JPS6126399B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the operation of a clothes dryer that automatically terminates operation while determining the degree of dryness of clothes.

Conventional clothes dryers have a timer that sets the operating time, and when the set time elapses, the operation automatically ends, and the difference between the inlet and outlet temperatures of the drying chamber or the outlet temperature. Measure only
Some devices automatically end operation when the measured value reaches a certain value.

However, when using a timer to set the operating time, it is necessary to change the set time depending on the amount of laundry, type of fiber, dehydration rate, etc.
It was not always easy to set the optimal time.

In addition, if the machine is operated while measuring the difference between the inlet temperature and outlet temperature or only the outlet temperature, the outlet temperature at the end of drying will vary depending on the amount of laundry, so the temperature at the end of operation should be set in advance. If there was no finish, it would not be possible to obtain the desired finish.

In order to eliminate such drawbacks, the difference between the inlet and outlet temperatures is detected during the constant rate period when the outlet temperature is approximately constant, and stored in a microcomputer. A method has been considered in which the drying operation is terminated when the value becomes less than the value obtained by multiplying this stored value by the drying rate. However, if the inlet temperature changes irregularly due to pressure fluctuations of the heating steam that is the heat source, the high temperature side can be kept down to the set temperature by the inlet temperature sensor, but
If the temperature changes to the low temperature side, it cannot be raised to the set temperature. As a result, even if the value stored in the microcomputer is multiplied by the drying rate, it is not reliable whether a desired dry state can be obtained.

The purpose of the present invention is to make it possible to accurately detect the end point of the drying operation even when the temperature on the inlet side does not rise sufficiently. If the side temperature does not reach the set value, the inlet side temperature at that time is re-stored as the set temperature, and thereafter the inlet side temperature is kept constant at the re-stored low temperature. Generally, the drying rate at the end of the constant rate period is approximately 80, regardless of the inlet temperature.
%, even if the set temperature is lowered, the desired dry state can be achieved in the end, although the drying time will be longer.

To explain based on the figure below, 1 is a clothes dryer having a clothes loading door 2 on the front, and above this door there is a main switch 3 for turning on and off the power, and a dryness level at the end of the automatic detection course. A drying degree adjustment knob 4 for adjusting the temperature, a keyboard 5 for course setting, time setting, or temperature setting, a fluorescent display tube 6 for displaying the time, a fluorescent display tube 7 for displaying the temperature, and a heat source for drying. A steam pressure gauge 8 is provided to display the steam pressure. In addition, a drying drum 10 is rotatably provided in a drying chamber 9 formed at the center of the clothes dryer, and a radiator 11 is installed above the drying drum 10.
12 and 13 are divided into three parts, and a bottomed cylindrical filter 14 and an exhaust blower 15 are provided at the bottom. The three-divided radiator 11, 12,
Among 13, one radiator 11 is connected to a steam supply pipe 17 via a first steam valve 16,
The other two radiators 12 and 13 are connected to the steam supply pipe 17 via a common second steam valve 18, and from this steam supply pipe 17 a humidification pipe 19 is connected.
The humidifying pipe is branched and its tip opens into the drying chamber 9, and a live steam valve 20 and a manual opening adjustment valve 21 are inserted in the middle of this humidifying pipe. The drying drum 10 is rotated by a motor 24 via pulleys 22 and 23, and the exhaust blower 15 is rotated by another motor 25. As the exhaust blower rotates, air is sucked in through the intake port 26, heated by the radiators 11, 12, and 13, and further enters the drying drum 10 to remove moisture from the clothes before being discharged from the exhaust port 27. . The radiators 11, 12, 13 and the drying drum 1
Inlet temperature detector 28 consisting of a thermistor between 0 and 0
However, on the outlet side of the drying drum 10, an outlet temperature detector 29, also made of a thermistor, is provided. 30 is a printed circuit board that constitutes a control circuit;
A block diagram of this circuit is shown in FIG. The control circuit is mainly composed of a microcomputer, and includes 31 central processing units (in this example,
Built-in RAM. An address bus (12 bits) for specifying the address of the program and a data bus (8 bits) for transferring instructions to the CPU 31 are used to connect the ROM 32 (hereinafter abbreviated as CPU) and the ROM 32 that stores the program. connected. CPU31
ICs 33 and 34 for input/output expansion are connected to the input/output expansion device, so that it can handle a large number of input/outputs. The input of the CPU 31 is a D/D output that outputs the inlet temperature, outlet temperature, and set values of the dryness adjustment knob 4.
3 bits from the A converter 35, a keyboard switch for setting the operating course, time and temperature, and operation start/stop operations, and 4 bits from the course/preset switch 36 for selecting and setting the operating course when the power is turned on. 3 bits from the 50Hz/60Hz specification changeover switch, door switch, and thermal switch 37, 1 bit from the reset circuit 38 for resetting the CPU 31 when the power is turned on, and the square wave voltage of the power supply frequency. There is one bit from the external interrupt circuit 39 which generates and inputs to the external interrupt terminal of the CPU 31. Also,
Outputs from the CPU 31 include outputs to the fluorescent display tube 6 for displaying time, etc., outputs to the fluorescent display tube 7 for displaying temperature, etc., and set values for temperature measurement and dryness adjustment knobs. There are outputs to the D/A converter 35 for reading, outputs to drive the steam valves 16 and 18, live steam valve 20, fan motor 25, drum motor 24, and a buzzer 40.

