JPH0246898A - Drying device - Google Patents

Abstract

PURPOSE:To judge the clogging of a filter by calculating the standard temperature of the drying air before and after the heating by heaters from the other standard temperature and comparing said calculated temperature weth the detected temperature. CONSTITUTION:A thermistor 32 detects the temperature Tb of the drying air before the heating by heater 18 and 19, and a thermistor 33 detects the temperature Tc of the drying air after heating. A current transformer 65 detects the electric current value which flows in the heaters 18 and 19, and a microcomputer 54 calculates the heating value Q of the heater from this current value and calculates the standard value of one of the temperature Tb and the temperature Tc according to the equation (I) from the other, ard judges the clogging of a filter on the basis of the result of the comparison between the standard temperature of one of the temperature Tb and Tc and the other temperature.

Description

[Detailed description of the invention] (b) Industrial application fields The present invention relates to a dryer for clothes, etc.

(B) Conventional technology As a conventional example, in a dryer that uses a positive temperature characteristic heater (PTC heater) as a heat source, a clogging indication is made in correlation with the current change of the PTC heater corresponding to a clogging of the filter. Such a structure is disclosed in Japanese Patent Publication No. 57-42360 (DO6F58/28).

That is, as the clogging of the filter increases, the intake air decreases and the amount of heat generated by the PTC heater decreases as shown in FIG. 10. Therefore, clogging is detected by the change in the current of the PTC heater.

(c) Problems to be Solved by the Invention In conventional dryers, the amount of heat generated by the PTC heater changes depending on the intake air temperature and outside air temperature, as shown in Figure 9, but no measures have been taken to address this issue. do not have.

In view of such problems, the present invention aims to accurately detect clogging of filters in dryers.

(D) Means for Solving the Problems The present invention provides a so-called circulation type dryer that includes a temperature detection means B for detecting the temperature Tb of the drying air before being heated by a positive temperature characteristic heater; temperature detection means C for detecting the temperature Tc of the drying air after being heated by the heater; current detection means for detecting the value of the current flowing through the heater; and a heater detecting the above based on a signal from the flow detection means. The thermal IQ of the heater is calculated from the current value, and the other reference temperature is calculated from the value of either the temperature Tb or the temperature Tc according to the following formula, Q-G-C-r(Tc-Tb) However, G: specified air volume, C: specific heat of air, r: specific gravity of air. Control for determining clogging of the dust removal filter based on a comparison result between the base temperature and the other value of the temperature Tb or temperature Tc. It is equipped with means.

(E) Effect For example, when the reference temperature T (Tc) is calculated based on the temperature Tb, it becomes D (Tc) - Tb + Q/<G-C-r),
This reference temperature T (Tc) is a value that takes into consideration the ambient temperature (temperature Tb changes) and the variation in heater characteristics (Q changes), and the value of G is determined by the temperature that passes through the heater when the filter is clogged. If the standard air volume is set, it can be determined whether the filter is clogged by comparing the standard temperature T (C) and the actually measured temperature C.

In other words, if the airflow becomes clogged, the air volume will be lower than G, so the temperature T
If c exceeds the reference temperature T (Tc), clogging has occurred.

Conversely, clogging may be determined by calculating a reference temperature T (Tb) based on the temperature Tc and comparing this reference temperature T (Tb) with the measured temperature Tb. is the temperature T
If b falls below the reference temperature T (Tb), it means that the tube is clogged.

(f) Example Embodiments of the present invention will be described based on the drawings.

In Figure 4, (1) is a rectangular cylindrical machine frame, (February) a cylindrical drum rotatably supported by a shaft within the machine frame (1), (
3) . . . baffles for agitating clothes formed at regular intervals within the drum; (4) a cylinder attached to the front surface of the drum (2) and forming a clothes inlet (5);・Dac cover (6) is pivotally supported on the front surface of the machine frame (1), and a lid body (7) is attached to the rear surface of the drum (2) for closing the clothing slot (5). (8) is a filter cover that holds the filter (7), (9) is a rear cover that is completely attached to the rear surface of the machine frame (1), and has an intake hole 10) in the center... , has an exhaust hole (11) at the bottom.

