JPH05184795A - Clothes drying machine - Google Patents

Abstract

PURPOSE:To achieve the optimum operation by judging dry condition of things to be dried accurately. CONSTITUTION:This machine has a controller so arranged that the degree of heating of air being fed into a drum 2 by a heating means 16 is reduced by a fixed value for a specified time during drying operation and drying operation is stopped when a drop in the exhaust temperature of the drum within a fixed time detected by a temperature detection means 14 does not reach a specified value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clothes dryer which dries clothes while rotating them in a rotating drum and automatically terminates the operation.

[0002]

2. Description of the Related Art Conventionally, most of the clothes dryers of this kind have been designed to control the operation time by an attached timer device, and the operation time comprehensively judged by the user from the quantity and quality of clothes. When the operation is started by setting the timer with a timer device, the operation is automatically stopped when the set time is reached. However, in such a conventional clothes dryer, since the setting of the driving time by the timer device is left to the user's sensory judgment, it is still undried at the time when the driving is finished, or conversely, it is overdried. It is easy for the clothes to be damaged, and considerable driving experience was required before the user could properly judge the driving time.

[0003]

Therefore, recently, the electric resistance value of clothes being dried is measured by electrodes, and the temperature of a clothes dryer is detected by a temperature detecting element such as a thermistor, and the measured values are detected. A clothes dryer has been proposed in which the end of drying is automatically determined from the change of the above and the operation is stopped.

However, even in the clothes dryers of these systems, for example, in the system using electrodes, the change in the electric resistance greatly varies depending on the quantity and quality of the clothes to be dried,
For example, when cotton and synthetic fiber clothes are mixed and dried, the synthetic fiber dries faster than cotton.Therefore, the time at which the end of drying is judged differs greatly depending on which resistance value the detection electrode detects. There is a risk that the accuracy of the finish will deteriorate,
Furthermore, there is a risk that the finish may differ due to changes in the ambient temperature.

On the other hand, even in the system in which the temperature detecting element detects the intake air temperature and the drum exhaust temperature, the internal temperature changes depending on the amount of clothes, and therefore complicated control is required to correct this. Further, a plurality of temperature detecting elements are required, which causes a problem of increasing cost.

The present invention has been made in view of the above, and it is possible to reliably judge the dry state of the material to be dried by a single temperature detecting means and perform the optimum operation, and it is extremely convenient to use the clothes dryer. The purpose is to provide.

[0007]

In order to solve the above-mentioned problems, the present invention firstly comprises a drum for accommodating and rotating an object to be dried, and a heating means for heating air fed into the drum. A clothes dryer having temperature detection means for detecting the temperature of the air discharged from the drum, wherein the heating degree of the air by the heating means is reduced by a certain amount during a predetermined time during a drying operation, and within a certain time. The gist of the present invention is to have control means for stopping the drying operation when the decrease in the drum exhaust temperature detected by the temperature detection means in 1 is less than a predetermined value.

Secondly, it has a drum for accommodating the material to be dried and rotating, a heating means for heating the air sent into the drum, and a temperature detecting means for detecting the temperature of the air discharged from the drum. In a clothes dryer, the time until the degree of heating of air by the heating means is decreased by a certain amount during a predetermined time during the drying operation, and the drum exhaust temperature detected by the temperature detecting means reaches a certain temperature decrease. The point is to have control means for stopping the drying operation when is longer than a predetermined value.

[0009]

In the above structure, firstly, when the input of, for example, a heater as a heating means is reduced by a certain amount at a predetermined time during the drying operation, the decrease in the drum exhaust temperature per unit time exceeds the predetermined value. If it is large, it is assumed that the heat generated by the heater is absorbed by the moisture remaining in the clothes to be dried in addition to the heat escaping from the dryer body.At this point, the clothes have not been dried sufficiently. If not, the drying operation is continued. On the other hand, the decrease in the drum exhaust temperature at this time is also affected by the capacity of the material to be dried. A garment that has been heated for a certain period of time stores the amount of heat proportional to its capacity in the garment itself. Even if the amount of heat supplied from the heater is reduced by a certain amount at this point, if the volume of the material to be dried is large, the amount of heat released from the clothes to the air inside the drum will also increase, so the decrease in the drum exhaust temperature will be small. Become. On the contrary, when the volume of the material to be dried is small, the temperature of the exhaust gas from the drum decreases greatly. A certain period of time during which the heater control is not performed is determined according to the magnitude of the decrease in the drum exhaust temperature during the continuous drying. As a result, when the decrease in the drum exhaust temperature is small, it is long, and when it is large, it is controlled so that the heater input control is not performed for a short time. It is possible to prevent the load on the circuit and the like. If the decrease in the drum exhaust temperature is smaller than a predetermined value when the drying is advanced and the heater control is restarted,
The heat from the heater escapes from the dryer body, and is hardly absorbed by the moisture of the clothes. That is, since the clothes are in a dry state, the heating by the heater is finished and the operation of the dryer is stopped. Accordingly, the dry state of the clothes can be surely known by the single temperature detecting means, and the drying operation can be ended when the clothes are in the optimum dry state.

