JPH0693957B2 - Heater control device for dryer - Google Patents

Description

The present invention relates to a drier equipped with a heater for drying wet clothes and the like.

FIG. 1 shows the time change of the temperature difference ΔT between the exhaust temperature and the outside air temperature when the outside air is heated to dry wet clothes and the like, and it is divided into three periods as shown in the figure. . The first period shown by a is called a preheating period, the second period shown by b is called a constant rate drying period, and the third period shown by c is called a decreasing rate drying period.

During the preheating period a, heat is used to increase the temperature of the material to be dried and the temperature inside the machine. The constant rate drying period b is a period during which the water contained in the cloth evaporates steadily, and the temperature difference between the exhaust temperature and the outside air temperature is
It hardly changes. During the rate-decrease drying period c, the amount of evaporated water decreases, and the temperature difference between the exhaust temperature and the outside air temperature starts to increase.

Here, the constant rate drying period b is a period in which the water is constantly evaporated, and the water is evaporated only by supplying the latent heat of evaporation. Therefore, in this constant rate drying period b, a minimum amount of heat that keeps the temperature inside the machine may be given.

In the present invention, in the constant rate drying period, the heat generation amount of the heater is made smaller than the other periods so as to maintain the temperature inside the machine. The purpose is to dry as efficiently as if not reduced during the drying period.

Conventionally, when using a clothes dryer, the user sets the strength of the heater, that is, the heat generation amount of the heater at the start of operation, depending on the quality and weight of the material to be dried, and continues to operate until the end of drying. As a result, the user consumes extra power.

The present invention solves the above conventional problems. FIG. 2 shows the basic configuration of the present invention. In the figure, 1 is an outside air temperature detecting section, and 2 is an exhaust temperature detecting section from an object to be dried in a dryer. The signals obtained by the outside air temperature detection unit 1 and the exhaust temperature detection unit 2 are input to the temperature difference detection unit 3. And
The output signal of the temperature difference detection unit 3 and the output signal of the reference voltage setting unit 4 are compared by the comparison unit 5, and the control unit 6 is operated by the obtained signal to control the heat generation amount of the heater 7.

The control unit 6 controls the heat generation amount of the heater to be small when the temperature difference between the outside air temperature and the exhaust temperature is within a predetermined range.

An embodiment of the present invention will be described below with reference to FIGS. FIG. 3 shows an electric circuit diagram, and FIG. 4 shows a reference voltage set value.

The voltages obtained by the outside air temperature detection unit 1 and the exhaust gas temperature detection unit 2 are input to the temperature difference detection unit 3, and this temperature difference detection unit 3
Output voltage is passed through a filter composed of a resistor 8 and a capacitor 9, and the output voltage and the reference voltage of the reference voltage setting unit 4 are compared by the comparison means 5, and the control means constituted by the relay 6 by the obtained signal. Is operated to control the heat generation amount of the heater 7 to be small.

The outside air temperature detection unit 1 is composed of a resistor 10 and an outside air temperature detecting thermistor 11, and a voltage corresponding to the outside air temperature is obtained. The exhaust gas temperature detector 2 is composed of a resistor 12 and an exhaust gas temperature detecting thermistor 13, and a voltage with respect to the exhaust gas temperature is obtained.

The temperature difference detecting unit 3 is composed of resistors 14, 15, 16, 17 and an operational amplifier 18, and functions as a differential amplifier. Further, the reference voltage setting unit 4 is composed of resistors 19, 20, 21, 22 and
The reference voltage levels V ₂ and V ₁ shown in FIG. 4 are set by the resistor 20, the resistor 21, and the resistor 22 respectively.

The comparing means 5 is composed of comparators 23, 24 and resistors 25, 26, 27, and keeps the output at a zero level only during the input voltage is between V ₁ and V ₂ and opens the contact 6 ′ of the relay 6 which is the controlling means to open the heater. Decrease the calorific value of 7. In FIG. 3, 28 is a drum that contains the material to be dried, a motor that rotationally drives a blower fan that moves the air heated by the heater 7, 29
Is an AC power supply.

INDUSTRIAL APPLICABILITY As described above, the present invention makes use of the fact that moisture is steadily evaporated if heat is supplied to keep the temperature inside the machine during the constant rate drying period. The amount of heat generated is reduced and the drying time is about the same as when the amount of heat generated by the heater is not reduced, and the effect is that power can be used efficiently.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between drying time and ΔT (difference between outside air temperature and exhaust temperature), FIG. 2 is an electrical block diagram of a heater control device of the present invention, and FIG. 3 is an embodiment of the present invention. FIG. 4 is an electric circuit diagram showing a reference voltage setting value. 1 ... Outside air temperature detection unit, 2 ... Exhaust temperature detection unit, 3 ...
Temperature difference detection section, 4 ... Reference voltage setting section, 5 ... Comparison means, 6 ... Control means, 7 ... Heater.

Claims (2)

[Claims] 1. A means for detecting a temperature difference between an outside air temperature and an exhaust temperature from an object to be dried, a reference voltage setting section, and an electric signal obtained by the means for detecting a temperature difference between the outside air temperature and the exhaust temperature. A heater controller for a dryer, comprising: a unit that compares the electric signals obtained by the reference voltage setting unit; and a unit that controls the heat generation amount of the heater by the electric signal obtained by the comparing unit. 2. A heater heater control for a dryer according to claim 1, wherein the means for controlling the heat generation amount of the heater controls the heat generation amount of the heater when the temperature difference between the outside air temperature and the exhaust temperature is within a predetermined range. apparatus.