JPH07112097A - Clothes drier - Google Patents

Abstract

PURPOSE:To control a current within a prescribed current value while controlling the ON/OFF of a semiconductor heater at the early time of operation, thereafter detecting the current for the purpose of constant-current control in order to shorten a drying time. CONSTITUTION:When a semiconductor heater 13 is divided into elements 13a, 13b, and the operation is started by a start switch, the element 13a, 13b are subjected to ON-OFF control. Thereafter, while detecting a current by a current sensor 22, a rotation of a motor 18 is controlled by a controller 25, that is, a rotation of a double-sided fan is controlled, the air quantity of dehumidifying air flowing into the semiconductor heater 13 is controlled, and finally, the current is controlled within a prescribed value. Accordingly, the operation can be executed by a prescribed current irrespective of fluctuation factors such as the air quantity, an atmospheric temperature, etc., and an inexpensive and practical clothes drier for aiming the shortening of time is obtained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clothes dryer, and more particularly to a clothes dryer capable of shortening the drying time as compared with the conventional case when current control is performed using a semiconductor heater of a positive temperature coefficient thermistor. Regarding the improvement of the machine.

[0002]

2. Description of the Related Art In a semiconductor heater using a positive temperature coefficient thermistor, (1) the amount of heat generated, that is, the current fluctuates depending on the amount of air passing through the semiconductor heater (FIG. 6).

(2) The amount of heat generated, that is, the electric current fluctuates depending on the temperature of the air flowing through the semiconductor heater (FIG. 7).

(3) It has a feature that the current changes when the voltage changes, that is, the current increases when the voltage decreases.

Since a semiconductor heater using a positive temperature coefficient thermistor has a small resistance at room temperature, it generates heat when a voltage is applied and, until the resistance increases, a stable current called a rush current is generated. Double the excessive current flows (Fig. 4).

For this reason, in the clothes dryer using the semiconductor heater, as a countermeasure, in regard to (1),
Find the usage conditions that produce the maximum air volume, and make settings so that the allowable current of the household outlet is not exceeded under these conditions.

Regarding (2), the operating environment temperature is assumed, and the setting is made so that the allowable current of the household outlet is not exceeded within this environment temperature.

With respect to (3), a means such as setting a current is adopted by assuming the lowest operating voltage.

With respect to (4), in order to prevent the operation of the breaker or the current fuse, the semiconductor heaters are divided and the semiconductor heaters are sequentially turned on to disperse and suppress the inrush current ( (Fig. 4).

However, in (1), when the load is low, the air flow rate increases, when the load is high, the pressure loss increases, and the air flow rate decreases, so the heat generation amount decreases.

For this reason, the amount of heat originally required to be increased and the amount of heat generated is desired to be increased.

Similarly, in (2), when the outside air temperature rises, the calorific value decreases, which is a factor of extending the drying time.

As a countermeasure for the following (1) and (2) including the above (4), there is a method of increasing the number of divisions of the semiconductor heater to sequentially turn on the semiconductor heater when the heat generation amount is reduced. It is conceivable, but (a) the control is inevitably discontinuous, and the reduction cannot be completely covered.

(B) If the number of divisions is increased as much as possible in order to reduce discontinuities, wiring complexity and control complexity are incurred.
It becomes a factor of high cost.

Therefore, recently, by detecting the current of the semiconductor heater, if the maximum set current is exceeded, the air volume is reduced to reduce the heat generation amount, and if the minimum set current is cut off, the air volume is increased and the heat generation amount is increased. Such air volume control, specifically, the rotation control of the blower, that is, the rotation control of the motor has come to be considered.

However, in the case of the rotation control, in order to deal with the characteristics of the semiconductor heater described above, that is, the problem of the inrush current, the problem of the air volume, the temperature of the air, and the voltage of the Rotational control is required within the range of 40 to 50% of the rotational speed.

In this case, it is required to output the same output at a rotation speed of 40 to 50% of the conventional motor having a single rotation speed, and (a) the motor must be extremely large. (B) The range of rotation control is large, and the number of factors that cause noise increases, which causes new problems such as the need for mitigation measures.

