JPH0148037B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a control device for a clothes dryer having a dryness detection function.

Conventional Structures and Problems With the spread of clothes dryers in recent years, various dryness detection methods have been proposed in order to save energy and improve usability. However, they still have many problems and cannot be said to be optimal dryness detection means.

In other words, with the method of detecting the resistance value of clothing by installing a pair of electrodes inside the drum, it is extremely difficult to provide moisture-proof insulation for the control circuit due to the high impedance measurement, and it is also difficult to provide moisture-proof insulation for the control circuit, and it is difficult to provide moisture-proof insulation for the control circuit. Since it must be used directly, there are major safety issues. In addition, this method has a drying rate of 90
It is only possible to determine the condition up to ~95%, and it is necessary to set a delay time in some way until complete drying is achieved, which generally results in poor accuracy.

There is also a method that uses changes in the exhaust temperature of the drum, but this method is easily affected by the ambient temperature, and the pattern of temperature change is uneven depending on the quantity and quality of the clothes being dried. Due to these changes, the drying rate at the end of the process will vary and accuracy will deteriorate.

There is also a dryness detection method that can detect several levels of dryness in order to achieve the degree of dryness desired by the user, but basically the above-mentioned methods are used alone or in combination to detect dryness. Accuracy is generally poor, and the large dispersion is particularly problematic when detecting the standard degree of dryness that is most often used.

Purpose of the Invention The present invention overcomes the above-mentioned problems and provides a clothes dryer that optimally detects several levels of dryness, particularly detects standard dryness with high accuracy, and has a highly reliable dryness detection function. It is intended to be realized.

Structure of the Invention The present invention includes a condensed water detection device and a temperature detection device installed in the exhaust path of a drum, a first degree of dryness corresponding to a dryness rate suitable for ironing, and a second degree of dryness corresponding to a standard finish. and a third drying degree corresponding to careful drying, and a setting section that can set a third drying degree corresponding to careful drying, and a setting unit that allows the time rate of change in the drum exhaust temperature to reach a predetermined value or more after a constant rate drying period using the temperature detecting device. The time when the condensed water detection device disappears is detected as a first degree of dryness, and the time when the condensed water in the exhaust path of the drum disappears is detected as a second degree of dryness, and the time when the first degree of dryness is reached. and a control unit that detects, as a third degree of dryness, the time when an appropriate delay time corresponding to the time from the time when the second degree of dryness is reached.

The user selects the desired degree of dryness from among these three levels of dryness and inputs it into the control unit, and the control unit detects that the degree of dryness specified by the user has been reached through the detection process described above. After that, the power supply to the heater is stopped, and after a certain period of cold air operation, the power supply to the motor is also stopped to end the operation.

DESCRIPTION OF THE EMBODIMENTS FIG. 1 shows a block diagram of an embodiment of the present invention.
1 is a drum for storing clothes to be dried; 2 is a drum 1
3 is a heater that heats the air flowing into the drum 1
4 is a motor for driving the drum 1 and the fan 3, and the drum 1 and the fan 3 are connected to a belt or the like. connected by a power transmission means. 5 is a condensed water detection device, and 6 is a temperature detection device, each of which is installed at an appropriate position in the exhaust path of the drum 1, and detects the presence or absence of condensed water and its temperature. The condensed water detection device 5 detects the presence or absence of condensed water on the exhaust path wall using a condensation sensor that has a characteristic that the resistance value is large when there is condensed water and small when there is no condensed water. Temperature detection device 6
detects the exhaust temperature of the drum 1 using a temperature dependent resistor with a negative temperature coefficient. Reference numeral 7 denotes a control unit, and 8 a setting unit. The degree of dryness desired by the user is input to the setting unit 8, and the control unit 7 receives the outputs of the condensed water detection device 5 and the temperature detection device 6, and determines this degree of dryness. Heater 2 and motor 4 to achieve
Controls energization to.

In the figure, thin black arrows indicate electrical connections, thick black arrows indicate mechanical connections, and white arrows indicate air flow.