Secondly, when the heating degree of air by the heating means is reduced by a certain amount at a predetermined time during the drying operation,
Even if the control is performed based on the time until the drum exhaust temperature reaches a certain temperature decrease, the same effect as above can be obtained.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 6 are views showing a first embodiment of the present invention.

First, the structure of the clothes dryer will be described. As shown in FIG. 1, a drum 2 is rotatably provided in a dryer main body 1. When dehydrated clothes as the material to be dried are put into the drum 2 and the operation is started, the heat exchange type fan 17 and the drum 2 are rotated by the rotation of the motor 3, and the heater 16 as the heating means is energized. It is like this. The heater 16 has a relay 21 as shown in FIGS.
The bidirectional switching element (triac) 22 allows the input power to be varied freely.
The electric power control signal of the relay 21 and the bidirectional switching element 22, the operation control signal of the motor 3, and the like are output from a microcomputer (not shown) as control means. The air heated by the heater 16 absorbs the water content of the clothes in the drum 2, becomes hot and humid, and is sucked into the surface of one of the blades of the heat exchange type fan 17. In order to measure the drum exhaust temperature at this time, a temperature detecting element 14 as a temperature detecting means is installed on the side of the component surface. Simultaneously with the intake of the heat exchange type fan 17, outside air is taken in from the intake port 11 as cooling air on the surface of the other blade so that the circulating air and the cooling air flow side by side with the blade of the heat exchange type fan interposed therebetween. It has become. Therefore, heat is exchanged between the circulating air and the cooling air via the blades, and the circulating air is deprived of heat to generate condensed water. Then, the water condensed on the drum side of the blades is blown out together with the circulating air dehumidified by the centrifugal force of the fan, and sent out into the circulation duct 5. The condensed water flows along the wall surface of the circulation duct 5, and is discharged from the machine through the drain hose 10. On the other hand, the cooled and dehumidified circulation air passes through the circulation duct 5 and is again heated by the heater 16 and fed into the drum 2. The cooling air that has taken the heat of the circulation air and becomes high temperature is exhausted from the exhaust port 12. It is discharged to the outside. Drying proceeds while repeating the above process.

Next, the control operation by the microcomputer will be described with reference to the control flowcharts of FIGS. 4 and 5 and FIG.

The electric power supplied to the heater 16 is limited to a constant time T as shown in FIG. 4 during a predetermined time during drying. If the clothes are not sufficiently dried at this time, the heat generated by the heater 16 is absorbed by the water content of the clothes in the drum 2, so that the drum exhaust temperature t greatly decreases as Δt _{1 in} FIG. 4A. To do. However, if the clothes are almost dry, the heat generated from the heater 16 is not absorbed by the moisture of the clothes, and only the amount of heat leaked from the dryer main body 1 to the surroundings is obtained. Δt _{2 in} (b)
It hardly deteriorates like.

This will be further described with reference to the control flowchart of FIG.

After the heater 16 is energized and drying is performed for a predetermined time (steps 25 and 26), the exhaust temperature t of the drum 2 is t.
After storing ₁ (step 27), the heater 16 input is limited and the exhaust temperature t ₂ of the drum 2 after a certain time T is stored (steps 28 and 29) and compared with the previously stored exhaust temperature t _1. (Step 30). When the temperature difference Δt is larger than a predetermined value, it is determined that the drying is not yet completed, the restriction on the heater input is released, and the drying is performed again (step 31). At the same time, an input restriction prohibition time of a predetermined time is set according to the magnitude of Δt (step 32). This time is the so-called load (clothes)
This is equivalent to the constant rate drying period, and thus it is possible to prevent the efficiency from deteriorating due to the input limitation that is meaningless to detect the end of drying.

Eventually, the drying progresses and the temperature difference Δ of the exhaust gas temperature
When t becomes smaller than a predetermined value, it is determined that the drying is completed, and the power supply to the heater 16 is stopped (step 3
3) Finish the operation.

