JPH0557880B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a clothes dryer in which a heat exchanger is provided in a hot air circulation path to dehumidify the circulating air.

BACKGROUND TECHNOLOGY A conventional clothes dryer of this kind has a temperature sensor installed on the inlet side of a heat exchanger in a hot air circulation path, and the constant rate drying period is determined based on the temperature change of this temperature sensor. In other words, as shown in Figure 5, the temperature at the inlet of the heat exchanger continues to rise at the beginning of operation, and after a certain period of time, there is a constant rate drying period in which drying operation continues with the temperature rising stopped. Therefore, the constant rate drying period can be determined by detecting a state in which the temperature rise has stopped. The reason for determining the constant rate drying period is to set the drying end point based on the end point of the constant rate drying period.

Problems to be Solved by the Invention However, in the conventional configuration, when the temperature around the clothes dryer changes, the temperature detected by the temperature sensor also changes up or down. This is because outside air is introduced into the heat exchanger for dehumidification, and by exchanging heat between this outside air and the hot circulating air, the temperature at the inlet of the heat exchanger changes.

As mentioned above, if the temperature changes due to the ambient temperature, the temperature during the constant rate drying period will also change, so when detecting the constant rate drying period using the characteristic that the temperature is constant, determine the constant rate drying period. It was difficult.

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a clothes dryer that accurately and easily determines the constant rate drying period even when the ambient temperature changes.

Means for Solving the Problems In order to achieve the above object, the present invention includes a first temperature sensor that detects the temperature at the inlet of a heat exchanger arranged in a hot air circulation path and that dehumidifies the circulating air; a second temperature sensor that detects the temperature at the outlet of the exchanger; a temperature difference calculation section that calculates a temperature difference between the temperatures detected by the first temperature sensor and the second temperature sensor; and this temperature difference calculation section. a storage unit that stores the temperature difference calculated by the temperature difference calculation unit; and a temperature difference change that calculates the amount of temperature difference change per time based on the temperature difference calculated by the temperature difference calculation unit and the temperature difference stored in the storage unit a certain time ago. and a constant rate drying period determining section that compares the value of the temperature difference change amount calculating section with a predetermined value to determine a constant rate drying period, and the constant rate drying period determining section During a period in which the value of the change amount calculating section is approximately zero, it is determined to be a constant rate drying period and the drying operation is controlled.

Effect According to the above configuration, the first temperature sensor is arranged in the hot air circulation path and detects the temperature at the inlet of the heat exchanger that dehumidifies the circulating air, and the second temperature sensor is arranged in the hot air circulation path and detects the temperature at the outlet of the heat exchanger. a temperature sensor, and a temperature difference calculation unit that calculates a temperature difference between the temperatures detected by the first temperature sensor and the second temperature sensor, and further includes a temperature difference calculation unit that calculates the temperature difference calculated by the temperature difference calculation unit. A temperature difference calculation section that calculates the amount of change per hour is provided, so even if the ambient temperature changes and the temperature difference calculated by the temperature difference calculation section changes, the amount of change in the temperature difference can be calculated. This makes it possible to always output a constant value of zero during the constant rate drying period, and it is possible to accurately determine the constant rate drying period regardless of the difference in ambient temperature.

Examples Examples of the present invention will be described below in Figures 1 to 4.
This will be explained using figures.

In FIG. 1, 8 is a hot air circulation path, in which a heat exchanger inlet 9 and a heat exchanger outlet 10 are provided. The heat exchanger dehumidifies the hot air circulation path 8, and performs dehumidification by exchanging heat between the outside air and the hot and humid air in the hot air circulation path. A first temperature sensor 1 is provided at the heat exchanger inlet 9;
A second temperature sensor 2 is provided at each heat exchanger outlet 10 .