[0018]

In order to shorten the drying time, it is a great condition to always be able to operate in any state at the maximum constant current within the allowable current of household outlets. A simple and inexpensive controller is required to implement.

[0019]

In order to achieve the above object, in the present invention, (1) ON / OFF control of divided semiconductor heaters is performed at the initial stage of operation with large current fluctuation.

Since the ON-OFF control period may be about 5 minutes in the initial stage, the control may be discontinuous, but the influence on the whole may be small.

(2) From the time when the stable current is entered,
For the fluctuation of the current value due to the fluctuation of the air temperature and voltage, the flow rate of the dehumidified air entering the semiconductor heater is controlled while detecting the fluctuation of the current value by the current sensor, and the constant current is controlled by the air volume control by controlling the rotation speed of the motor. Take control.

If the divided semiconductor elements are sequentially turned on at the beginning of operation, the inrush current at the beginning of operation can be suppressed.

Since the inrush current is almost twice the stable current,
If the rotation control in this portion can be avoided, the maximum rotation number of the rotation control is 70 to 80%, and it is possible to suppress an extreme increase in the output of the motor.

[0024]

When all the semiconductor heaters are energized at the beginning of operation with large current fluctuations, the current does not immediately drop to a stable current. Especially in the dehumidifying no-duct type dryer called the circulation type, the air temperature flowing into the semiconductor heater is generally higher than that of the exhaust type dryer, and it takes a long time to reach a stable current.
During this time, the breaker and current fuse have the potential to operate easily.

Therefore, a part of the semiconductor heater divided during this period is ON-OFF controlled to reduce the thermal energy applied to the breaker or the current fuse, and the section of about 5 minutes is overcome.

Next, when approaching the stable current region, the total current of the semiconductor heater, which changes depending on the amount of air flowing into the semiconductor heater, the temperature of the air flowing into the semiconductor heater, the voltage, etc., is detected. For example, if the rotation speed of the motor that drives the blower is reduced to control the air volume and the current is small,
The rotation time of the motor is increased to control the air volume so that the motor can always be operated with a predetermined constant current under any condition to shorten the drying time.

By the way, when the semiconductor heater is energized, the resistance of the semiconductor heater at room temperature is small, and at the same time when the semiconductor heater is energized, an inrush current of about twice the normal use stable current flows, so the semiconductor heater is divided (assumed to be divided into two). It is preferable that the divided semiconductor heaters are sequentially energized without being turned on at a time, and the delay time of this energization may be about 10 seconds. Thus, when the divided semiconductor elements are sequentially turned on in the initial operation. In addition to the above effects, it is possible to further suppress the inrush current at the initial stage of operation.

[0028]

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

First, a series of dryer configurations will be described with reference to FIGS.

A back cover 2 is fixed to the rear surface of the outer frame 1.

A clothes inlet 3 and a door 4 for opening and closing the inlet 3 are also installed on the front surface of the outer frame 1, and the metal annular drum support 5 fixed to the outer frame 1 and the inside of the outer frame 1 are provided. A drum 7 serving as a drying chamber is rotatably supported by a rear bearing 6 arranged in the rear portion.

On the rear surface of the drum 7, there is formed a hot air outlet 8 having a large number of holes.

At the hot air inlet 9 formed in the lower part of the drum support plate 5, a circulation path 10 is formed which is communicated with the ventilation port 12 of the fan casing 11.

A semiconductor heater 13 facing the hot air inlet 9 and comprising elements 13a and 13b using a positive temperature coefficient thermistor.
And an L-shaped duct 14 fixed to the drum support plate 5
The semiconductor heater 13 is housed inside.

A heat exchange type double-sided fan 16 is located in the fan casing 11 and is rotatably supported by the rear bearing 6 via a metal.

A motor 18 is arranged above the outer frame 1 to rotate the drum 7 by means of an idler pulley 23 and a belt 24 and rotate the double-sided fan 16 by means of a pulley belt 17.

A filter 19 is attached from the inside of the drum 7 so as to cover the hot air outlet 8 of the drum 7.

A temperature sensor 20 and a humidity sensor 21, each of which is a thermistor, are mounted in the circulating air passage at a position facing the hot air outlet 8 of the fan casing 11 in order to detect a change in the state of the dry air.