(12) moves the inside of the machine t-I-(1) into the drum (2).
) The fan casing is arranged to form a partition into a drying chamber (13) that accommodates the drying chamber (13) and a fan chamber (14). (14) An end plate having an inlet (15) communicating with the
16). A circulating air passage (17) is connected to the lower part of the sliding thing (12>), and the air passage (17) is arranged at the lower part of the drum (2), and the air passage outlet ( 17a) is applied to the discharge port (4a) bored in the cylinder cover (4).(18
) (19) is a positive temperature characteristic heater (PTC heater) disposed at the lower position E in the circulation air passage (17), and (20) is a drain port provided at the bottom of the air passage (17). be.

(21) is a disc-shaped resin double-sided fan, which is coaxially supported in the fan chamber (14) with the support shaft (22) of the drum (2), and circulates radially toward the front side. Feather (23
)... are formed, and cooling vanes (2) are formed on the rear side.
4) is formed. (25) is the double-sided fan (2
1) This is a pulley coaxially formed on the rear surface.

(26) is a drive motor, with drive shafts protruding from both ends, and a small boob J (2) fixed to one drive shaft (26a).
A belt (28) wound around the outer periphery of the drive shaft (2) is connected to the drive shaft (2), and the pulley (25) is connected to a small pulley (29) fixed to the other drive shaft (26b). They are connected via a belt (30).

(31) is a first negative characteristic thermistor disposed on the rear surface of the end plate (16), and (32) is a first negative characteristic thermistor disposed at the inlet of the heaters (18) and (19) of the drying air passage (17). 2 negative characteristic thermistor, (33) a third negative characteristic thermistor disposed at the outlet of the heaters (18) and (19) of the drying air path (17), and (34) a third negative characteristic thermistor disposed at the opening/closing of the lid (6); It is a lid switch that opens and closes in conjunction with each other.

In the above configuration, the material to be dried is put into the drum (2), the drive motor (26) and the heater (18) (L9
), the drum (2) and double-sided fan (21)
rotates. Then, due to the rotation of the circulation blades 23), the air passage outlet (17a) is inserted into the drum (2).
) The drying air heated by the heaters (18) and (19) is injected into the fan chamber (14) from the suction port (15) together with moisture after exchanging heat with the object to be dried. and passes through the drying air passage (17) again to the drum (2).
circulate within. On the other hand, due to the rotation of the cooling blades (24)..., outside air is inlet (10)...→fan chamber (14).
)→exhaust hole (11)→outside of the machine, thereby constantly cooling the double-sided fan 21). Therefore, when the drying air enters the fan chamber (14), it collides with the double-sided fan (21), and the moisture contained in the drying air condenses on the surface of the double-sided fan (21). In this way, the dry air is dehumidified. This dew condensation water is removed from the drying air path (17).
and is discharged from the machine through the drain port (20).

FIG. 5 shows an operation section (35) provided at the lower front of the machine frame (1), in which setting keys for various operation switches and display light emitting diodes are arranged.

That is, (36) is a key for selecting and setting the drying course of type 581 (60 minutes, iron, drying, standard, short time),
LEDs (39) to (43) are arranged in parallel to indicate the setting status.
The setting status changes each time you press the button. Note that the short course is a short drying time of about 10 minutes.

(37) is a start/stop key for the course selected by the course setting key (36).

(38) is a strength switching key for the heaters (18) and (19), and LEDs (44) (45) indicating the setting status are arranged side by side, and the setting status changes each time it is pressed. When set to ``low'', both of the heaters (18) and (19) are energized, and when set to ``weak'', either one is energized.

(46), (47), and (48) indicate the progress status of the course.
ED, (49) will be described later, but the heaters (18) and (19)
), which blinks when clogging is detected, and (50) is a power switch.

