JPH07213796A - Drier - Google Patents

Abstract

PURPOSE:To prevent the shrinkage and drying irregularities of an object to be dried in a short drying operation period by setting the temperature in a drum low, and setting the reading time interval of the dry state detection signal long when the normal operation course is selectively switched to the low- temperature operation course. CONSTITUTION:A drum 2 in an outer box 1 is supported by a fan casing 6 via a shaft 5, and it is rotatively driven by a drum motor 20 via a belt 21. A hot-air feeding device 19 is formed with a heater 17 and a blast fan device 18 constituted of a fan 9, a fan motor 11, and a duct 16. An electrode 22 detecting the dry state of an object to be dried is arranged on a drum support member 4. When the normal operation course is selectively switched to the low-temperature operation course in this drier, the temperature in the drum 2 is set relatively lower after the dry state reaches the set level, and the reading time interval of the detection signal outputted from the electrode 22 is set relatively longer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is configured to automatically control a drying operation of a material to be dried based on a detection signal from the electrode while detecting a dry state of the material to be dried. Regarding dryers.

[0002]

2. Description of the Related Art In this type of dryer, after it is detected that the drying rate of an object to be dried reaches 100% based on a detection signal from an electrode, the drying operation is continued for a certain period of time before drying. I am trying to finish the operation. in this case,
During the drying operation, the heater of the warm air supply means is continuously energized to keep the temperature inside the drum at a high temperature.

[0003]

However, in the above-mentioned conventional structure, there is a problem that the clothes shrink considerably depending on the material of clothes to be dried, for example.
The reason why the clothes shrink in this way is that the temperature inside the drum, that is, the temperature of the clothes is set high and the drying operation is executed. However, if the temperature is set low, there is a problem that the time required for the drying operation to end, that is, the drying operation time, becomes extremely long.

[0004] Here, the present inventor has studied a drying operation method which can suppress shrinkage of clothes as much as possible and which does not lengthen the drying operation time so much. Then, the present inventor performs various experiments to perform the drying operation at a high temperature until the drying rate of the clothes reaches a predetermined drying rate of about 90% (so-called iron detection time), and thereafter. It was discovered that when the temperature inside the drum is set to a low temperature and the drying operation is performed until the end, the shrinkage of the clothes is reduced as much as possible and the drying operation time is not so long. However, when various experiments were performed to control the drying operation in this way, there was a drawback that uneven drying of clothes occurred.

Therefore, it is an object of the present invention to reduce the shrinkage of the material to be dried as much as possible without prolonging the drying operation time, and to prevent the occurrence of unevenness in the drying of the material to be dried. To provide a dryer.

[0006]

A dryer of the present invention detects a dry state of a material to be dried, a drum for containing the material to be dried, a hot air supply means for supplying hot air into the drum. In a dryer comprising an electrode and an operation control means for automatically controlling a drying operation of the material to be dried based on a detection signal from the electrode, a selection for switching and selecting a normal operation course and a low temperature operation course A switch, the operation control means, when the low-temperature operation course is selected, after the dry state of the material to be dried reaches a set level, after the temperature in the drum during execution of the normal operation course The temperature is set lower than the temperature, and the reading time interval when reading the detection signal output from the electrode is controlled to be set longer than the reading time interval when executing the normal operation course. It is intended to.

Further, in the above structure, when the warm air supply means has a heater, it is preferable to set the temperature in the drum to a low temperature by controlling the heater to switch on and off. Further, when the warm air supply means has a plurality of heaters, it is possible to set the temperature in the drum to a low temperature by cutting off a part of the plurality of heaters. Furthermore, when the warm air supply means is composed of a PTC heater and a blower fan device, the temperature inside the drum is lowered by controlling the rotation speed of the blower fan of the blower fan device to decrease. It is also a preferable mode to set to.

[0008]

When the temperature inside the drum is set to a low temperature after the iron is detected, the present inventor seeks the cause of uneven drying of the material to be dried. As a result, they have found that there is a problem in the reading time interval when the operation control unit reads the detection signal output from the electrode. Specifically, after the iron detection time, the operation control means changes the reading time interval when reading the detection signal output from the electrode, in proportion to the magnitude of the detection signal, in length. , The temperature inside the drum is lower than the normal drying operation (normal drying course), but the detection signal is read at the same reading time interval as in the normal drying operation, so the completion of drying is detected (drying rate is 100%. The detection of the fact that the temperature has reached is reached sooner, and unevenness in drying occurs. Therefore, if the reading time interval is set to be longer than the normal drying course, the determination of the completion of drying can be made accurate, and unevenness in drying of the dried object can be prevented.
The present invention is based on this point.

