JPH0454477B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION The present invention is used for drying clothes, etc., and particularly relates to a control device for controlling the degree of drying of a general household clothes dryer.

Configuration of conventional examples and their problems A common method for detecting the drying speed in conventional household clothes dryers is the so-called electrode type, which detects changes in the electrical resistance value at both ends of the electrodes that come into contact with the clothes to be dried. Although detection means are known,
When using such a detection means, there is a large variation in the resistance value change depending on the material and mass of the clothing, etc., and when configured to automatically stop operation when the set resistance value is reached, drying at the end of operation This has the drawback of causing inconveniences such as energy loss due to overdrying and insufficient drying.

OBJECT OF THE INVENTION The present invention is intended to solve the above-mentioned conventional drawbacks, and to change the degree of drying according to the material and mass of the clothes to be dried so as to always obtain accurate and appropriate drying results, and to change the degree of drying. The purpose is to realize switching with a simple configuration.

Structure of the Invention In order to achieve the above object, the control device for a clothes dryer of the present invention includes an exhaust temperature detection device that converts exhaust temperature into voltage and outputs it, and an A- D conversion circuit and this A-
The exhaust temperature is detected by the time signal of the D conversion circuit,
A microcomputer that stops energizing the heater when the time of the A-D conversion circuit increases from the time corresponding to the temperature at which the exhaust temperature is maintained at a constant value, and a drying rate setting that is input to this microcomputer. The drying rate switching circuit changes the relationship ratio between the voltage and time of the A-D conversion circuit according to a signal.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below based on the drawings.

Figure 1 is a graph showing the correlation between the operating time t and the exhaust temperature T in the operating state of a clothes dryer.When the operation is started and the heater is energized and the blower is driven, the exhaust temperature rises and then remains constant. maintained at the value. When the moisture in the clothes to be dried evaporates and the drying rate reaches nearly 100%, the exhaust temperature begins to rise rapidly. The time when the exhaust temperature starts to rise rapidly like this
The heater continues to be energized from t ₁ until the time t ₂ when the exhaust temperature rises by the set temperature difference △T ₁ minute, and the rise time t ₂
After reaching this point, the heater energization is stopped and the operation is switched to only blowing air, thereby rapidly reducing the exhaust gas temperature as shown by the broken line A in FIG. This is taken as the standard drying rate. Similarly to the above, the heater continues to be energized from the time t ₁ until the time t ₃ when the exhaust temperature rises by a set temperature difference △T ₂ minutes larger than the above, and the rising time t ₃
After reaching this point, the heater energization is stopped and the operation is switched to only blowing air, thereby rapidly reducing the exhaust gas temperature as shown by the solid line B in FIG. This is set as a drying rate higher than the standard drying rate. As mentioned above, the drying rate is to be controlled by controlling the limit of increase in exhaust temperature in two stages, and FIG. 2 is a block diagram of a control device for this purpose.

In FIG. 2, 1 is an exhaust temperature detection device, 2 is an A-D conversion circuit that converts the detected exhaust gas temperature signal (analog signal) by the detection device 1 into a digital signal according to the rise in exhaust temperature, and 3 is a user An input device for setting the degree of drying; 4 is the A-D conversion circuit 2;
and a microcomputer that operates according to the input signal of the input device 3; 5 and 7; a heater drive circuit and a blower motor drive circuit that are equipped with a power switching device and the like that operate according to the output signal of the microcomputer 4; 6 and 7; 8 is a heater and a motor; 9 is an input signal value from the A-D converter circuit 2 to the computer 4 in response to a signal from the microcomputer 4, that is, the voltage of the exhaust temperature detection device and the time of the A-D converter circuit; This is a drying rate switching circuit that changes the relative ratio of .

The A-D conversion circuit 2 converts voltage changes in accordance with the rise in exhaust gas temperature into time and digital signals that can be measured by the microcomputer 4, and is composed of a lamp generator 20, a discharge circuit 21, and a comparator 22. has been done.

