JPH0358760B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a clothes dryer that heats and dries clothes that have been washed using a petroleum solvent.

(b) Conventional technology The flash point of petroleum-based solvents is approximately 40°C, and when drying at high temperatures, measures such as drawing in outside air and releasing the vaporized solvent to the outside are necessary to reduce the risk of explosion. It is necessary (see Utility Model Application Publication No. 190192/1983).

Therefore, it has been considered to send a large amount of air to the heater and supply low-temperature drying air to the drying chamber to perform drying operation while avoiding dangers such as explosions.

(c) Problems to be solved by the invention However, if the filter in the circulation path becomes clogged and the amount of air blown decreases, the temperature of the drying air increases, and the danger of explosion etc. still exists.

The present invention is intended to accurately detect a decrease in the amount of air flow in a clothes dryer using a heater that supplies steam or the like intermittently, and to reliably prevent dangers during such low-temperature drying. be.

(d) Means for solving the problem The means for solving the problem according to the present invention consists of a drying chamber containing clothes washed with a petroleum solvent, a heater that supplies steam or the like intermittently, and a filter. a fan that circulates the drying air heated by the heater into the drying chamber; a temperature measuring means that measures the temperature of the pulsating drying air; a period measuring section that measures the pulsation period based on the measured temperature; This configuration includes a cycle comparison section that compares and determines whether the cycle is longer than a reference cycle, and a safety control section that performs control such as stopping the heater etc. based on the comparison output.

(E) Effect When the temperature of the dry air heated intermittently by the heater is measured, it becomes a substantially constant pulsating waveform, and its period is also fixed, for example, 10 seconds. Here, if the air flow rate decreases due to a clogged filter or the like, the pulsation waveform becomes slower as the temperature decreases, resulting in a longer cycle. For example, the time interval (one or more cycles or half cycles) at which a temperature measuring means consisting of a thermistor measures the temperature to be controlled, for example 40°C, is measured by the derivative synchronous measuring section of the microcomputer, and this measurement result is sent to the microcomputer. Input to the period comparison section. This cycle comparison section uses ROM (read-only memory).
The reference period stored in advance is recalled. Here, when the measurement period becomes longer than the reference period, a command to perform safety control is output to the safety control section in the microcomputer, and the safety control section then takes actions such as stopping the steam supply or opening the external exhaust port. Let it be executed.

(F) Embodiment The following is a description based on the drawings. The body 1 of a dry cleaner that sequentially executes washing (rinsing), deliquid removal, drying, and deodorizing processes, or a clothes dryer that executes only drying and deodorizing processes. has a drying room (or a drying room that also serves as a washing room) 2 for storing clothes washed with petroleum-based solvents, and an air circulation path 3 with an inlet and an outlet at both ends communicating with this drying room 2. , and a condensed solvent recovery tank 4. Also, aircraft 1
A control box 5 containing predetermined electrical components is provided at the top of the device, and operation knobs including a reset button 6 and an indicator light 7 such as an LED are provided at the front of the top. A buzzer is also provided if necessary.

Here, a motor-driven rotating drum 8 that rotates at a low speed during the drying process is provided in the drying chamber 2, and a removable filter 9, a fan 10, and a cooler to which cold water is supplied are provided in the circulation path 3. 11. Heaters 12 to which steam is intermittently supplied are arranged in this order. The solvent, which has been cooled by the cooler 11 and condensed and liquefied, flows out into the recovery tank 4 via the outlet section 13. At a downstream position of the heater 12 in the circulation path 3, a temperature measuring means 14 consisting of a thermistor measures the temperature of the heated dry air.

The electrical components installed in the control box 5 are configured as a control circuit centered around a microcomputer 15, and a circuit diagram of this circuit is shown in FIG.
The microcomputer 15 to which the control time signal is input is
ROM16, RAM17, CPU18, I/O19
It constitutes an OFF counter 20, a period measurement section 21, a period comparison section 22, a safety control section 23, and an alarm control section 24, which will be described later. The temperature measuring means 14
The temperature measured by is read by the microcomputer 15.

The drying operation time and operating procedure are stored in the ROM 16 in advance, and when the start key is operated, the third
Operation begins as shown in the flowchart in the figure. During operation, the rotating drum 8 rotates slowly and the fan 10 is driven to circulate a large amount of air. Also,
Cooling water is continuously supplied to the cooler 11, and the heater 1
2. Supply steam intermittently.

