JPH02249599A - How to control a clothes dryer - Google Patents

Abstract

PURPOSE:To perform reliable detection of completion of drying irrespective of a difference in capacity of a heater and a load amount and to improve drying efficiency by a method wherein, before, after the starting of a heating process, an exhaust gas temperature is increased to a given value, the water removing motion of a cooling part is not started. CONSTITUTION:When hot air is forced to flow in a rotary drum 3 and a heating process is carried out, before an exhaust gas temperature is increased to, for example, approximate 70 deg., a water removing (dehumidifying) function is not worked. The exhaust gas temperature is detected by a thermistor 8 for detecting an exhaust gas temperature mounted in an air circulating route 4. In the water removing (dehumidifying) process, since, through the feed of water to a cooling and water removing part 6, hot air is cooled, water is removed and temperature is temporarily reduced. In which case, a specified time (mask time) is set in order that completion of drying and erroneous decision are prevented from occurring, and the starting of measurement of the coefficient of a temperature change is suppressed. When the mask time passes, a constant rate period (a part B) is clearly expressed. In which case, calculation of the coefficient of a temperature change is started. This method makes a change from a constant rate period to a damping period clear, and provides reliability of detection of completion by effecting decision of completion of a drying process.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industry" - Second Field of Application] The present invention relates to a method for controlling a clothes dryer in which exhaust gas from a drying chamber is dehumidified by heat exchange, reheated, and returned to the drying chamber.

[Prior Art] An example of a conventional clothes dryer of this type is a drum-type washer/dryer that performs washing, rinsing, and drying in one rotating drum.

As shown in Japanese Patent Publication No. 62-6840, for example, the clothes dryer is controlled by operating a water removal function (dehumidification function) at the same time as drying starts (heater operation starts).

FIG. 4 shows the drying process by such a control method, with the drying time plotted on the X-axis and the exhaust gas temperature plotted on the Y-axis. In the figure, the period from the start of drying (0) to the predetermined time t is a preheating period in which the temperature inside the drying chamber increases during the drying process.
Step 1: The air temperature gradually rises. During this period, the drying efficiency, which is the ratio of the amount of water evaporated from the dried λ·1 object to the power consumption, also gradually increases.

And elapsed time 1. After that, after the exhaust temperature rises to a predetermined temperature by 1 degree (after the preheating period has elapsed), there is a careful period in which drying can be carried out with extremely stable drying efficiency and the exhaust temperature is also stable. Further, after an elapsed time t2, when most of the moisture from the object to be dried is removed, a period of decreasing rate occurs in which the drying efficiency gradually decreases, and the exhaust gas temperature rises.

When it is detected that the exhaust gas temperature has become higher than a predetermined temperature compared to the temperature during the careful period, the drying is terminated, the operation of the fan, heater, etc. in the dryer is stopped, and the automatic mode of operation is performed. That's what I do.

[Problems to be Solved by the Invention] As mentioned above, the conventional dryer control method starts water removal (dehumidification) at the same time as drying starts, and also detects the end of drying based on the exhaust temperature during the careful period and the lapse rate period. Comparison with the exhaust temperature at

Therefore, as shown in FIG.

As b+c) increases and the heater capacity becomes larger, the drying period becomes shorter, but the change curve becomes steeper and the cautious period (period in which the exhaust gas temperature is approximately constant) becomes unclear. For this reason,
Base Q to end drying? There was a problem in which it was difficult to detect the temperature during the caution period when it reached H degrees.

In addition, as shown in Fig. 6, the load amount (laundry amount) (a''
The exhaust gas temperature characteristics during the preheating period also differ depending on b- and c-. That is, when the load amount is small (there are few laundry items), the change curve becomes steep because drying is also performed in a short time. Therefore, since there is no clear caution period, there is a problem in that it is difficult to detect the reference temperature for ending the process, similar to when the heater input is large.

Furthermore, as shown in Fig. 7, the heating state differs depending on whether the water removal function (dehumidification function) is in operation or not (a, b''). This results in cooling and delays the rise in tn degree of the exhaust hot air.