Here, according to the flowchart in Figure 4,
The operation of the dryer of this embodiment will be sequentially explained. First, when the power is turned on, the reset circuit 38 operates,
The CPU 31 starts executing the instruction stored in the ROM address 32, resets all outputs, and
After clearing the RAM area, input the open/closed state of the 50Hz/60Hz specification changeover switch 37, and select the 50Hz specification.
Decide whether it is a 60Hz specification.

Then, the open/close state of the course preset switch 36 is input, and the time and temperature of the driving course specified by the course preset switch 36 are set. In actual use, commercial steam dryers are often used exclusively for a specific operation course; for example, a dryer exclusively used for clothes washed in an oil-dry washing machine has a time-controlled course. In many cases, only the following programs are used. Therefore, the course preset
By specifying the time control course program in advance with the switch 36, the time control course program is set when the power is turned on, and operation can be started simply by pressing the start key on the keyboard 5, making operation extremely easy. This is because it has the advantage of becoming

Here, the setting of the driving course will be briefly explained. When the power is turned on, the operation course and program number are set by the above-mentioned course/preset switch 36, so the data of the inlet set temperature, outlet set temperature, hot air set time, and cold air set time written in advance in the ROM 32 is stored. CPU31
The data is written to a predetermined area reserved in the internal RAM. In addition, an area is reserved in the RAM to store data on hot air operating time and cold air operating time, and the remaining operating time or total operating time is stored. The driving course can be set using the keyboard 5, and once the driving course and program number are set using the keyboard, the operation will start in the same way as when the power is turned on.
Data in ROM32 is written to RAM. Further, the settings other than the hot air setting time and setting temperature of the automatic detection course can be changed using the keyboard 5, and a part of the drying program prepared in advance can be changed.
Operation is performed based on data in RAM.

When the initial setting at the time of power-on is completed, the operation routine starts from the flowchart in FIG. 4. First, 1 is input by the external interrupt circuit 39.
It counts time in seconds and is used as a reference for output control during operation or to count operation time. Next, the D/A converter 35 reads the inlet temperature, the outlet temperature, and the setting value (X) of the dryness adjustment knob 4, and the fluorescent display tubes 6 and 7 display the time and temperature. The input on the keyboard switch 5 is checked, and if there is an input, a process corresponding to the input is performed, for example, when an automatic detection course is pressed, an automatic detection course is set. When the start key (included in the keyboard switch 5) is pressed after the course has been completely set, the state of the door switch 37 is input, and if the door is closed, the operation mode is entered.

The processing of the keyboard switch 5 is shown in FIG.
This is carried out according to the flowchart shown in FIG.
First, it identifies which key was pressed and performs the processing corresponding to each key. The automatic detection key is
Applications will not be accepted if they are in the middle of an automatic detection course, not only while driving or when an abnormality has occurred, but also if they are stopped midway. This is the same for other course keys (however, the live steam input key is accepted even during operation. This will be explained later), and this is to prevent you from easily changing from the automatic detection course to another course. This is essential for normal driving by preventing the driving data of the automatically detected course from being cleared due to accidentally pressing another course key while driving the course. However, it is possible to change from the automatically detected course before the start of operation. In addition, when the user wishes to change from the automatic detection course to another course, by pressing the stop key again from the mid-stop state,
The CPU 31 is returned to the state before the start of operation and can be changed. By performing the above-mentioned processing, the keyboard switch 5 can be activated during a stop in the middle of an automatic detection course, where it is important to maintain driving data.
It is possible to prevent erroneous operation, and even if you want to consciously change the course, you can easily change it by pressing the stop key twice, so there is no need to provide a special key for changing the course. big.