The temperature changes at the heat exchanger inlet 9 and the heat exchanger outlet 10 during operation of the clothes dryer are as shown in T1 and T2 shown in FIG. 2, respectively. This state is detected by the first temperature sensor 1 and the second temperature sensor 2, and the detected temperature of each temperature sensor 1, 2 is determined by the time division switching unit 3 in the arithmetic processing storage unit 11, which is the control unit. The temperature difference calculation section 4 calculates the temperature difference between T1 and T2 shown in FIG. 2, obtains the result of the temperature difference (T1-T2) shown in FIG. Memorize temperature differences.

The temperature difference calculation unit 6 includes the temperature difference calculation unit 4.
The amount of change in temperature difference per hour is calculated from the temperature difference calculated in step 1 and the temperature difference stored in the storage unit 5 a certain time ago. The result calculated by the temperature difference change amount calculation unit 6 is as shown in FIG. 4, and the calculated result becomes almost zero during the constant rate drying period. The constant rate drying period determining section 7 compares whether the amount of change calculated by the temperature difference change amount calculating section 6 is approximately zero, and if it is approximately zero, it is determined that it is a constant rate drying period.

As described above, even if the ambient temperature changes and the temperature difference calculated by the temperature difference calculating section 4 changes, by calculating the amount of change in the temperature difference, a constant value of zero is always maintained during the constant rate drying period. It can be output. Therefore, even if the ambient temperature changes and the temperature difference between the inlet and outlet of the heat exchanger changes, the amount of change in temperature difference that determines the constant rate drying period remains constant at almost zero, so it is not affected by the ambient temperature. This means that the constant rate drying period can be determined using a value that will not change, and the constant rate drying period can be accurately determined regardless of changes in ambient temperature.

Effects of the Invention As is clear from the above examples, in the present invention,
a first temperature sensor that detects the temperature at the inlet of a heat exchanger that is arranged in the hot air circulation path and dehumidifies the circulating air; a second temperature sensor that detects the temperature at the outlet of the heat exchanger; and a temperature difference calculation unit that calculates the temperature difference between the temperatures detected by the temperature sensor and the second temperature sensor, and further calculates the amount of change per unit time of the temperature difference calculated by the temperature difference calculation unit. A temperature difference calculation unit is provided, so even if the ambient temperature changes and the temperature difference calculated by the temperature difference calculation unit changes, the change in temperature difference can be calculated to ensure constant drying during the constant rate drying period. It can output a constant value of zero, making it possible to accurately determine the constant rate drying period regardless of ambient temperature differences.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a control section of a clothes dryer according to an embodiment of the present invention, and FIG. 2 is a diagram showing temperature changes at the inlet and outlet of the heat exchanger during operation of the clothes dryer.
Figure 3 is a diagram showing changes in the temperature difference between T1 and T2 in Figure 2, Figure 4 is a diagram showing the amount of change in the temperature difference in Figure 3 over a certain period of time, and Figure 5 is a diagram showing a conventional clothes dryer. FIG. 3 is a diagram showing temperature changes during operation. DESCRIPTION OF SYMBOLS 1...First temperature sensor, 2...Second temperature sensor, 4...Temperature difference calculation section, 5...Storage section, 6...
...Temperature difference change calculation section, 7. Constant rate drying period determination section, 8. Hot air circulation path.

Claims (1)

[Claims] 1 A first temperature sensor that detects the temperature at the inlet of a heat exchanger that is arranged in the hot air circulation path and performs dehumidification of the circulating air, and a second temperature sensor that detects the temperature at the outlet of the heat exchanger.
a temperature sensor, a temperature difference calculation unit that calculates a temperature difference between the temperatures detected by the first temperature sensor and the second temperature sensor, and a storage unit that stores the temperature difference calculated by the temperature difference calculation unit. , a temperature difference change amount calculation unit that calculates a temperature difference change amount per time based on the temperature difference calculated by the temperature difference calculation unit and the temperature difference stored in the storage unit a certain time ago; and the temperature difference change amount calculation unit. and a constant rate drying period determination section that compares the value of the constant rate drying period with a predetermined value to determine a constant rate drying period, and the constant rate drying period determining section determines a period in which the value of the temperature difference change calculation section is approximately zero. A clothes dryer that determines that it is a constant rate drying period and controls the drying operation.