That is, according to the above means, after the dry state of the material to be dried reaches the set level (for example, iron detection), the temperature inside the drum is set lower than the temperature at the time of executing the normal operation course, and Since the reading time interval when reading the detection signal output from the electrode is set to be longer than the reading time interval when executing the normal operation course, the drying operation time does not become so long and the dried object does not shrink. It is reduced as much as possible, and unevenness in drying of the material to be dried does not occur.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, in FIG. 2 showing a schematic overall configuration of a dryer, a drum 2 is rotatably housed inside an outer box 1. Specifically, a large-diameter opening 3 formed in the front surface of the drum 2 is rotatably supported by a drum support 4 provided in the front portion of the outer box 1, and the rear portion of the drum 2 is A shaft 5 provided at the center of the surface portion is rotatably supported by a fan casing 6 provided at a rear portion of the outer case 1.

At the central portion of the front surface of the outer box 1, a material inlet / outlet 7 is formed, and a door 8 for opening / closing the material inlet / outlet 7 is pivotally installed. In addition, a heat exchanger, for example, a double-bladed fan 9 is rotatably provided in the fan casing 6 via a shaft 10.
The fan 9 is arranged so as to partition the inside of the fan casing 6 into front and rear. Further, the fan 9 is configured to be rotationally driven via a belt 12 by a fan motor 11 disposed in the rear portion of the bottom of the outer box 1. In this case, when the fan 9 is rotationally driven, the air in the drum 2 is sucked to the front side in the fan casing 6 through the filter 13 in the inner part of the drum 2 by the air blowing action, and the air outside the machine is removed. It is sucked into the rear side of the fan casing 6 through the outside air intake port 15 of the outer case back plate 14. As a result, the air inside the drum 2 and the air outside the machine are heat-exchanged via the fan 9, so that the air inside the drum 2 is dehumidified.

The dehumidified air is supplied from the front side into the drum 2 through a duct 16 (only a part of which is shown in FIG. 2) extending in the front-rear direction and is returned. Here, a heater 17 is arranged at the front end of the duct 16, and the heater 17 heats the air supplied into the drum 2. As shown in FIG. 3, the heater 17 is composed of, for example, two PTC heaters 17a and 17b. In this case, the fan 9, the fan casing 6, the motor 11, the duct 16 and the like constitute the blower fan device 18. The blower fan device 18 and the heater 17 constitute warm air supply means 19.

On the other hand, the drum 2 is rotatably driven via a belt 21 by a drum motor 20 disposed on the front side of the bottom of the outer box 1. Further, in the upper part of the drum support 4 facing the inside of the drum 2,
An electrode 22 for detecting the drying rate (dry state) of the material to be dried and the amount of the material to be dried is provided. The electrode 22 is composed of a pair of electrodes made of, for example, stainless steel arranged on the insulating substrate.

Further, in FIG. 3 showing the electrical configuration by functional blocks, the operation control means, for example, the microcomputer 23 stores a control program for controlling the overall drying operation of the dryer. DC power is supplied to the microcomputer 23 from a commercial AC power supply 24 via a rectifier circuit 25. The commercial AC power supply 24 is supplied to the fan motor 11, the drum motor 20, and the two PTC heaters 17a and 17b via a power switch 26, respectively. And these motor 11, motor 20, PTC
The heaters 17a and 17b are configured to be controlled to be turned on and off by the microcomputer 23 via the drive circuit 27.

Here, the fan motor 11 is composed of, for example, a DC brushless motor, and the microcomputer 23 has a structure in which the rotation speed of the motor 11 (fan 9) can be appropriately adjusted via a drive circuit 27. ing. Further, the microcomputer 23 receives the detection signal output from the electrode 22 via the detection circuit 28, and also receives a switch signal from the start temporary stop switch 29, for example, a course change switch 30 which is a selection switch.
From the temperature sensor 31 for detecting the temperature inside the drum 2, and the clock pulse from the clock pulse generation circuit 32. As shown in FIG. 2, the temperature sensor 31 is disposed on the front side of the fan casing 6 and configured to detect the temperature of the air discharged from the drum 2, that is, the exhaust temperature.

The detection circuit 28 is composed of a peak hold circuit, a contact frequency measuring circuit, and the like. The peak hold circuit receives a detection signal from the electrode 22 and generates a signal corresponding to the drying rate of the material to be dried, and supplies the signal to the microcomputer 23. Further, the contact frequency measuring circuit receives a detection signal from the electrode 22 and generates a signal corresponding to the amount of the material to be dried, and supplies the signal to the microcomputer 23.

