heating heater 7C is installed at the outlet lower b of the circulation duct 7.
is attached so as to be able to come into contact with the air flowing through the circulation duct 7. This self-heating heater 7C has a positive resistance-temperature characteristic, and the amount of heat generated increases as the amount of air flowing through the circulation duct 7 increases, and decreases as the amount of air flows decreases.

Thermistors 10a, 10b, and 10c are installed at the inlet lower a of the circulation duct 7, the outlet lower b of the circulation duct 7, and the small storage chamber 5a formed inside the door 5, respectively.
or installed.

FIG. 1 is a control circuit diagram of the clothes dryer shown in FIG. 2. FIG. In the figure, thermistors 10a and 10b.

A 10c1 key input circuit 11, a reset circuit 12, a heater drive circuit 13, a motor drive circuit 14, a display 15, and a buzzer 16 are connected to a microcomputer 17. The self-heating heater 7c is connected to the heater drive circuit 13, and the motor 9a is connected to the motor drive circuit 14. The above thermistors 10a, 10b, 10
c detects the temperature at each mounting position, or it is possible to use a temperature element such as a thermocouple in addition to a thermistor.

The operation of the clothes dryer having the above configuration is as follows.

After the clothes are stored in the circulation duct 7, when the key is manually operated, the microcomputer 17 controls the heater drive circuit 13 and the motor drive circuit 14. When the motor 9a rotates, the drum 6 also rotates via the heald 9b. At the same time, the double-sided fan 8a rotates via the belt 9c.

When the double-sided fan 8a rotates, the hot air heated by the self-heating heater 7C is fed into the drum 6 from the output lower b, where it exchanges heat with the clothes and becomes hot and humid air, filter cover 6b1 lint filter 5c. , circulates through the circulation duct 7 and is heated again by the self-heating heater 7c.

On the other hand, cooling air is supplied to the outside air intake 2 by a double-sided fan 8a.
Air is taken into the fan chamber 8, cools one side of the double-sided fan 8a, and after cooling is discharged from the exhaust hole 3.

Therefore, the hot and humid air on the circulation side of the double-sided fan 8a is cooled, so that the moisture contained in the clothes is recondensed from steam and becomes water droplets. These water droplets are blown away by the double-sided fan 8a and drained out of the machine through the drain port 4 at the bottom of the housing 1.

Next, the clogging detection operation of the filter 6C will be explained based on FIG. 3.

FIG. 3 shows temperature curves when the filter is normal and when the filter is clogged at rated load.

When the filter 6c is clogged, the difference in temperature detected by the thermistor 10c and thermistor 10b increases as shown in the graph (see FIG. 3). Therefore, both thermistors 10c, 1
If the difference between the detected temperatures at 0b is greater than or equal to a predetermined value, it is determined that there is clogging.

To explain in more detail, if the lint filter 6c is clogged, the passage of circulating air becomes difficult, and the self-heating heater 7c
The amount of air passing through will also be reduced. As a result, the temperature of the self-heating heater 7c rises, and the temperature of the door 5 rises due to the blowing of hot air from the outlet lower b and heat conduction through the casing 1. When the temperature of the self-heating heater 7c rises, the resistance increases and the amount of heat generated decreases, so the amount of heat received by the circulating air also decreases, and the temperature at the outlet of the drum 6 and the temperature inside the circulation duct 7 decrease. Therefore, the temperature at the entrance lower a of the circulation duct 7 is low, but the temperature at the door 5 and its vicinity is high, and the difference between the temperature detected by the thermistor 10c and the temperature detected by the thermistor 10a and thermistor 10b. (However, thermistor 1
The temperature at 0a is easily influenced by the amount of load and cannot be used as a standard for clogging detection). Therefore, by detecting the temperature difference, it is possible to detect that the flow of circulating air has become poor.

Note that in the above case, both thermistor 10c and thermistor 10b are affected by the ambient temperature, but the ambient temperature can be canceled by taking the difference between the detected temperatures of thermistor 10c and thermistor 10b. Clogging can be detected regardless of the ambient temperature.

Further, the temperature difference between the thermistor 10c and thermistor 10b will not become large unless the following conditions are met: the temperature of the lower outlet b is high, the amount of heat generated by the self-heating heater 7c is small, and the amount of circulating air is reduced.

Therefore, even if there is some variation in the self-heating heater 7c and the temperature of the output lower b changes somewhat, the temperature difference will not be affected. Therefore, for any product, the detection level can be kept constant, and the threshold value can be set higher to bring it closer to the actual clogging level. Therefore, accuracy can be improved compared to conventional detection methods.

Next, the load amount detection operation will be explained based on FIG. 4.

FIG. 4 shows temperature curves at a small load and at a rated load. In the case of a small load, the temperatures of thermistor 10a and thermistor 10c are reversed, as shown by the solid line in the figure, and the temperature of thermistor 10a becomes higher.

This is because when the amount of load decreases, the amount of hot air passing through the clothes and being discharged from the outlet of the drum 6 increases, so the temperature of the thermistor 10H increases. On the other hand, unlike when the filter is clogged, the circulating air volume decreases and the temperature of the outlet lower b does not rise, so the thermistor 10c
temperature does not rise. As a result, the temperature relationship is reversed.