FIG. 6 shows the drying time when the heater is switched from strong (1200 W) to weak (800 W) for 2 minutes every 10 minutes after the start of actual drying, and the decrease Δt in the drum exhaust temperature that occurs in 2 minutes. When the load is small to medium capacity (1
kg) and large capacity (4.5 kg). In the case of small to medium capacity, 40 to 90 minutes after the start corresponds to the constant rate drying period described above, and even if the input of the heater is limited, the temperature drop that occurs during the limitation is 2.2 ° C to 2. The temperature is kept almost constant at 6 ° C., but after 90 minutes, the amount of decrease in temperature becomes very small (at 110 minutes, it becomes about half at 1.2 ° C.). This indicates that the clothes are almost completely dry, and even if the amount of heat of the heater is limited, the clothes are not almost deprived of heat. Therefore, if the drying operation is stopped at this point, the operation can be ended in an optimum state where the clothes are dried. The same applies to the case of a large capacity, and the temperature difference hardly changes in the constant rate drying period (about 1.1 ° C) from 40 to 180 minutes after the start, but it is 0.15 ° C at 200 minutes after the start. It is a very small value. As will be described below, the control of this embodiment can detect the end of drying of clothes regardless of the load.

As described above, in the present embodiment, in the heater 16 for heating the circulating air, the dry state is detected and dried from the rate of decrease in the drum exhaust temperature within a certain time when the power supply to the heater 16 is limited. Since the end is judged, it is possible to detect the dry state of the entire clothes in the drum 2 on average, and it is possible to always carry out highly accurate drying without being affected by the material, amount, ambient temperature, etc. of the clothes to be dried. Detection can be performed.

Next, FIG. 7 shows a control mode according to the second embodiment of the present invention.

In this embodiment, when the electric power supplied to the heater 16 is reduced by a predetermined amount during a predetermined time during drying,
Contrary to the first embodiment described above, the time for the end of drying and the time for prohibiting input limitation is determined by the length of the time ΔT required until the temperature decreases by the constant temperature t. In the present embodiment as well, similar to the first embodiment, it is possible to always perform highly accurate dry detection without being affected by the material, amount, ambient temperature, etc. of the clothes to be dried.

In each of the embodiments, a dehumidifying type clothes dryer is used for explanation. However, the present invention can be applied to an exhaust type clothes dryer other than the dehumidifying type clothes dryer.

[0024]

As described above, according to the present invention,
First, the heating degree of the air sent into the drum by the heating means is reduced by a certain amount at a predetermined time during the drying operation, and if the decrease in the drum exhaust temperature within the certain time is less than the predetermined value, the drying is performed. Since the operation is stopped, it is possible to detect the dry state of the entire clothes, which is the object to be dried, on average, and reliably and easily without being affected by the difference in the material, amount, and ambient temperature of the clothes. It is possible to provide a clothes dryer that is extremely easy to use because it is possible to stop the operation by detecting the end of drying.
Moreover, since a single temperature detecting means is sufficient, the control is simple and economical.

Second, the heating degree of the air sent into the drum by the heating means is reduced by a certain amount during a predetermined time during the drying operation, and the time until the drum exhaust temperature reaches a certain temperature lower than the certain value. If the drying operation is stopped when the time becomes long, the same effect as described above can be obtained.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing a first embodiment of a clothes dryer according to the present invention.

FIG. 2 is a circuit diagram showing an example of a heater input limiting circuit in the first embodiment.

FIG. 3 is a circuit diagram showing another example of the heater input limiting circuit in the first embodiment.

FIG. 4 is a diagram showing a relationship between a drying time and a drum exhaust temperature in the first embodiment.

FIG. 5 is a control flowchart for explaining the operation of the first embodiment.

FIG. 6 is a diagram showing a time change of the temperature change rate due to a difference in the capacity of the clothes when the input of the heater is restricted at regular intervals in the first embodiment.

FIG. 7 is a diagram showing a relationship between a drying time and a drum exhaust temperature according to a second embodiment of the present invention.

[Explanation of symbols]

 2 drum 3 motor 14 temperature detection element (temperature detection means) 16 heater (heating means)

Claims (2)

[Claims] 1. A drum for storing and rotating an object to be dried,
A clothes dryer having heating means for heating the air sent into the drum and temperature detecting means for detecting the temperature of the air discharged from the drum, wherein the heating means is provided at a predetermined time during a drying operation. It is characterized by having a control means for decreasing the heating degree of air by a certain amount and stopping the drying operation when the decrease in the drum exhaust temperature detected by the temperature detecting means within a certain time does not reach a predetermined value. Clothes dryer. 2. A drum for storing and rotating an object to be dried,
A clothes dryer having heating means for heating the air sent into the drum and temperature detecting means for detecting the temperature of the air discharged from the drum, wherein the heating means is provided at a predetermined time during a drying operation. There is a control unit that reduces the heating degree of air by a certain amount and stops the drying operation when the time until the drum exhaust temperature detected by the temperature detection unit reaches a certain temperature decrease becomes longer than a predetermined value. A clothes dryer characterized in that.