Next, the operation of the above structure will be described with reference to FIGS. FIG. 4 is a flowchart showing the general control contents of the control program stored in the microcomputer 23 mainly for the control of the low temperature operation course. First, the material to be dried is accommodated in the drum 2, the power switch 26 is turned on, and the course switching switch 30 is operated to set a driving course, in this case, a normal driving course (normal drying course) (step S1). ). Then, when the start temporary stop switch 29 is turned on, the process proceeds to “YES” in step S2, and the microcomputer 23
Thus, the heater 17, the motor 11, and the motor 20 are energized and driven (step S3). As a result, the drum 2 is rotationally driven, and the warm air is supplied into the drum 2 by the heating of the heater 17 and the blowing action of the fan 9, and the drying of the material to be dried in the drum 2 proceeds. Go.

When the material to be dried comes into contact with the electrode 22, the electrode 22 outputs a detection signal Sa as shown in FIG. 1 (a). The detection signal Sa is a voltage signal of about + EV when the object to be dried is wet (state where the drying rate is low), and is a voltage signal whose voltage value decreases as the drying rate of the object to be dried increases. . The detection signal Sa from the electrode 22 passes through the peak hold circuit of the detection circuit 28 to become a drying rate detection signal Sb as shown in FIG. 1C, and this drying rate detection signal Sb is the microcomputer 23. Given to. In this case, the microcomputer 23 is configured to read the drying rate detection signal Sb at the reading time interval t1 (that is, equal intervals) until the drying rate of the material to be dried reaches the drying rate of iron detection (for example, 95%). Has been done. The iron detection drying rate is not limited to the above-mentioned value of 95%, but is 80-
It is preferable to set an appropriate value from the range of about 95%.

Now, as the drying of the material to be dried progresses, as shown in FIG.
As shown in (b), when the drying rate of the material to be dried reaches the drying rate detected by the iron at time ta, the process proceeds to “YES” in step S4 to determine whether the set drying operation course is the low temperature operation course. It is determined whether or not (step S5).
In this case, since it is a normal operation course, the process proceeds to “NO} in step S5, and the same drying operation as before is continued until the drying rate of the dried object reaches the drying detection drying rate (for example, 100%) ( Go to "NO" in step S6).

After that, when the drying rate of the material to be dried reaches the drying detection drying rate, the process proceeds to "YES" in step S6,
After performing the same drying operation as before until a predetermined time (step S7), the heater 17 is turned off and the fan 9 is turned off.
The air-blowing operation (cooling operation) for rotationally driving is performed for a predetermined time (step S8), and then the drying operation is ended. In the above-mentioned normal operation course, as shown by the curve P1 in FIG. 1 (f), it can be seen that the temperature inside the drum 2 (exhaust gas temperature) gradually rises after iron detection. Therefore, in the above-mentioned normal operation course, as shown in FIG.
As shown by the curve Q1, it can be seen that the shrinkage rate of the clothes to be dried has increased to about 8 to 9%.

Next, the case where the low temperature operation course is set as the drying operation course will be described. In this case, after the low temperature operation course is set (step S1) and the drying operation is started (step S2), until the drying rate of the material to be dried reaches the drying rate detected by the iron, that is, at time ta.
Drying operation is carried out in the same manner as the above-mentioned normal operation course until the temperature reaches.

Now, when the drying rate of the material to be dried reaches the drying rate of iron detection (that is, the dry state of the material to be dried is a set level), the determination of step S5 is performed. In this case, since it is the low temperature operation course, the process proceeds to "YES" in step S5. Then, the time interval when the microcomputer 23 reads the dryness detection signal Sb, that is, the read time interval t is set to k times the read time interval t when executing the normal operation course (step S9). However, k is a constant larger than 1. Here, even when the normal operation course is executed, after the ironing is detected, the reading time interval t of the microcomputer 23 is controlled to be varied in proportion to the height (voltage value) of the drying rate detection signal Sb. However, in the low temperature operation course, such variable control is performed, and if the voltage value of the drying rate detection signal Sb is the same, the reading time interval t is set to be k times the length of the normal operation course. We are in control.

At the same time, the heat output of the heater 17 is lowered to lower the temperature inside the drum 2. In the present embodiment, the temperature inside the drum 2 is controlled so as to be maintained at an average temperature of 25 to 50 ° C. Specifically, the heater 17 has two PTC heaters 17a and 17b.
Therefore, the blowing ability of the fan 9 is reduced. That is, in this case, since the iron has just been detected (the drying rate of the material to be dried has not reached the drying rate of the drying detection), the process proceeds to “NO” in step S10, and the drum 2
It is determined whether the internal temperature T is lower than the upper limit temperature TH. At this time, since the iron has just been detected,
As shown by the curve P2 in (f), the temperature T in the drum 2
Is higher than the upper limit temperature TH, the process proceeds to "NO" in step S11. Then, the rotation speed of the fan motor 11 is reduced and the rotation speed of the fan 9 is set to VL (step S12). As a result, the temperature T in the drum 2
Is decreasing.