FIG. 6 shows a specific circuit diagram of the dryer, which will be explained below.

(51) is a lid switch that interlocks the circuit in conjunction with the opening and closing of the lid body (6>), (52) is a constant voltage circuit, and (53) is a waveform shaping circuit, which converts the AC i voltage of the commercial frequency into a rectangular wave pulse. It is shaped into a microcomputer (hereinafter referred to as Maifun).
(54) and used for time counting. <55
) is a clock pulse oscillation circuit, and the microcomputer (54)
Transmits a reference signal that advances the program within (5)
6) is an initial reset circuit, which is connected to the power switch (50).
When the microcomputer (54) is turned on, the program in the microcomputer (54) is set to an initial state.

(57) is a first temperature detection circuit in which the first thermistor <31) is a part of the configuration, (58) is a second temperature detection circuit in which the second thermistor (32>) is a part of the configuration, (59)
) is a third temperature detection circuit that includes the third thermistor (33) as a part of the configuration, and the thermistor (31) (
32) A comparison circuit (61) compares the value obtained by dividing the 1tEE value of (33) with a resistor and the output from the ladder circuit (60) which generates a staircase wave upon receiving the output from the microcomputer (51).
(62) and (63) are compared, and the comparison output is input to the microcomputer (54). Here, the ladder circuit (60
) are the output ports (a) to (
The ladder output changes stepwise as signals are sequentially output from each output terminal. The microcomputer (54) includes the comparison circuits (61), (62), and
3) is connected and input, the ladder circuit (60
), the respective temperatures are determined based on the output status to them.

(64) is an ED drive circuit composed of the various LEDs (39) to (49), and (65) is the motor (26).
and a current transformer (66) that detects the current flowing in the power supply circuit to which the heater (1g) 09) is connected; It is a D converter.

(67), (68), and (69) are ignited by the output signal from the microcomputer (54), and the motor (26) and heater (
18) A bidirectional cylisk conducts the energizing circuit to (19), and (70) is a buzzer circuit for operation termination and abnormality notification.

Here, since the configuration of the microcomputer (54) is well known, a brief outline will be explained based on FIG. 7.

The microcomputer (54) has a CPU (71), a RAM (7
2), ROM (73), timer mark 74), system bus (75), and input/output boats (76) to (8). The CPU <71) is composed of a control section (82) and an arithmetic section (83), the control section (82) takes out and executes instructions, and the arithmetic section (83) takes out and executes instructions. The RAM (72) performs arithmetic processing such as binary addition, logical operation, increase/decrease, and comparison on data given from input devices and memory in response to control signals from the control unit (82). The ROM<73) is used to store information such as means for operating the dryer, setting conditions for judgment, rules for processing various information, etc. It is something to keep.

FIG. 8 shows the first and second temperature detection circuits (57) (5
8) shows the characteristics of the temperature that can be detected. That is, the first temperature detection circuit (57) of No. 1111 detects the drying temperature containing moisture at the outlet of the drum (2) (solid line in the figure), and the second temperature detection circuit (58) detects the drying temperature containing moisture at the outlet of the drum (2). (17) Heat exchange passing through the inside, detecting the drying temperature after dehumidification (dotted line in the figure), these characteristics vary depending on the quantity and quality of clothing, but this figure is the most common one. The temperature inside the drum and the temperature of the clothes rise until the operating time tz4 (15 minutes) elapses. After that, there is a constant drying period in which the moisture in the clothing evaporates and the temperature difference remains almost constant, and when the moisture content decreases, the temperature difference increases again from this state.

The degree of dryness of the clothes at the point where the temperature difference increases again after the constant drying period is 85 to 90% in terms of drying rate, which is suitable for ironing. After that, there is a decreasing rate drying period in which the temperature difference continues to rise, and when the temperature difference rises to a certain value, the drying rate becomes approximately 100%. Therefore, subsequent operations are wasted.