Thus, a large amount of low-temperature drying air is constantly fed into the drying chamber 2, enters the clothing, and vaporizes the solvent, while the temperature of the drying air is read by the microcomputer 15. This temperature pulsates because the steam supply to the heater 12 is intermittent (see FIG. 4). The microcomputer 15 starts measuring temperature and time, and when the measured temperature reaches the control temperature (for example, 40 degrees Celsius) during the operation time, it turns off the heater 12 and adds 1 to the contents of the counter 20 to record the current value. The time (T _OFF(o) ) is memorized. Thereafter, each time the measured temperature decreases or rises from the control temperature and reaches it, the heater 12 is turned on and off, and the time when it was turned off is stored in sequence.

The period measuring section 21 of the microcomputer 15 detects the period of the heater 12.
When the number of OFF times, that is, the counter contents becomes 2 or more,
The period (T) is calculated by subtracting the previous time (T OFF _{(o) ) from the current time (T OFF (o+1)} ), and is output to the period comparison section 22 . The period comparison section 22 is
Reference period (T ₀ ) from ROM16 (for example, 10 seconds)
is called and compared with the measurement period (T), and (T)≦
No output is made during (T ₀ ).

The temperature characteristics when the air flow is sufficient are shown by the solid line in Figure 4, and the vaporized solvent that comes out of the clothes due to the smooth penetration of the low-temperature drying air is cooled in the cooler 11, condensed, and liquefied. It is collected from the derivation section 13 into the tank 4.

On the other hand, if the filter 9 becomes clogged and the air flow rate decreases, although the drying air temperature increases in the same way when steam is supplied, the degree of decrease in the drying air temperature decreases when the steam supply is interrupted, that is, the temperature reduction characteristics become slower. . As a result, the period (T) measured by the measuring unit 21 for each control temperature becomes longer (see the dotted line in FIG. 4). When the measurement period (T) exceeds the reference period (T ₀ ), the period comparison section 22 outputs an output to the safety control section 23 of the microcomputer 15 to execute safety control. That is, the safety control unit 23 stops the supply of steam to the heater 12 and drives the torque motor 25 to open an external exhaust port (not shown). Puts the operation into a suspended state where time is stopped. Furthermore, the comparison section output causes the alarm control section 24 to flash the indicator light 7 and the buzzer 26.
The alarm is executed intermittently or continuously.

Such safety and alarm control can be canceled by operating the reset button 6, and by operating the start key after cleaning or replacing the filter 9, the operation can be continued for the remaining time.

In this embodiment, when the measurement period (T) exceeds the reference period (T ₀ ), so-called abnormality processing is immediately performed. However, in order to avoid malfunction, the state of (T)>(T ₀ ) is maintained for a certain period of time ( For example, abnormality processing may be performed when the error continues (for example, for 3 minutes).

(G) Effects of the Invention According to the present invention, by measuring the cycle of intermittent heating conditions, it is possible to detect a decrease in air flow rate due to filter clogging, etc., and detect when the drying air temperature exceeds the flash point of the solvent. It is possible to prevent the risk of explosion and provide an extremely safe clothes dryer.

[Brief explanation of drawings]

FIG. 1 is a control circuit diagram of a clothes dryer according to the present invention, FIG. 2 is a front sectional view, FIG. 3 is a flowchart for explaining the operation, and FIG. 4 is a temperature characteristic diagram. 2... Drying room, 3... Circulation path, 9... Filter, 10... Fan, 11... Cooler, 12...
Heater, 14... Temperature measuring means, 15... Microcomputer, 21... Pulsation period measuring section, 22... Period comparison section, 23... Safety control section.

Claims (1)

[Claims] 1 A drying chamber containing clothes washed with a petroleum solvent, a heater that supplies steam or the like intermittently, and a filter that circulates drying air heated by the heater to the drying chamber. a temperature measuring means for measuring the temperature of the pulsating dry air; a period measuring section for measuring the pulsation period based on the measured temperature; a period comparing section for comparing and determining whether the measurement period is longer than the reference period; 1. A clothes dryer for dry cleaning, comprising a safety control section that performs controls such as stopping the heater etc. based on the output.