The start key starts operation before starting operation or from a stopped state, but at this time, if the door is open or the settings are not completed, the operation will not start. Furthermore, when the outlet temperature setting is higher than the inlet temperature setting, an alarm is generated to notify of a temperature setting error. In the steam dryer of this embodiment, as is clear from FIG. 6, the outlet temperature cannot be higher than the inlet temperature, so if the outlet temperature is set higher than the inlet temperature, Normal drying operation may not be possible. Therefore, if you check the set values when you press the start key and issue an alarm if there is an inconvenience, you can reset the settings and restart immediately without driving unreasonably. It's convenient.

During hot air operation, the fan motor 25 and drum motor 24 are driven to constantly rotate the fan 15 and rotate the drum 10 at a cycle of 15 seconds N-2 seconds FF. Further, the steam valves 16 and 18 are opened and closed according to the set values of the inlet temperature and the outlet temperature to control the radiators 11, 12 and 13 as shown in the flowchart of FIG. 4E.

When both the outlet temperature and inlet temperature are below the set temperature,
Either the steam valves 16, 18 are opened to raise the temperature of the hot air by the radiators 11, 12, 13, but at the start of operation, the steam valves 16, 18 are opened depending on the set value of the inlet temperature. By changing the combination of radiators 11, 12, and 13, the number of stages of the radiators 11, 12, and 13 is changed.

In the case of this embodiment, when the inlet set temperature is 131°C or higher, both steam valves 16 and 18 are opened, and the radiators 11, 12, and 13 are set to three stages, so that the inlet set temperature is 96°C or higher. Steam valve 1 when the temperature is below 130℃
Open only one valve of 8 and open radiators 12 and 13.
When the set inlet temperature is 95° C. or lower, only one steam valve 16 is opened, and the radiator 11 is set to one stage.

In addition, with steam dryers, the steam pressure may drop due to the relationship with other steam consuming equipment, making it impossible to reach the set inlet temperature. , If the temperature is lower than the inlet set temperature minus 5 degrees, start operation 3.
After 1 minute and 4 minutes, the steam valve is opened and closed to increase the number of radiators 11 by one stage. Furthermore, if the minimum inlet temperature determined by the inlet temperature setting has not been reached 5 minutes after the start of operation, an alarm is generated to notify that the temperature is insufficiently increased. In the case of this example, when the inlet set temperature is 131°C or higher, the minimum inlet temperature is 100°C,
When the inlet set temperature is 106°C or higher, the minimum inlet temperature is 70°C, and when the inlet set temperature is 50°C or higher, the minimum inlet temperature is 50°C.

By controlling as described above, even if the steam pressure decreases, the time required to reach the set inlet temperature will not be prolonged, and when the main valve of the steam supply pipe 17 is closed, the minimum inlet temperature will not be reached. This is very convenient because an alarm will be issued 5 minutes after the start of operation to notify you of the abnormality.

When the inlet temperature or outlet temperature is above the respective set temperature, the steam valves 16, 18 are closed and do not open until both the inlet and outlet temperatures are lower than the control temperature.

However, since the outlet temperature setting of the automatic detection course defines the upper limit of the outlet temperature, if the outlet temperature remains higher than the outlet temperature setting for 5 seconds, the hot air operation is ended and the cold air operation is started.

During hot air operation after 3 minutes of operation, if the inlet temperature remains 30 degrees or more above the inlet set temperature for 10 seconds, or the outlet temperature remains 15 degrees or more above the outlet set temperature for 10 seconds. Sounds an alarm to notify of excessive temperature rise.

The automatic detection course determines the end time of the hot air operation by utilizing the fact that the outlet temperature changes as shown in FIG. 5 when the inlet temperature is kept constant. After a while after starting operation, there is a period when the outlet temperature becomes almost constant (this is called the constant rate period). The automatic detection course is based on the difference between the inlet temperature and outlet temperature during this constant rate period (this is defined as T).
The difference between the inlet temperature and outlet temperature is the dryness adjustment knob 4.
The operation is stopped when the value x (0.5≦x≦1) and the reference value T becomes smaller than the product xT.