The operation based on such a configuration will be explained according to the flowchart of FIG.

When the power switch is turned on, the microcomputer (54) first detects the first to third temperature detection circuits (57) and (58).
Based on the information input from (59), the current temperature (the temperature detected by the first temperature detection circuit (57) is Ta, the temperature detected by the second temperature detection circuit (58) is Tb, the third temperature detection The temperature detected by the circuit (59) is Tc) and the current signal from the current transformer (65) is detected (S-1), and the detected temperature and current are transferred to the RAM (72). is stored and updated sequentially.

Next, when the course start key is operated, 10 degrees is set as the reference temperature difference B (S-2), and the motor (26) and heaters (18) and (19) are energized.
-3), Start the course. When the course has started, the temperature Ta and the temperature τb exhibit the characteristics as shown in FIG. Tb) is measured (S-4).

Here, the aforementioned 15 minutes is a value determined based on experiments, and is the time immediately before entering the constant drying period in FIG. 8.

The microcomputer (54) constantly measures the difference between the temperature Ta and the temperature Tb (temperature difference C) while continuing the drying operation, and this temperature difference C is determined during the constant drying period. is almost the same as the temperature difference A, but gradually increases as drying progresses and the lapse rate drying period begins. Therefore, in this embodiment, as a means for estimating the end of drying, the temperature difference C is greater than the temperature difference A than the reference temperature difference B (
10 deg) or more (C≧A+B) (S-5), and when it becomes large or 150 minutes have passed from the start of drying operation, the power to the heater (18) is cut off (S-6 ), the drum (2) is rotated for 10 minutes with cold air to prevent wrinkles (cool down), and then the operation is terminated (S-7)<5-8).

Here, the clogging detection program and clogging notification program, which are the characteristics of this embodiment, will be explained based on FIG. 1 and FIG. 2.

In Figure 1, the clogging detection program (S-9) is
It is constantly executed during drying operation. That is, the microcomputer (
54) is the current value flowing through the motor (26) from the current value detected in (S-1>). The current value I flowing through the heater (18) < 19) is calculated by calculating the current value I flowing through the heater (18) < 19), and based on this current ffi I, the heat 11 Q (Kcal/ff1in) of the heater (18) (19) is calculated. ) is calculated (S
-10), and Q-860V-I f.

Next, the microcomputer (54) processes this thermal iQ and (S-
From the temperature detected in step 1), the ROM (73
), the reference temperature T (Tc) to be detected by the third temperature detection circuit (59) when the filter (7) becomes clogged is calculated (S-11).
.

Q = G −Cr (Tc−Tb)”(1
) However, G (m3/In) is the air volume when it is assumed that the filter (7) is clogged, and is set in advance based on experiments. C (Kcal/ (Kg ・'C))
is the specific heat of air, and r (kg/m3) is the specific gravity of air.

That is, since G, C, and r are constants, T (c) = Tb + Q/(G-C-r) - (2)
is required.

If the filter (7>) is clogged, the intake air will naturally decrease and the air volume to the heaters (18) (19>) will be smaller than the G, so from equation (2) above,
If clogging occurs, the temperature Tc will be the reference temperature (Tc).
be higher than Therefore, Tc and T(T
c), if Tc is less than T(Tc), it is normal, and if Tc is greater than or equal to T(Tc), it is determined that clogging has occurred, and a clogging flag is set ( S-13
).

Now, in Figure 2, the clogging notification program (S-1
4> is always executed while the power switch is turned on.

That is, when the clogging flag is set in (S-13), the microcomputer (54) immediately turns on the clogging display LED.
(49) is made to blink (S-15).

Then, during this clogging display, when the lid (6) is opened and the lid switch (34) open signal is input), the buzzer sounds for 5 seconds (S-16>, therefore, Even if the user does not notice the flashing of the LED (49), the user can notice it due to the buzzer sound, and can remove the clogging of the filter (7) as appropriate.