As the load amount increases, the temperature of the thermistor 10a decreases, and the temperature of the thermistor 10c increases.

Furthermore, when the load amount is greater than the rated value, only the value of the thermistor 10c becomes higher than the rated value.

This is because the amount of load is abnormally large, making it difficult for circulating air to pass through and increasing the temperature of the door 5 and its vicinity. However, unlike when the filter is clogged, the circulating air volume and the amount of heat generated by the self-heating heater 7c do not decrease significantly, so the temperatures of the thermistors 10a and 10b hardly decrease.

From the above phenomenon, by detecting the temperature difference between the thermistors 10a and 10c, it is possible to detect the amount of load and detect excessive load. Then, the load is appropriately dried by detecting the load amount and setting the energization time (drying time) to the self-heating heater 7c or extending the drying time according to the detected load amount. be able to. Furthermore, if an overload is detected, it is also possible to display an abnormality display to notify the user.

FIG. 5 is a flowchart showing drying control by the microcomputer 17.

In step (2), the motor 9a drives the self-heating heater 7C.

In step (2), a temperature difference α between the thermistors 10a and 10C is calculated.

In step (2), it is determined whether or not α is 0 (unit: °C, the same applies hereinafter). If α is 0, step (2) is determined to be a small load, and the drying time is set to correspond to the small load.

In step ■, it is determined whether 0≦α≦5, and 0≦
If α≦5, the load is determined to be medium in step (2), and the drying time corresponding to the medium load is set (for example, the drying time corresponding to the small load is extended by a predetermined period).

In step ■, it is determined whether or not 5α≦10, and 5
If α≦10, in step (2), it is determined that the load is a heavy load, and the drying time corresponding to the heavy load is set (for example, the drying time corresponding to the medium load is extended by a predetermined period).

In step (2), the temperature difference β between the thermistor 10c and thermistor 10b is calculated.

In step [stock], determine whether β>50 or not, and
>50 or more, in step (2), it is determined that the filter is clogged, and the display 15 displays a message indicating that the filter is clogged, and the buzzer 16 issues an alarm.

In the above step [phase], if β≦50, it is determined in step @ whether α>10 or not, and if α>10, in step A display indicating the load is displayed and a buzzer 16 is used to warn the user.

If it is determined in step @ that α≦10, then in step (2), the drying time set in steps (2) and (2) is counted.

In step (2), power supply to the self-heating heater 7a is stopped to cool the load.

In step [Yes], the drying operation is ended.

With the clothes dryer described above, it is possible to detect and display clogging of the filter, and also to detect the amount of load and set the optimum drying time according to the amount of load.

<Effects of the Invention> As described above, according to the clothes dryer of the present invention, the temperature at the door detected by the first temperature detection means and the temperature inside the circulation duct detected by the second temperature detection means are different. By detecting filter clogging based on the difference between A unique effect can be obtained.

Furthermore, the load amount can be detected based on the difference between the door temperature detected by the first temperature detection means and the circulation duct inlet temperature detected by the third temperature detection means. Since the drying time can be set according to the applied load, appropriate drying control can be performed automatically.

[Brief explanation of the drawing]

Fig. 1 is a control circuit diagram of a clothes dryer, Fig. 2 is a cross section showing an embodiment of the clothes dryer, and Fig. 3 is a control circuit diagram of a clothes dryer.
A graph showing temperature curves when the filter is normal and when the filter is clogged under rated load. Figure 4 is a graph showing temperature curves under small load and under rated load. Figure 5 is a flowchart showing the drying egg procedure using a microcomputer. . 5... Door, 6c... Lint filter, 7C...
・Self-heating heater, 10a, 10b, 10c...Thermistor, 13...
Heater drive circuit, 14...Motor drive circuit 15...
Display unit, 16...buzzer, 17...microcomputer.

Claims (1)

[Claims] 1. Rotate the fan to send air from the drying chamber through the filter into the circulation duct, heat this air with a self-heating heater placed at the outlet of the circulation duct, and send it back into the drying chamber. In a clothes dryer that circulates high-temperature air to dry clothes stored in a drying chamber, a first temperature detection means is attached to an inner wall of a door that closes the drying chamber, and a first temperature detection means is installed in the circulation duct. , a second temperature detection means is installed at a position upstream of the self-heating heater, and the difference between the temperature detected by the first temperature detection means and the temperature detected by the second temperature detection means is a predetermined value. A clothes dryer characterized by comprising filter clogging detection means that determines that the filter is clogged when the value exceeds the value. 2. Rotate the fan to send air from the drying room into the circulation duct, heat this air with a self-heating heater placed at the outlet of the circulation duct, and send it back into the drying room to circulate high-temperature air. In a clothes dryer that dries clothes stored in a drying chamber, a first temperature detection means is attached to the inner wall of a door that closes the drying chamber, and a third temperature detection means is installed near the entrance of a circulation duct that receives air from the drying chamber. temperature detection means are installed,
load amount detection means for detecting a load amount according to the difference between the temperature detected by the third temperature detection means and the temperature detected by the first temperature detection means; and drying conditions according to the load amount. A clothes dryer characterized by having a drying condition setting means for setting.