JPS5914892A - Drying detecting apparatus of dryer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drying detection device that automatically detects the end of drying in a dryer.

Currently, when using a dryer, a user sets a timer depending on the weight of the material to be dried.

However, the required drying time is easily affected by room temperature, humidity, etc.

Sometimes two pages become over-dry, and setting the timer time is troublesome for some users.

In addition, conventionally, there are dryness detection devices such as electrode type, but these devices are complicated and have many parts.In particular, the mounting location of the detection part is limited by the rotating drum, and the wiring part is complicated and expensive. As shown in FIG. 1, the present invention utilizes the relationship between the drying rate and the current flowing through a self-temperature-controlled heater (hereinafter simply referred to as a heater) having a positive resistance-temperature characteristic. .

That is, at the start of operation, a rush current flows through the heater.

After a while, the current value remains at a certain constant value, and as the object to be dried begins to dry, the current value becomes smaller than the constant value. When the heater current reaches A1, the object to be dried is completely dried. Therefore, it can be seen that it is necessary to detect the current flowing through the heater and automatically control the dryer to stop when the current value is A. Also, if the door is opened during drying, the current will drop as shown by the dashed line a, and if suboptimal operation is performed, the current value will change to the dotted line b3 as shown by 1'', and the current value When it reaches A1, the dryer can be stopped.

The present invention provides a dryness detection device for a dryer that can detect the end of drying of the object by detecting the current value A1 flowing through the heater and automatically control the dryer to stop. However, according to the present invention, the detection part is not affected by the mounting location on the drum, which is a rotating body, so that the wiring part is simple and the number of parts is reduced, and the dryness detection device can be made at low cost. can be provided.

Next, the structure and operation of the present invention will be explained with reference to the block diagram shown in FIG. 2.

Reference numeral 1 designates an AC power supply, 2 a motor for rotating the drum and a blower fan for supplying drying air under pressure, and 3 a heater. 4
is the start button, and by this operation, motor 2. The heater 3 starts to be energized. The current flowing through the heater 3 is converted into voltage by the current detection means 5. S [When the ambient temperature detection section receives the output from this, a temperature-corrected reference voltage is generated in the reference voltage setting section 7.

Here, the voltage converted by the current detection means 5 and the reference voltage determined by the reference voltage setting section are compared by the comparison means 8. If the voltage converted by the current detecting means 6 becomes lower than the reference voltage set by the reference voltage setting section T, the control means 9 operates, and the motor 2. The power supply to the heater 3 is stopped. Reference numeral 1o denotes a control operation delay section that delays the operation of the control means 9 until the inrush current of the heater 3 flows at the start of operation.

An embodiment embodying the present invention will be described below with reference to FIG. In the figure, 1 is an AC power supply, 2 is a motor, and 3 is a heater. When the start switch 4 is pressed by operating the start button 4, a rush current flows through the heater 3, and a DC voltage is obtained by the current detection means 5. Reference numeral 6a denotes a thermistor constituting the ambient temperature detection section 6, through which a temperature-corrected reference voltage is set by the reference voltage setting section 7. The voltage obtained by the current detection means 5 and the reference voltage provided by the reference voltage setting section 7 are compared by a comparator 8 which is a comparison means 8. If the voltage 5V obtained by the current detection means 5 is lower than the reference voltage set by the reference voltage setting section 7, the relay 9 is activated and the motor 2. The power supply to the heater 3 is stopped. The control operation delay section 1o delays the operation of the relay 9 until a rush current flows through the heater 3 at the start of operation.

The start switch 4 is connected to the relay 11. Relay contact 11a
In addition, when the current value flowing through the heater 3 is larger than a set value, a circuit 12 is configured to maintain that state.

The current detection means 6 detects the current flowing through the heater 3 with a current transformer 13, and outputs the output from a diode 14. Capacitor 5. The voltage is smoothed by a resistor 16 and a DC voltage corresponding to the current flowing through the heater 3 is output.

The reference voltage setting section 7 is composed of an ambient temperature detection thermistor 6 and a resistor 1. 1, control action delay section 1o
is capacitor 18. Transistor 19. It is composed of a resistor 20 and delays the operation of the relay 9 until an inrush current flows into the heater 3. Note that 21 is a door switch.

As described above, according to the present invention, the current of the self-temperature-controlled six-page heater is detected and the drying is completed, and for example, unlike the conventional electrode method, it is not affected by the rotating drum. Accurate dryness detection can be performed with a simple configuration, and the wiring structure can be simplified and the number of parts can be reduced.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the relationship between the current value flowing through the self-temperature control type heater and the drying rate, Fig. 2 is an electrical block diagram showing the basic configuration of the present invention, and Fig. 3 is an electrical diagram of an embodiment of the present invention. It is a circuit diagram. 3... Self-temperature control type heater, 6-...
Current detection means, 6... Ambient temperature detection section, 7...
...Reference voltage setting section, 8...Comparison means, 9
...control means.

Claims (1)

[Claims] Current detection means for detecting a current flowing through a self-temperature-controlled heater that is a heat source for drying air; and ambient temperature detection means;
The current detecting means comprises a reference voltage setting section, and a comparing means for operating a control device that compares the voltage obtained by the current detecting means with the voltage obtained by the reference voltage setting section and determines energization to the load. A dryness detection device for a dryer that operates a control device that determines energization to the load based on the output voltage level of the dryer, and stops the dryer.