Thereafter, as shown in FIG. 1 (f), time t
In b, when the temperature T in the drum 2 has dropped to the lower limit temperature TL, the process proceeds to "YES" in step S11 and to "NO" in step S13. Then, the rotation speed of the fan motor 11 is slightly increased to
As shown in (g), the rotation speed of the fan 9 is set to VH (step S14). As a result, the temperature T in the drum 2 rises. After that, at time tc, when the temperature T in the drum 2 rises to the upper limit temperature TH, the process proceeds to “NO” in step S11, the rotation speed of the fan motor 11 is reduced, and the result is shown in FIG. Thus, the rotation speed of the fan 9 is set to VL (step S12). Hereinafter, the rotation speed of the fan 9 is raised and lowered between VH and VL to control the temperature T in the drum 2 between the upper limit temperature TH and the lower limit temperature TL.

Then, in the state where the temperature control inside the drum 2 is continued as described above, the microcomputer 23 reads the drying rate detection signal Sb from the electrode 22 and the detection circuit 28 as shown in FIG. 1 (d). The reading is performed at an interval t (a variable time interval that increases or decreases in proportion to the voltage value of the drying rate detection signal Sb). Then, the drying of the material to be dried progresses, and
As shown in (d), when the drying rate of the material to be dried reaches the drying rate of drying detection (100%) at time td, the process proceeds to “YES” in step S10. Then, after performing the same drying operation as before for a predetermined time (step S7), a blowing operation (cooling operation) for turning off the heater 17 and rotating the fan 9 is performed for a predetermined time. After that (step S8), the drying operation is finished at time te.

In the low temperature operation course, as shown by the curve P2 in FIG. 1 (f), the temperature inside the drum 2 (exhaust temperature)
It can be seen that is kept at a low temperature. Therefore, in the above low temperature operation course, as shown by the curve Q2 in FIG. 1 (e), the shrinkage rate of the clothes to be dried was suppressed to about 4% (see the point of time te). I understand. Moreover,
In this case, since the reading time interval t of the microcomputer 23 after the iron detection is set to be longer than the normal drying course, the determination of the dry detection becomes accurate, and the occurrence of the drying unevenness of the material to be dried can be surely prevented. You can

Here, as a comparative example, the reading time interval t of the microcomputer 23 after iron detection is set to the same timing as the normal drying course (read time interval t), and only the temperature T in the drum 2 after iron detection is set. The drying operation course in which is set to a low temperature (maintained between the upper limit temperature TH and the lower limit temperature TL) will be described. Also in the case of the driving course of this comparative example, until the drying rate of the material to be dried reaches the drying rate of iron detection, that is, until the time ta is reached,
Drying operation is performed in the same manner as the above-described normal operation course and low temperature operation course. Then, after the ironing is detected, the reading time interval t of the microcomputer 23 is the same timing as the normal drying course, so that the microcomputer 23 detects from the electrode 22 and the detection circuit 28 as shown in FIG. The drying rate detection signal Sb of is read.

In this case, although the temperature inside the drum 2 is lower than that in the normal drying operation (normal drying course), the detection signal is read at the same reading time interval t as in the normal operation course, so that the drying is completed. The detection (detection that the drying rate has reached 100%) is early, specifically, at time tf. Therefore, after this, if the drying operation is continued for a certain period of time and the blowing operation is continued for a certain period of time and the drying operation is finished at the time tg, unevenness in drying occurs on the material to be dried. As is clear from the graphs of FIGS. 1C and 1D, in the low temperature operation course of the present embodiment, the reading time interval t when the microcomputer 23 reads the drying rate detection signal Sb is normally set. Since it is set to k times the reading time interval t when executing the driving course, the time t2 ′ from the iron detection to the dry detection in the present embodiment.
However, the time t2 from the iron detection to the dry detection in the comparative example is almost k times. The time t3 from the detection of drying to the end of the drying operation is a constant time.