Therefore, if the water removal function is operated at the same time as drying, there is a problem that the exhaust gas level increases slowly during the preheating period, and the drying efficiency also deteriorates.

The present invention has been made with the aim of solving the above-mentioned problems, and is capable of stably detecting the completion of drying regardless of differences in heater capacity and load amount, and is efficient. The present invention relates to a method of controlling a clothes dryer that can perform drying.

[Means for Solving the Problem] In order to achieve the above-mentioned object, the present invention
l: A method for controlling a clothes dryer in which drying is performed by exchanging air with air in a cooling section to remove moisture, and then reheating it with a heater and returning it to the drying chamber, wherein the heater and the heater A heating step 1' in which a fan is operated to send heated air into the drying chamber, and after the start of the heating step, the temperature of the pl-heat from the drying chamber is increased to a predetermined temperature.
? , and then a water removal step in which a cooling unit is operated to cool and remove water from the heated air, and after a predetermined time has elapsed after the water removal step has been started, exhaust air 11 from the drying chamber is removed. a temperature detection step of starting the operation of a temperature detection means for detecting the rate of change in temperature; and an end detection step of determining the end of drying based on the information detected by the temperature detection means and stopping the fan, heater, etc. It is characterized by containing.

[Function] The present invention starts the water removal operation (water removal process) of the cooling unit only after the exhaust gas temperature rises to a predetermined temperature after the start of the heating process, thereby reducing the IA humidity temperature increase rate during the preheating period. can be improved and create a stable cautious period based on the start. After the start of this water removal process, the detection of the rate of change in exhaust gas temperature is started a predetermined time after entering the caution period, so the temporary temperature drop due to the start of water removal may be mistakenly determined to be a dry path γ. Never. Therefore,
It is possible to detect the temperature that is the standard for the end of drying without misperception, and to perform efficient drying.

[Example] An example of the present invention will be described based on FIGS. 1 to 3.

As the clothes dryer used in the present invention, there is, for example, a Y711 construction as shown in FIG.

In the figure, 0) is a casing that houses the washer/dryer main body mechanism, and (2) is an outer tank installed inside the casing (1), which stores water during washing and rinsing. (3) is a rotary drum that is rotatably supported in the outer tank (2) and has a large number of small holes (3a), and performs washing and drying operations inside the drum by rotation. .

(4) is an air circulation path provided for blowing warm air into or discharging warm air into the rotating drum (3) during the drying operation. (5) is a fan provided in the middle of the air circulation path (4), which circulates warm air heated by the heater (7) within the path (4). (6) is a cooling water removal section (6) provided in the middle of the air circulation path (4), which cools the hot air containing moisture and removes water.

Note that cooling water (Jl) is supplied to the cooling water removal section (6), and water flowing from the cooling water removal section (6) is discharged to the outside.

Next, the water removal (dehumidification) action is carried out by first sending out warm air from the fan (5), heating it with the heater (7), and hitting the damp laundry in the rotating drum (3), causing the air to flow through the small holes (3a). The moist warm air passes through the path (4) and is guided to the cooling water removal section (6) where it is cooled. Water is supplied to the cooling water removal section (6) to cool the hot air.

This cooling lowers the saturated water vapor pressure of the hot air, causing supersaturated water to condense and be discharged to the outside.

The cooled and water-removed air is then drawn into the fan (5) again, heated by the heater (7), and heated by the rotating drum (3).
).

The present invention controls the drying process in a dryer equipped with such functions, determines when to finish based on the exhaust temperature, and automatically stops each function.

One embodiment of the present invention has a feature in this control process at the time when the water removal operation starts.

That is, as shown in FIG. 1, after a predetermined operation such as dehydration is completed, the drying function is operated (S). This drying operation is performed by operating the fan (5) and heater (7) to cause warm air to flow into the rotating drum (3). That is, it means the start of the heating process.

Then, in (S2), the set temperature, for example, the exhaust IH degree is set to 7.
The water removal (dehumidification) function is operated only when the temperature reaches about 0 degrees (S3).