As shown in the flowchart in FIG. 4F, in this embodiment, the reference value T is read in the following manner. After the start of operation, the difference between the inlet temperature and outlet temperature every 45 seconds is stored in RAM, and the difference between the inlet temperature and outlet temperature at that time is smaller than the difference between the inlet temperature and outlet temperature 45 seconds before. If the inlet temperature has previously reached the inlet set temperature _t1 , the difference between the inlet temperature and the outlet temperature when the inlet temperature matches the inlet set temperature immediately after this is set as T (fifth (see figure). If the inlet temperature t' has not reached the inlet set temperature _t1 by then, immediately set the difference between the inlet temperature and the outlet temperature as T, and
The inlet temperature t' at that time is then stored in place of the inlet set temperature stored in the microcomputer and subsequent control is performed. (See Figure 6) At this time, if the difference between the inlet temperature and the outlet temperature does not become smaller than the difference between the inlet temperature and the outlet temperature 45 seconds before, even after 5 minutes have passed after the start of operation, the inlet set temperature has been reached. Depending on whether or not there is a problem, T is read in the same manner as described above. In addition, if the inlet temperature does not match the inlet set temperature even if the T readable state continues for 5 minutes, the inlet temperature at this time will be used as the inlet set temperature from now on, and the difference between the inlet temperature and the outlet temperature will be set as the inlet temperature. (compensation for T reading).

To read the difference T between the inlet temperature and outlet temperature during the constant rate period as described above, as shown in Figure 5,
In reality, the inlet temperature fluctuates around the inlet control temperature, so when the constant rate period begins, the difference between the inlet temperature and the outlet temperature when the inlet temperature matches the inlet control temperature is set as T. This is because the variation in drying rate after the end of the operation is reduced and highly accurate control can be performed. Also, there is a slight lack of steam pressure,
If the constant rate period is entered before the inlet set temperature has been reached, the inlet temperature at the time T is read will be used as the inlet set temperature from now on, as described above, so the steam pressure will rise during operation. Since the inlet temperature is also controlled to be kept constant, there is no possibility of false detection of completion of drying.

After reading T, x (0.5
≦x≦1) and the stored T, and compare this value xT with the difference between the inlet set temperature and the outlet temperature, and find out that the difference between the inlet set temperature and the outlet temperature is smaller. When held for 20 seconds, hot air operation ends and changes to cold air operation. As shown in Figure 5, the inlet temperature fluctuates around the control temperature, so if control is based on momentary inlet temperature data, the drying rate at the end of the drying operation will vary widely. This causes the inconvenience of putting it away. However, as in this embodiment, by regarding the inlet set temperature as the inlet temperature and controlling based on the difference between the inlet control temperature and the outlet temperature, the variation in drying rate can be reduced. Further, since the fluctuation in the outlet temperature is not so large, there is no problem in practice.

As mentioned above, when the drying chamber enters the constant rate period and the difference between the inlet set temperature and the outlet temperature is read into the microcomputer, if the inlet temperature has not yet reached the set value, the operation is performed without changing this set value. If you continue,
Afterwards, when the steam pressure in the radiator recovers and the amount of heat generated increases, the outlet temperature also rises, making it impossible to obtain the desired drying condition that was initially set. replaces the actual inlet temperature at that time with the set temperature, and thereafter maintains the inlet temperature constant around that temperature, so the outlet temperature is also maintained at a constant rate.
It takes a long time to achieve the desired dry state.

[Brief explanation of the drawing]

The drawings all relate to an embodiment of the method for controlling the operation of a clothes dryer according to the present invention, and FIG. 1 is a front view of the clothes dryer;
Figure 2 is a vertical side view, Figure 3 is a block diagram related to information transmission, Figure 4 A to A are flowcharts, and Figure 5 is a flowchart.
The figure is a graph showing changes in inlet temperature and outlet temperature when the inlet temperature reaches the set temperature, and FIG. 6 is a graph when the set temperature is not reached. 10... Drying drum, 11, 12, 13... Radiator, 28... Inlet temperature detector, 29... Outlet temperature detector.

Claims (1)

[Claims] 1. Install an inlet temperature detector on the inlet side of the drying chamber and an outlet temperature detector on the outlet side to measure the inlet side temperature and the outlet side temperature, and reduce the difference between the inlet side temperature and the outlet side temperature. It is determined that the constant rate period has entered when the rate changes to A method for controlling the operation of a clothes dryer, comprising controlling the drying operation based on a set temperature and a predetermined outlet side temperature.