A control device 25 for carrying out a series of drying operations and incorporating a current sensor 22 is arranged on the side surface of the outer frame 1.

An operating portion 26 is arranged on the front surface of the outer frame 1.

A power switch 27, a drying course selection switch 28, a heater switching setting switch 29 for setting the amount of heat generated by the heater, and a drum 7 are intermittently operated to prevent wrinkles from being generated on the cloth after the drying operation. Input device 32 including soft guard setting switch 30, start switch 31 for starting operation, and display device 3
3 and 3 are provided.

The operation of this embodiment will be described below.

When driving, the door 4 is first opened, the dehydrated clothes are stored in the drum 7, and the power switch 2 is turned on.
Enter 7.

In this state, the dry course is set to the automatic operation course, the heater is set to be strong, and the fluffy guard is set to operate intermittently.

When the start switch 31 is pressed, an automatic driving course in which the temperature sensor 20 and the humidity sensor 21 detect the state of dry air is executed.

First, the motor 18 and the semiconductor heater 13 are energized to rotate the drum 7, and the double-sided fan 16 rotates at high speed.

The air in the circulation path 10 is heated by the semiconductor heater 13 and sucked into the drum 7 through the hot air inlet 9 as high temperature dry air.

The high-temperature dry air sent into the drum 7 comes into contact with the clothes in the drum 7, promotes the evaporation of the water contained in the clothes, and becomes high-temperature and high-humidity air, and the filter 19 collects the waste cloth. Then, it is sucked by the double-sided fan 16 in the fan casing 11.

Double-sided fan 1 from the cooling air inlet 2a of the back cover 2
When it is cooled to a temperature below the dew point temperature by the outside air sucked into 6, and condensed water is generated on the circulation path side of the double-sided fan 16,
The condensed water is discharged out of the machine through the drain port 15 of the circulation path 10.

The circulating air, which has lost a part of its water content when passing through the double-sided fan 16, becomes dehumidified air, which is heated by the semiconductor heater 13 provided in the L-shaped duct 14 and then reheated as high-temperature dry air to the drum 7 again. It is sent inside and used for drying clothes.

As the moisture in the clothes dryer evaporates, the humidity of the dry air decreases and the temperature rises.

The semiconductor heater 13 so that the temperature does not become excessive.
Based on the input from the temperature sensor 20 while turning on and off the element 13a or the element 13b of FIG.
Control and wait for the input of the humidity sensor 21.

When the dry air reaches a predetermined humidity, the semiconductor heater 13 is turned off by the input of the humidity sensor 21, only the motor 18 is operated, and the cold air operation for cooling the drying room and the clothes is performed for about 10 minutes. Stop.

It should be noted that when the start switch 31 is pressed down, the motor 18 is energized, the drum 7 and the double-sided fan 16 are rotated, and at the same time, the semiconductor heater 13 is energized and heated.

When the elements 13a and 13b of the semiconductor heater 13 are energized at the same time, an inrush current of about 30 A flows as shown by the broken line in FIG. 4, but depending on the magnitude of this inrush current, it may be in the home. The breaker and the current fuse of this may operate.

Therefore, the element 13a of the semiconductor heater 13
When either one of 13b is first energized and the remaining elements are energized after about 10 seconds, the inrush current is divided into about two as shown by the solid lines in FIGS. 4 and 5, so that the maximum value of the inrush current is greatly suppressed.

Next, all the elements 13a of the semiconductor heater 13 are
Even when the current is supplied to 13b, it does not reach the stable current immediately. Especially, in the circulation type clothes dryer, the temperature of the air entering the semiconductor heater 13 is high and it takes time to reach the stable current.

If this state continues, the breaker or fuse may operate due to this, but in order to reduce the total energy applied, one of the elements 13a and 13b of the semiconductor heater 13 is turned on and off. So-called ON-OFF control is performed to prevent the breaker and fuse from operating. The period during which this ON-OFF control is performed is about 5 minutes after the start.

Next, 5 minutes after this ON-OFF control,
As shown in FIG. 5, while detecting the total current with the current sensor 22, the controller 25 controls the rotation of the motor 18, that is, controls the rotation of the double-sided fan 16 and controls the air volume of the dehumidified air flowing into the semiconductor heater 13. While controlling the current within a certain range.

