JPS6355358B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention forms a hot air circulation path using a rotating drum, a circulation fan, a heating source, and a heat exchanger,
This invention relates to a so-called dehumidifying type clothes dryer that condenses and recovers moisture from clothes stored in a rotating drum by cooling a heat exchanger, and in particular detects the degree of dryness of items to be dried in the clothes dryer. This relates to improvements in equipment.

[Prior art]

FIG. 1 is a sectional view showing a conventional clothes dryer disclosed in, for example, Japanese Unexamined Patent Publication No. 55-70300. Motor 4 via drum belt 3 on drum
Driven by. Reference numeral 5 designates an exhaust duct provided at the rear of the drum 2, in which a circulation fan 6 is installed, and this circulation fan 6 is rotationally driven by a motor 4 via fan belts 1 and 7. A heat exchanger 8 is connected at one end to the exhaust duct 5 and at the other end to the intake duct 9. A heater 10 is installed in the intake duct 9 and heats the air in the circulation path formed by the drum 2, the exhaust duct 5, the heat exchanger 8, and the intake duct 9. A cooling fan 11 is provided near the heat exchanger 8 and blows outside air toward the heat exchanger 8 to cool the heat exchanger 8. The cooling fan 11 is rotationally driven by the motor 4 via fan belts 2 and 12. . Reference numeral 13 is provided at the bottom of the intake duct 9 to collect water condensed by the heat exchanger 8 (hereinafter referred to as dehumidified water).
An electrode 14 is provided on the inner wall of the drain pipe 13 to detect the presence or absence of dehumidified water. Reference numeral 15 denotes a door that covers the clothes slot on the front side of the outer box 1.

In the clothes dryer shown in FIG. 1, when items to be dried are placed in a drum 2 and a drying operation is started, the drum 2 is rotated around a horizontal axis by the power of a motor 4 via a drum belt 3. Circulation fan 6 and cooling fan 11 driven by motor 4 at the same time
is operated, the circulation fan 6 sucks the air inside the drum 2, and circulates the air through the exhaust duct 5, the heat exchanger 8, and the intake duct 9 so that it is blown into the drum 2 again. (Hereinafter, this air will be referred to as circulating air)
At this time, the circulating air heated by the heater 10 in the intake duct 9 evaporates moisture from the material to be dried that has been put into the drum 2. Therefore, drum 2
The air flowing out becomes hot and humid. On the other hand, the cooling fan 11 takes in outside air and blows it to cool the heat exchanger 8. When the high-temperature and humid air passes through the heat exchanger 8, it is dehumidified by heat exchange with outside air, and the dehumidified water is discharged to the outside from the drain pipe 13.

FIG. 2 is a block diagram showing a control device for the clothes dryer shown in FIG. 1, in which the same reference numerals as in FIG. 1 indicate the same parts. A determination circuit 20 inputs the detection signal from the electrode 14 and determines the presence or absence of dehumidified water. A timer 21 is connected to the output of the determination circuit 20. When the determination circuit 20 determines that the dehumidified water has run out, the timer 21 stops power supply to the motor 4 and heater 9 after counting a certain period of time t.

Next, the operation of the clothes dryer having the above structure will be explained with reference to a drying characteristic diagram shown in FIG. FIG. 3 shows the degree of dryness of clothes and the amount of dehumidified water with respect to the drying time. In the figure, "A" indicates the degree of dryness of the clothes, and "B" indicates the change in the amount of dehumidified water per unit time. After the dryer starts operating, dehumidified water will begin to be discharged outside a few minutes later. When the degree of dryness exceeds a certain value, the amount of dehumidified water becomes constant, and as the drying progresses and the degree of dryness approaches, the amount gradually decreases and finally reaches zero.

However, at this point, the clothes are not yet dry.

When the dehumidified water passes through the drain pipe 13, the electrode 14 sends a signal to the determination circuit 20. Since the dehumidified water flows out intermittently through the drain pipe 13, the signal becomes a pulse. When the determination circuit 20 determines that the detection pulse from the electrode 14 is no longer present, the timer 21 is activated.
Activate. When the timer 21 measures a preset time t, the motor 4 and the heater 1
0 power supply is stopped and the drying operation is ended.

As described above, in the conventional apparatus, the drying operation is stopped after a predetermined period of time has elapsed after determining the presence or absence of dehumidifying water and detecting that the dehumidifying water has run out. However, the time from when the dehumidifying water runs out until the finished dryness is reached varies depending on the amount of clothing. For this reason, there are drawbacks such as over-drying or insufficient drying depending on the amount of clothes.

[Purpose of the invention]

The present invention was made in order to eliminate the above-mentioned conventional drawbacks, and an object of the present invention is to provide a clothes dryer that can accurately detect the degree of dryness of objects to be dried without being affected by the amount of objects to be dried. With the goal.

[Embodiments of the invention]

FIG. 4 is a sectional view of a clothes dryer according to an embodiment of the present invention, and FIG. 5 is a block diagram showing a clothes dryer control device according to an embodiment of the present invention. A temperature detector 30 is installed in the exhaust duct 5 and detects the temperature of the circulating air.The output of the temperature detector 30 is connected to an integrating circuit 31 and a comparator 32. 33 is a timer that measures a certain period of time from the start of drying, the output of which is connected to the integrating circuit 31. Comparator 32
inputs the detection signal of the temperature detector 30 and the integral signal of the integrating circuit 31, and compares the magnitude relationship between the two. Furthermore, the motor 4 and the heater 10 are connected to the output end of the comparator 322.