FIG. 3 is a specific circuit diagram of the A-D converter circuit 2, and its operation and function will be explained with reference to _FIG . When the discharging circuit 21 is operated through the resistor _R6 via the resistor R6 to turn the transistor _TR1 from on to off, the charging transistor _TR2 is turned on, and the capacitor C is charged with a constant current, and the terminal voltage of the capacitor C is Vc.
increases linearly with time, as shown by virtual line C in FIG. Resistors R ₁ , R ₂ , R ₃ , and R ₄ are all bias circuits. Then, at the time _t1 , the set voltage Vs formed by the thermistor and the resistor _R5 , which is an example of the exhaust temperature detection device 1, is compared with the terminal voltage Vc of the capacitor C, and the comparator 22
The microcomputer 4 measures and stores the time tc ₁ until it is reversed.

Next, the terminal voltage Vc of capacitor C is set voltage Vs
When the voltage reaches , the transistor _TR1 turns on and the terminal voltage Vc of the capacitor C becomes zero. Similarly, the _time tc 2 from when the transistor TR ₁ changes from on to off to when the comparator 22 reverses is measured, and when the time difference between the two △tc = tc ₂ - _{tc 1} reaches the set value, the exhaust temperature changes to △ It is determined that _T1 has increased. That is, when the exhaust temperature rises and the resistance value of thermistor 1 decreases, the set voltage Vs increases, and the comparator 2
The time required for the second inversion also becomes longer.

Next, when the degree of drying is set to be high through the resistor _R7 by the input device 3, the transistor _TR3 is turned on, the base current of the charging transistor _TR2 increases, and the charging time of the capacitor C becomes faster.

As the charging time becomes faster in this way, if the set time difference △tc is constant, the voltage change will be large, and the resistance change of the thermistor 1 will also be large, as shown by the solid line D in Fig. 4.
As shown in , the temperature rise change becomes larger.

In the above example, the charging time constant of the lamp generator 20 is changed to control the rise in exhaust temperature and the degree of drying, but as an alternative method, the time difference △tc is changed in at least two stages. The drying degree may be controlled by allowing settings to be changed.

Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

(1) It detects the rise in exhaust temperature and controls the exhaust temperature by load control according to the detected temperature, so it can accurately control the drying rate without being affected by the material or weight of the clothes to be dried. can be done.

(2) Since the user can change the degree of drying in at least two stages as necessary, the usability is greatly improved.

(3) Since the degree of drying can be controlled in at least two stages, there is great flexibility in designing the dryer, especially the load control device, which is advantageous in terms of design and manufacturing.

(4) When the degree of drying is switched, the drying rate switching circuit changes the relationship ratio between the voltage and time of the A-D conversion circuit and outputs it to the microcomputer.
The microcomputer itself can easily handle this without creating a special program for changing the drying rate, improving its versatility.

[Brief explanation of the drawing]

FIG. 1 is a graph showing the control means of the clothes dryer of the present invention, FIG. 2 is a block diagram, FIG. 3 is a specific control circuit diagram, and FIG. 4 is a control explanatory diagram of the one shown in FIG. 1 is an exhaust temperature detection device, 2 is an A-D conversion circuit,
3 is an input device, 4 is a microcomputer, 5 is a heater drive circuit, 6 is a motor drive circuit, 7 is a heater, 8 is a motor, and 9 is a drying rate switching circuit.

Claims (1)

[Claims] 1 An exhaust temperature detection device that converts exhaust temperature into voltage and outputs it, an A-D conversion circuit that converts the voltage of this exhaust temperature detection device into time, and a time signal of this A-D conversion circuit that detects the exhaust temperature. However, if the time of the A-D conversion circuit increases from the time corresponding to the temperature at which the exhaust temperature is maintained at a constant value, a microcomputer that stops energizing the heater and a drying input input to this microcomputer A control device for a clothes dryer, comprising a drying rate switching circuit that changes the relationship ratio between the voltage and time of the A-D conversion circuit based on a rate setting signal.