That is, if the current value exceeds a certain range, the rotation speed of the double-sided fan 16 is decreased, and if the current value is decreased, the rotation speed of the double-sided fan 16 is increased.
The current is controlled to a specified value within a certain range.

Factors that cause the current to change are: (1) Fluctuation of the air volume itself: the amount of load introduced into the drum 7, and also the degree of clogging of the filter 19 with thread waste (2) Wind Temperature: Varies depending on the temperature environment in which the clothes dryer is installed (3) Voltage: If the voltage is low, the amount of heat generated will increase, so the current will increase; conversely, if the voltage is high, the amount of heat generated will be decreased However, the current is controlled to a constant value against these fluctuations.

Further, there are inverter control and phase control as the rotational speed control method of the motor 18, but the phase control is generally advantageous in terms of price against the fluctuation.

[0063]

As in the present invention, (1) split ON-OFF control of the elements of the semiconductor heater 13 is performed at the beginning of operation with large current fluctuations. (2) Current due to fluctuations in air volume, air temperature, and voltage after the initial operation. By controlling the air volume of the dehumidified air entering the semiconductor heater 13 while detecting the fluctuation of the value with the current sensor 22 and controlling the current to a constant value, the range of the rotation speed control of the motor 18 is reduced and the power of the motor 18 is reduced. It is possible to reduce the factor of up, and it is possible to use an inexpensive motor. It is possible to suppress power up of the motor 18 to be small, and it is easy to take mitigation measures against noise generated by the phase control method. Since the OFF control is about 5 minutes in the initial stage, the power loss due to the ON-OFF control is extremely small from the whole, and it is a factor that lengthens the drying time Number of small ON-OFF control is small and the semiconductor heater 1
3 or the effect on the life of the control system is small.
It is possible to provide an inexpensive clothes dryer that takes advantage of the characteristics of the rotation speed control of 8 and aims at a practical and time saving.

In addition to the above-mentioned structure, as shown in the previous embodiment, if the semiconductor elements composed of a plurality of elements are sequentially turned on at the initial stage of operation, in addition to the above effects, Inrush current at the beginning of operation can be suppressed.

[Brief description of drawings]

FIG. 1 is a partially cutaway side view showing the internal structure of a clothes dryer according to an embodiment of the present invention.

FIG. 2 is an external perspective view of the clothes dryer shown in FIG.

3 is a block diagram of a control device indicated by reference numeral 25 in FIG. 2, an operation unit 26, and related parts.

FIG. 4 is a current characteristic diagram by current control of a conventional clothes dryer.

FIG. 5 is a current characteristic diagram by current control of the clothes dryer according to the present invention.

FIG. 6 is an air flow-current characteristic diagram of a semiconductor heater.

FIG. 7 is an air temperature-current characteristic diagram of a semiconductor heater.

[Explanation of symbols]

13 ... Semiconductor heater, 16 ... Double-sided fan, 18 ... Motor, 20 ... Temperature sensor, 21 ... Humidity sensor, 22 ...
Current sensor, 25 ... Control device.

Claims (2)

[Claims] 1. A drum rotatably supported in an outer frame, a semiconductor heater composed of a plurality of elements using a positive temperature coefficient thermistor for sending warm air into the drum, an air blower, and an air blower, A clothes dryer equipped with a motor for driving a drum, equipped with a speed control device for a blower device controlled by the input of a current sensor for detecting the current of a semiconductor heater, and a semiconductor device including a plurality of devices at the initial stage of operation. Some elements of O
N-OFF control is performed to suppress the total current including the motor and the semiconductor heater, and when the current is stable after the initial stage of operation, the air flow rate of the blower is adjusted by the speed control device to control the current of the semiconductor heater constant. Characteristic clothes dryer. 2. The semiconductor device according to claim 1, wherein in the initial stage of operation, the semiconductor devices made up of a plurality of devices are sequentially turned on to suppress an inrush current, and then the semiconductor devices made up of the plurality of devices are turned on.
A clothes dryer characterized by N-OFF control.