In addition, the microcomputer (54) determines whether the opening operation of the lid (6) is in drying operation (heater ON) in (S-17>), and if drying operation is in progress, a clogging flag is flagged. 5-18>, and if it is after cool-down operation, use the various setting keys (36) (37) (3) after that.
8) Prohibits acceptance of input.

That is, during drying operation, the material to be dried is in a half-dried state,
Regardless of whether the filter (7) is clogged, it is necessary to finish drying. Even if the filter (7) is not completely clogged when the lid (6) is opened, the clogging can be detected and displayed again using the clogging detection program.

On the other hand, after the cool-down operation, the drying has already finished, and there is a concern that the second drying operation will be performed with the filter (7) still clogged, so by prohibiting the reception of key human power, This prevents a second drying operation and at the same time requires the user to install the filter (7).
This clogging notification program, which urges removal of clogging, can be canceled by turning off the power once.

Next, the detection of a failure (disconnection, short circuit, etc.) in the third temperature detection circuit (59) will be explained.
The microcontroller (
54), a temperature of -30°C, which is normally unthinkable, is detected, so this causes the microcomputer (
54) are the first and second temperature detection circuits (57) (5
8) can determine the failure.

However, since the third temperature detection circuit (59) detects the temperature at the outlet of the heater, it is characterized so that it can detect temperatures in the range of 100°C to 200°C, and if this fails, the microcomputer (54) In this case, a temperature of approximately 80°C was detected, and it is difficult to determine whether or not there is a malfunction.

Therefore, the ROM (73) has a predetermined temperature (120
℃), and if the temperature Tc does not exceed the specified temperature during the drying operation, it is determined that there is a failure.

This malfunction display is not performed during drying operation.
When the cool-down operation begins, the standard course L
ED (42) flashes and the buzzer goes off for 0.5 seconds.
The sound is emitted intermittently for a predetermined period of time with a cycle of OFF for N-0.5 seconds. Note that this failure detection is not performed before the constant drying period.

(G) Effects of the Invention The dryer of the present invention can appropriately correct variations in mti temperature and heater characteristics, and can always accurately detect filter clogging.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing the operation of the clogging detection program in the dryer of the present invention, FIG. 2 is a flowchart showing the operation of the clogging notification program, and FIG. 3 is a flowchart 1. , Fig. 4 is a side sectional view of the dryer, Fig. 5 is a front view of the operating section, Fig. 6 is an electric circuit diagram, Fig. 7 is a configuration diagram of the microcomputer, Fig. 8 is a drying characteristic diagram, 9 and 10 are output characteristic diagrams of the PTC heater with respect to temperature and air volume. (1)...M frame, (2)...Drum, (7)...
Filter (18) (19)...Positive temperature characteristic heater,
(54)...Microcomputer (control means),
(58)...second temperature detection circuit (temperature detection circuit B),
(59)...Third temperature detection circuit (temperature detection circuit C),
(65) Current transformer (current detection means).

Claims (1)

[Claims] (1) A drum for storing materials to be dried is rotatably supported within the machine frame, and the exhaust air from the drum is filtered to remove dust, heat exchanged to remove moisture, and then recycled by a positive temperature characteristic heater. In the dryer which is heated and supplied to the drum, temperature detection means B detects the temperature Tb of the dry air before being heated by the heater, and the temperature Tc of the dry air after being heated by the heater. temperature detection means C for detecting; current detection means for detecting the value of the current flowing through the heater;
From the heater current value detected based on the signal from the current detection means, calculate the amount of heat Q of the heater, and from the value of either the temperature Tb or the temperature Tc, calculate the other reference temperature according to the following formula, Q=G・C・r(Tc−Tb) Where, G: Specified air volume, C: Specific heat of air, r: Specific gravity of air. Comparison result between the above reference temperature and the other value of the above temperature Tb or temperature Tc. A dryer comprising: control means for determining clogging of the filter based on the above.