In addition, FIG. 3 shows the exhaust temperature characteristics in this example, and the characteristics of a and bSc in the figure are similar to the characteristics of a, b, and c in FIG. 5 when the heater input is a>b>C. It represents a case where there is a size relationship.

Also, as shown in the figure, the time it takes for the exhaust temperature to reach about 70 degrees increases as the heater power decreases, T, → T2
→T3 and gradually become longer.

The exhaust temperature is detected by an exhaust temperature detection thermistor (8) provided in the air circulation path (4).

The operation of the water removal (dehumidification) function is started by starting the supply of water to the cooling water removal section (6). As the water removal (dehumidification) function starts to operate, the warm air is cooled down.
As the water is removed, the temperature temporarily decreases as shown in FIG. 3 (portion A of each curve).

Therefore, in order to avoid detecting this temperature drop, that is, a rate of temperature change exceeding a predetermined value, and erroneously determining that drying is complete, a certain period of time (mask time) must be set (S4) to detect the temperature change rate for determining the end of drying. Change revision 71! The start of + will be postponed. This fixed time (T, A) (mask time) is
This is the time set in advance by predicting the temperature drop time.

As this mask time elapses, the loss rate period (portion B of each curve) is clearly exposed, as shown in FIG. Here, the measurement of the drying end temperature, that is, the calculation of the temperature change rate is started (S5).

As a result, the change from the loss rate period to the decrease rate period becomes clear, and by detecting the rate of change in exhaust gas temperature and determining the end of the drying stage when the temperature rise rate exceeds a predetermined value (S6 ) Completion detection-KI can be as reliable as iW.

According to the above embodiment, even in the case of large heater power a, the change from the cautious period to the decreasing rate period can be made clear, and as a result, erroneous termination judgment or a state in which termination cannot be detected can be prevented. be able to.

[Effects of the Invention] Since the present invention is based on the control method described above, even when the heater has a large capacity and the load ffl is small, a clear caution period appears, and the can be done easily and accurately.

In addition, the exhaust temperature during the preheating period at the start of the drying process can be increased rapidly.
-H, and efficient drying can be performed.

[Brief explanation of drawings]

FIG. 1 is a flow chart diagram according to an embodiment of the present invention;
FIG. 2 is a side sectional view of the clothes dryer used in the present invention;
Fig. 3 is an exhaust temperature-drying time characteristic diagram according to the present invention; Figs. 4, 5, and 6 are exhaust temperature-drying time characteristic diagrams; Fig. 4 is a general characteristic diagram; Figure 6 shows the characteristics depending on the magnitude of the heater input, Figure 6 shows the characteristics depending on the magnitude of the load, and Figure 7 shows the 111 air temperature - 1 - rise characteristics when the dehumidification function is activated and not activated. It is. In the figure, (1) is the casing, (2) is the outer tank, and (3) is the casing.
) is a rotating drum, (3a) is a small hole, (4) is an air circulation path, (5) is a fan, (6) is a cooling water removal section, (7) is a heater, and (8) is an exhaust temperature detection thermistor. be. In addition, in the figures, the same symbols indicate the same, - or equivalent parts.

Claims (1)

[Scope of Claims] A method for controlling a clothes dryer that performs drying by heat-exchanging exhaust air from a drying chamber in a cooling section to remove moisture, then reheating it with a heater and returning it to the drying chamber. a heating step of operating the heater and a fan that sends the air heated by the heater into the drying chamber; and after the temperature of the exhaust gas from the drying chamber has risen to a predetermined temperature after the start of the heating step, the heating step is performed. a water removal process in which a cooling unit is operated to cool and remove water from the air, and a temperature in which the rate of change in the temperature of the exhaust air from the drying chamber is detected after a predetermined time has elapsed after the water removal process has started. Clothes drying characterized by comprising: a temperature detection step for starting the operation of a detection means; and an end detection step for determining the end of drying based on information detected by the temperature detection means and stopping the fan, heater, etc. How to control the machine.