According to this embodiment having such a configuration, the low temperature operation course can be set to be switched, and when the low temperature operation course is set, the temperature inside the drum 2 is lower than the temperature during the normal operation course after iron detection. With setting, electrode 22
Also, since the reading time interval t for reading the drying rate detection signal Sb output from the detection circuit 28 is set to be longer than the reading time interval for executing the normal operation course, the drying operation time is not so long. The material to be dried can be dried, and the shrinkage of the material to be dried can be reduced as much as possible (the shrinkage ratio is almost the same as that in the case of sun-drying). Furthermore, it is possible to reliably prevent the occurrence of drying unevenness of the material to be dried. In addition, in order to realize the low temperature operation course, it is sufficient to improve the control program (software) of the microcomputer 23, so that the manufacturing cost hardly increases.

In the above embodiment, the fan motor 1 is used.
Although 1 is composed of a DC brushless motor, it is not limited to this, and may be composed of, for example, an induction motor, and the rotational speed of the induction motor can be adjusted (varied). The method of adjusting the rotation speed of the induction motor is to control the ratio of interruption and interruption of the induction motor by phase control or cycle control, or to adjust the AC frequency of the induction motor to a high or low level. There is a method of doing so, and either method is acceptable. Also, fan 9
As a method of lowering the heat output of the heater 17 without changing the blowing capacity of the heaters, for example, a method of turning off the heaters or a method of turning off some of the heaters when the number of heaters is plural is available. Yes, any method is preferable.

[0031]

As is apparent from the above description, the present invention is provided with a selection switch for switching between the normal operation course and the low temperature operation course, and the operation control means is provided when the low temperature operation course is selected. After the dry state of the material to be dried reaches the set level, the temperature inside the drum is set lower than the temperature during the normal operation course, and the reading time interval for reading the detection signal output from the electrode is set. Since it is configured to control so as to be set longer than the reading time interval during execution of the normal operation course, it is possible to minimize shrinkage of the material to be dried without increasing the drying operation time so much, and It has an excellent effect that it is possible to prevent the occurrence of drying unevenness of the dried product.

Further, in the case of the above construction, when the temperature inside the drum is set to a low temperature, if the warm air supply means has a heater, the heater is switched on and off to control the heat generation amount of the heater. The temperature in the drum can be reduced and the temperature in the drum can be easily set to a low temperature. Furthermore, when the warm air supply means has a plurality of heaters, a part of the plurality of heaters is cut off to reduce the heat generation amount of the heaters and easily set the temperature inside the drum to a low temperature. be able to. Furthermore, when the warm air supply means is composed of a PTC heater and a blower fan device, the amount of heat generated by the PTC heater is reduced by controlling the rotation speed of the blower fan of the blower fan device to decrease. The temperature inside the drum can be easily set to a low temperature.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention, in which (a)-
(G) is a detection signal from an electrode, a drying rate, a drying rate detection signal of Examples and Comparative Examples, a shrinkage rate of clothes, a temperature in a drum,
Graph showing changes in fan rotation speed

[Figure 2] Vertical side view of the entire dryer

FIG. 3 is a block diagram.

[Fig. 4] Flow chart

[Explanation of symbols]

1 is an outer box, 2 is a drum, 6 is a fan casing, 7 is an inlet / outlet of an object to be dried, 8 is a door, 9 is a fan, 11 is a motor, 1
3 is a filter, 17 is a heater, 17a and 17b are PTC
A heater, 18 is a blower fan device, 19 is a warm air supply means,
20 is a motor, 22 is an electrode, 23 is a microcomputer (operation control means), 28 is a detection circuit, 30 is a course changeover switch (selection switch), 31 is a temperature sensor, 32
Indicates a clock pulse generation circuit.

Claims (4)

[Claims] 1. A drum for containing a material to be dried, a hot air supply means for supplying warm air into the drum, an electrode for detecting a dry state of the material to be dried, and a detection signal from the electrode. A dryer comprising an operation control means for automatically controlling the drying operation of the material to be dried, comprising a selection switch for selectively selecting a normal operation course and a low temperature operation course, wherein the operation control means comprises: When the low-temperature operation course is selected, the temperature inside the drum is set lower than the temperature during execution of the normal operation course after the dry state of the material to be dried reaches the set level, and from the electrode. A dryer, which is controlled so that a reading time interval at the time of reading an output detection signal is set to be longer than a reading time interval at the time of executing the normal operation course. 2. The dryer according to claim 1, wherein, when the warm air supply means has a heater, the temperature inside the drum is set to a low temperature by controlling the heater to be turned on and off. 3. The temperature inside the drum is set to a low temperature by cutting off a part of the plurality of heaters when the warm air supply means has a plurality of heaters. Dryer. 4. When the warm air supply means is composed of a PTC heater and a blower fan device, the temperature in the drum is controlled by controlling the rotation speed of the blower fan of the blower fan device to decrease. The dryer according to claim 1, wherein the dryer is set to a low temperature.