Next, the operation will be explained with reference to the characteristic diagram shown in FIG. Figure ₆ shows the temperature detection signal of the temperature detector 30 and the integral signal of the integrating circuit 31 with respect to the drying time. This corresponds to the temperature characteristics of the circulating air inside the duct 5. Characteristics indicated by dashed lines
A ₂ shows the integral signal at that time. Further, B ₁ indicates a temperature detection signal when there is a large amount of clothing, and similarly, B ₂ indicates an integral signal.

Initially, the heat supplied from the heater 10 is used as sensible heat to raise the temperature of the clothing and the moisture that permeates into it, and then the clothing dries over time, but the heat is consumed as latent heat, so the temperature of the circulating air remains low. It does not change. Eventually, the degree of dryness will reach 100 [%]
As the temperature approaches, the heat is again consumed as sensible heat, causing the temperature of the circulating air to rise rapidly. During the time T measured by the timer 33 from the start of drying, the integrating circuit 3
1 is not activated, the temperature detection signal and the integral signal show the same value after T time has elapsed.
Thereafter, even if the drying progresses, the temperature of the circulating air does not change, so the two values show the same value. Then, as the drying approaches the end, the temperature of the circulating air increases and a difference is detected between the temperature detection signal and the integral signal. The rate of change in the temperature of the circulating air increases for the characteristic _A1 , which has a small amount of clothing, than for the characteristic _B1 , which has a large amount of clothing, and is approximately inversely proportional to the amount of clothing. Further, the speed at which the integral signal follows the circulating air temperature is influenced by the rate of change of the temperature detection signal. That is, the smaller the amount of clothing, the greater the difference between the temperature detection signal and the integral signal. On the other hand, if finish drying is defined as the point when the degree of dryness of the clothes reaches 100%, the finished circulating air temperature increases as the amount of clothes increases. From this, if the integration time constant of the integration circuit 31 is appropriately selected, it is possible to indirectly detect the degree of dryness of the clothing based on the signal difference between the temperature detection signal and the integration signal. In other words, if the signal difference at the time of finishing drying is set to Δt, the circulating air temperature will be such that the difference between the detected temperature signal and the integral signal reaches the set signal difference Δt, since the rate of change in circulating air temperature is large for small quantities of clothing. is low, and conversely, when the amount of clothing is large, the circulating air temperature that reaches the set signal difference Δt becomes high. When the difference between the temperature detection signal from the temperature detector 30 and the integral signal from the integration circuit 31 matches the set signal difference Δt, the comparator 32 controls the motor 4 and the heater 1.
0 power supply is stopped and the operation of the clothes dryer is ended.

By the way, in the above description, a case has been described in which the temperature detector 30 is installed in the exhaust duct 5, but the above-described operation can be expected if it is installed in another circulation air path such as the intake duct 9, for example.

Further, in the embodiment described above, the operation of the clothes dryer is terminated immediately after finish drying is detected, but the power supply to the heater 10 may be stopped and cold air operation may be performed.

〔Effect of the invention〕

As explained above, this invention utilizes the fact that the temperature of the circulating air during finishing and the rate of change at that time is correlated with the amount of material to be dried. A temperature detector is used to detect the temperature, an integration circuit that integrates the detection signal from the temperature sensor with a predetermined time constant, and a comparator that compares the detection signal of the temperature detector and the integral signal from the integration circuit. Since the dryness of the material to be dried is detected by
It is possible to provide a clothes dryer that can accurately detect the degree of dryness of objects to be dried regardless of the amount of objects to be dried, and can end its operation with a certain level of finished drying.

[Brief explanation of drawings]

Figure 1 is a sectional view showing a conventional clothes dryer.
Fig. 2 is a block diagram showing the control device, Fig. 3 is a characteristic diagram showing the relationship between dryness and dehumidifying water amount with respect to drying time, and Fig. 4 is a cross section showing a clothes dryer according to an embodiment of the present invention. 5 is a block diagram showing an embodiment of a control device for a clothes dryer according to the present invention,
FIG. 6 is a characteristic diagram showing a circulating air temperature detection signal and an integral signal with respect to drying time. In the figure, 1 is an outer box, 2 is a drum, 5 is an exhaust duct, 6 is a circulation fan, 8 is a heat exchanger, 9 is an intake duct, 10 is a cooling fan, 30 is a temperature detector, 3
1 is an integrating circuit, 32 is a comparator, and 33 is a timer.

Claims (1)

[Claims] 1. A drum provided rotatably within the main body,
A circulating air path is formed so that high-temperature and humid air is supplied into the drum heated by a heat source and exhausted from the drum through a heat exchanger and heated again by the heat source, and the outside air is exchanged with the heat by the circulating air path and the cooling fan. In a dehumidifying type clothes dryer having a structure that is orthogonal to each other in the dryer, a temperature detector installed in the circulating air path detects the temperature of the circulating air, and a detection signal from the temperature detector is transmitted at a predetermined time constant. an integrating circuit that integrates,
The difference signal between the detection signal corresponding to the finishing drying temperature increase rate detected by the temperature detector and the integral signal from the integrating circuit is compared with a setting signal set corresponding to the degree of dryness during finishing drying, and it is found that they match. and a means for determining when the clothes have reached the final dryness level. 2. The clothes dryer according to claim 1, wherein the clothes dryer stops operating when it is determined that the clothes have reached a finished dryness level. 3. The clothes dryer according to claim 1, wherein the clothes dryer operates with cold air for a desired time after determining that the clothes have reached the final dryness level. 4. The clothes dryer according to claim 1, wherein the integrating circuit does not operate from the start of drying until the temperature detected by the temperature detector continues to reach a substantially constant temperature.