JPS6355357B2 - - 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. Ru. Reference numeral 13 denotes a drain pipe provided at the bottom of the intake duct 9 for discharging water condensed by the heat exchanger 8 (hereinafter referred to as dehumidified water) to the outside.The inner wall of the drain pipe 13 detects the presence or absence of dehumidified water. An electrode 14 is provided. 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 showing an embodiment of the present invention, and the same reference numerals as in FIG. 1 indicate the same parts. 3
0 is installed in the exhaust duct 5 and has a detection response with a time constant T ₁ Temperature detectors 1 and 31 are installed in the exhaust duct 5 near the temperature detectors 1 and 30 and are relatively larger than the time constant T ₁ A temperature sensor 2 having a detection response with a time constant T ₂ .

FIG. 5 is a block diagram showing a control device for the clothes dryer shown in FIG. 4. In the figure, 32 is a temperature difference detector that inputs temperature signals from temperature detectors 1, 30 and 2, 31 and detects the difference between the two, and 33 is a timer that measures a certain period of time from the start of drying, and its output is It is connected to a temperature difference detector 32. 34 is a temperature comparator that compares the magnitude relationship between the output ΔS of the temperature difference detector 32 and a preset set temperature _S1 , and the motor 4 and heater 10 are connected to the output end of the temperature comparator 34. There is.

Next, the operation will be explained with reference to the characteristic diagram shown in FIG. Figure 6 shows the temperature of the circulating air in the exhaust duct 5 with respect to the drying time, and the graph shown at _A1 in the figure shows the characteristics when there is a small amount of clothing to be dried, and the detection of _T1 with a small time constant. This corresponds to the output temperature signal of the temperature detector 1, 30 having a response. Characteristic A ₂ indicated by a broken line is the output temperature signal of the temperature detectors 2 and 31 at that time. Since the temperature detectors 2 and 31 are set to have a time constant T ₂ that is relatively larger than the time constant T ₁ of the temperature detectors 1 and 30, there is a delay time in response to a change in circulating air temperature. Also,
The characteristic shown in _B1 shows the temperature signal output from the temperature detectors 1 and 30 when there is a large amount of clothing, and similarly, _B2 shows the temperature signal output from the temperature detectors 2 and 31. Initially, the heat supplied from the heater 10 is used as a thermosensor to raise the temperature of the clothing and the moisture permeating it.
The clothes then dry over time, but the temperature of the circulating air does not change much because the heat is dissipated as latent heat. Eventually, when the degree of dryness approaches 100%, the heat is again consumed as a thermosensor, causing the temperature of the circulating air to rise rapidly.

The temperature difference between the temperature detectors 1 and 30 and the temperature detectors 2 and 31 (hereinafter simply referred to as temperature difference ΔS) is detected at the beginning of drying and at the end of drying when the circulating air temperature changes.

This is because the temperature detectors 2 and 31, which have large time constants, cannot follow sudden changes in temperature of the circulating air. The temperature difference ΔS is disabled during the time _t1 measured by the timer 33 from the start of drying. That is, the temperature difference detector 32 starts operating after _t1 hour. This is to prevent malfunctions. t After ₁ hour, the temperature of the circulating air becomes a constant value, and at this point the temperature detectors 1 and 3
0 and the output temperatures of the temperature detectors 2 and 31 match.
Thereafter, as the drying progresses and approaches final drying, the circulating air temperature rises again. The rate of change of this rising temperature is larger 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 temperature difference ΔS increases with time as the rate of change in the circulating air temperature increases, that is, the amount of clothing decreases. On the other hand, when finishing drying, the dryness of the clothes is 100.
[%], the circulating air temperature at the time of finishing increases as the amount of clothing increases. From this, temperature detectors 1 and 30 and temperature detectors 2 and 3
If the response time constants T ₁ and T ₂ of 1 are appropriately selected,
It is possible to indirectly detect the degree of dryness of clothing based on the temperature difference ΔS. In other words, if the temperature difference during finish drying is set to S ₁ , the rate of change in circulating air temperature is large for small quantities of clothing, so the circulating air temperature at which the temperature difference △S reaches the set temperature S ₁ is low; When the amount of clothing is large, the rate of change in the circulating air temperature is small, so the circulating air temperature at which the temperature difference ΔS reaches the set temperature S ₁ becomes high. Set temperature S ₁ is dryness 100 [%]
The temperature difference ΔS is set.

When the temperature difference ΔS input thereto matches the set temperature _S1 , the temperature comparator 34 stops power supply to the motor 4 and heater 10, and ends the operation of the dryer.

By the way, in the above explanation, the temperature detectors 1 and 30 and the temperature detectors 2 and 31 are installed in the exhaust duct 5, but they can also be installed in other circulation air channels such as the intake duct 9. If the two temperature detectors are in the same vicinity, the above operation can be expected.

Further, in the embodiment described above, the operation of the 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 when the temperature of the circulating air of a clothes dryer is near the finish drying, the temperature of the circulating air at the time of finishing and the rate of change at that time are correlated with the amount of items to be dried. , two temperature detectors with different detection response speeds are installed in the circulation air path, and the dryness of the material to be dried is indirectly detected from the detected temperature difference between the two, regardless of the amount of material to be dried. It is possible to provide a clothes dryer that can accurately detect the degree of dryness of items to be dried and can end its operation with a certain level of finished drying.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing conventional clothes drying, FIG. 2 is a block diagram showing the same control device, and FIG. 3 is a characteristic diagram showing the relationship between dryness and amount of dehumidified water with respect to drying time. FIG. 4 is a sectional view showing a clothes dryer according to the present invention, FIG. 5 is a block diagram showing the control device thereof, and FIG. 6 is a characteristic diagram showing circulating air temperature versus 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 1,
31 is a temperature detector 2, 32 is a temperature difference detector, 33
is a timer, and 34 is a temperature comparator.

Claims (1)

[Claims] 1. A drum provided rotatably within the main body,
A circulation path is formed so that air heated by a heat source is supplied into the drum, and high-temperature and humid air exhausted from the drum is heated again by the heat source after passing through a heat exchanger;
In a dehumidifying clothes dryer having a structure in which outside air crosses at right angles in the heat exchanger through the circulation path and a cooling fan, a first temperature detection device installed in the circulation path and detecting the temperature of the circulating air in the circulation path. and a temperature detection response time constant that is located in the vicinity of the first temperature detection means and installed in the circulation path, and that has a temperature detection response time constant different from a detection response time constant for the circulating air temperature of the first temperature detection means. temperature difference detection means for detecting a temperature difference between detected temperatures obtained from the rate of increase and change in circulating air temperature detected by the first and second temperature detection means; A garment comprising means for comparing the difference signal output from the detection means with a set temperature difference set corresponding to the degree of dryness during finish drying, and determining that the garment has reached the degree of finish dryness when they match. Dryer. 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 temperature difference detection means detects the first and second temperature difference from the start of drying.
2. The clothes dryer according to claim 1, wherein the clothes dryer does not operate until the temperature detected by the temperature detector reaches a substantially constant temperature.