FIG. 2a shows a change in temperature detected by the temperature detection device 6, and FIG. 2b shows a change in the presence or absence of condensed water detected by the condensed water detection device 5. As shown in FIG. 2a, the exhaust temperature of the drum 1 is constant during the constant rate drying period, but begins to rise near the end of the drying period when the decreasing rate drying period begins. This is when the first degree of dryness (drying rate of 90 to 95%, hereinafter referred to as iron drying) is reached, which is considered to be suitable for ironing. The control unit 7 determines that the constant rate drying period is reached when the exhaust temperature of the drum 1 detected by the temperature detection device 6 becomes stable, and furthermore, the slope dT/dt of this temperature is 3.
The time when the temperature becomes higher than ℃/min is determined to be the time when iron drying is reached.

Further, as shown in FIG. 2b, condensed water on the wall of the exhaust path of the drum 1 starts to adhere when the amount of water vapor generated from the clothes to be dried in the drum 1 exceeds a certain amount some time after the start of operation. At the end of drying, almost no steam is generated and the condensed water disappears. This point is when the second degree of dryness (drying rate of 100 to 102%, hereinafter referred to as standard dryness) is reached, which is considered to be a standard drying state, and is detected by the control unit 7.

In addition, the time from iron drying to standard drying (△t in Figure 2 b) is measured by the control unit 7, and the third drying degree (drying rate of 102 to 104%, hereinafter referred to as careful drying) is measured by the control unit 7. ) is used to determine the arrival time. That is, in this embodiment, as shown in the figure, a delay time is provided from the standard drying time by the same time as the time Δt from the iron drying time to the standard drying time, and the time after this delay time is defined as the time when careful drying is reached. In this embodiment, this delay time and △t are made to match, but depending on the setting degree of careful drying, the delay time may be changed to k·△t (k is a positive constant, for example
1.2) may also be used. In this case, the larger k is set, the higher the drying rate during careful drying can be.

FIG. 3 is a flowchart showing this dryness detection process.

The degree of dryness to be achieved is entered in advance by the user into the setting section 8, and when the control section 7 detects that the degree of dryness has been reached through the above-described detection process, it first stops energizing the heater 2. After shifting to the cold air operation and lowering the temperature of the clothes to be dried by the cold air operation for 5 minutes, the energization to the motor 4 is also stopped and the operation is ended.

Effects of the Invention In the clothes dryer of the present invention, the dryness detection method using the condensed water detection device can accurately detect the standard dry state without being affected by the ambient temperature or the quantity or quality of the clothes to be dried. Therefore, compared to the standard method of detecting dryness based only on the drum exhaust temperature, almost all of its drawbacks can be covered. Further, this standard drying is considered to be the drying level most desired by users, and this method is considered to be a very effective method because it can detect this state with high accuracy.

In addition, as in the present invention, by adding the use of changes in the exhaust temperature of the drum detected by the temperature detection device, it is possible to detect iron drying and even careful drying, which is extremely practical in practice. Improves usability.

Furthermore, the present invention does not have the safety problems of the conventional electrode type, and the electronic circuit section of the control section can also have low impedance, making it very economical.

[Brief explanation of drawings]

FIG. 1 is a block configuration diagram of a control device for a clothes dryer showing an embodiment of the present invention, FIG. 2a is a characteristic diagram showing changes in drum exhaust temperature in the same clothes dryer,
FIG. 2b is a characteristic diagram showing how the presence or absence of condensed water changes in the clothes dryer, and FIG. 3 is a flowchart showing the operation of the control section. 1... Drum, 2... Heater, 3... Fan, 4... Motor, 5... Condensed water detection device, 6... Temperature detection device,
7...Control unit.

Claims (1)

[Claims] 1 A condensed water detection device and a temperature detection device installed in the exhaust path of the drum, a first degree of dryness corresponding to a drying rate suitable for ironing, and a second degree of dryness corresponding to a standard finish drying rate. and a third degree of drying corresponding to a thorough drying rate, and a setting unit that can set a third degree of drying corresponding to a careful drying rate; is detected as the first degree of dryness,
The condensed water detection device detects the time when the condensed water in the exhaust path of the drum disappears as a second degree of dryness, and the second degree of dryness is detected from the time when the first degree of dryness is reached.
A clothes dryer comprising: a control unit that detects, as a third degree of dryness, the time when a suitable delay time corresponding to the time until the degree of dryness is reached is detected as a third degree of dryness.