JP3446292B2 - Clothes dryer - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clothes dryer for circulating warm air into a rotating drum driven by a motor to dry clothes. [0002] In recent years, household clothes dryers are provided with a filter for removing lint and the like in a rotating drum for drying the clothes. A clothes dryer that reports clogging by an indicator light has been proposed. Conventionally, this type of clothes dryer has been disclosed in
No. 16631. That is, a current change of a positive characteristic temperature-sensitive resistance heater (hereinafter, referred to as a PTC heater) is detected by a current transformer, and if the detected PTC heater current is smaller than a set value, clogging is notified. [0004] In such a conventional clothes dryer, the PTC heater current changes depending on the intake air temperature, air volume, and voltage. Since the current change of the PTC heater due to the amount is much larger than the current change due to clogging, it is almost impossible to find a set value that can detect clogging only by the current change in consideration of all fluctuations. Has a problem that it is impossible to detect a clogged state. [0005] The present invention solves the above-mentioned conventional problems.
An object of the present invention is to be able to detect clogging of a filter without being affected by a change in temperature, a change in voltage, or a change in air volume. [0006] In order to achieve the above object, the present invention provides a rotating drum for drying clothes, a blowing means for circulating warm air into the rotating drum, and a rotating drum. A heating means comprising a PTC heater provided in the air supply path, a filter provided in the air supply path, a motor for driving the air supply means or the rotary drum, and a rotation number or rotation cycle of the rotary drum, the motor or the like. Rotation detecting means for detecting, a control means for controlling the number of rotations of the motor and the heating means, a temperature detecting means provided in a ventilation path to the heating means, and a current of the heating means connected to the control means. Current detecting means for detecting, and notification means, the control means, when the rotation of the motor is started,
In a state where the number of rotations of the motor is controlled to a substantially minimum controllable number of rotations for a certain period of time, the clogging of the filter is detected by the output signal of the temperature detection means and the output signal of the current detection means , Increased to operating speed
And the drying operation is performed, and the filter is clogged.
When it is determined that clogging has occurred, the clogging of the filter is reported by the reporting device after the drying operation is completed. According to the present invention, a PTC is provided by the above-mentioned means for solving the problems.
Detects clogging of the filter based on the intake air temperature of the heater and the electric power applied to the PTC heater, accurately detects clogging regardless of voltage change or temperature change, starts up with the PTC heater current reduced, and starts the PTC heater. There is no interruption of the power supply breaker due to the inrush current of the motor, and operation is performed at a controllable minimum rotation speed for a certain period of time. In addition, since the notification is made after the driving is completed, it is possible to prevent the user from becoming nervous or suspicious, or to stop the driving and perform cleaning, for example, as compared to the case where the display is made during driving. An embodiment of the present invention will be described below with reference to FIGS. 1 and 2. As shown in the figure, a rotary drum 1 is for storing and drying an object to be dried (clothing), and circulates warm air in the rotary drum 1 by a heat exchange type double-wing fan (blower means) 2. The heat exchange type double-wing fan 2 circulates warm air in the rotating drum 1 and simultaneously takes in air from the outside to cool the fan and dehumidifies the circulating air in the rotating drum 1. P
The TC heater (heating means) 3 is disposed in a blowing path to the rotary drum 1, that is, in a circulating air intake, and heats circulating air. The filter 4 is provided in a blowing path of the heat exchange type double wing fan 2, that is, an air outlet of the air in the rotating drum 1. If the filter 4 is clogged by lint or the like, the amount of air to be blown is reduced, the heating power of the PTC heater 3 is reduced, and the drying time is prolonged and the drying efficiency is reduced. Motor 5
Is for driving the rotary drum 1 and the heat exchange type two-blade fan 2 to rotate. By controlling the rotation speed of the motor 5, the rotation speed of the rotary drum 1 and the heat exchange type two-blade fan 2 can be controlled. The amount of heat generated can be controlled, and current control can be performed. The temperature detecting means 6 detects the temperature of the intake air of the PTC heater 3. The rotation detecting means 7 detects the number of rotations of the rotating drum 1, and two to six magnets 8 are attached to the rotating drum 1, and a magnetic sensor (not shown) is fixed to the main body to rotate the rotating drum 1. 1 is detected. The control means 9 is a motor 5
A rotation speed setting means 10 for controlling the rotation speed of the rotary drum 1 and a rotation speed comparison means for comparing the output of the rotation detection means 7 and the output of the rotation speed setting device 10 with each other. 11, a conduction angle control means 13 for controlling a conduction angle of a bidirectional thyristor 12 connected in series to the motor 5 by an output of the rotation speed comparison means 11, and a low-speed start means for lowering a set rotation speed when the motor 5 is started. 14, a temperature control means 15 for inputting the output of the temperature detecting means 6, a clogging detection level setting means 16, and a clogging notification judgment for comparing the output of the clogging detection level setting means 16 with the output of the current detecting means 17. And means 18. The difference between the rotation speed of the rotary drum 1 detected by the rotation detection means 7 and the rotation speed set by the rotation speed setting means 10 is compared by the rotation speed comparison means 11, and the conduction angle control means 13 controls the bidirectional thyristor. 12 to control the motor 5
To control the number of revolutions. Phase control is considered as the simplest conduction time control method. In the case of an inverter, not only the conduction time but also the frequency is controlled. In this way, stable rotation control of the motor 5 and the rotating drum 1 can be performed. The output of the temperature detecting means 6 for detecting the temperature of the circulating air of the rotary drum 1 is input to the temperature control means 15, and the PTC heater 3
relay contacts 19a, 19b respectively connected to a, 3b
And the PTC heaters 3a and 3b are turned on and off to control the temperature of the circulating air. Further, the temperature detecting means 6
The output of the clogging detection level setting means 16 and the output of the current detecting means 17 to which the output of the filter 4 is input are input to the notification determination means 18, and the notification means 20 notifies the clogging of the filter 4. The operation setting means 21 is connected to the control means 9 to set and operate a plurality of types of operation courses. The operation setting means 21 is inputted to the rotation number setting means 10 to change the rotation number of the rotary drum 1 according to the operation course. To be set to
The temperature inside the rotary drum 1 is controlled according to the operation course according to the output of the temperature control means 15 and input to the temperature control means 15. The current detecting means 17 includes a current transformer 2
2 and a current-voltage conversion circuit 23, which detects the input current of the PTC heater 3 and outputs the output to the current comparison setting means 2.
Enter 4 The current comparison setting unit 24 compares the set current value of the PTC heater 3 with the output of the current detection unit 17,
The output is input to the rotation speed setting means 10 to control the set rotation speed. Here, the set rotation speed set by the rotation speed setting means 10 is set such that the current of the PTC heater 3 does not become equal to or more than a predetermined current value. The output of the current detecting means 17 is input to the clogging notification determining means 18 together with the output of the clogging detection level setting means 16 for calculating the clogging detection level based on the output of the temperature detecting means 6. The output of the clogging detection level setting means 17 and the output of the current detecting means 17 are compared with each other in a state where the number of rotations is set to the lowest controllable number of rotations, and the notifying means 20 notifies the filter 4 of clogging. I have to. That is, by controlling the rotation of the heat exchange type double-blade fan 2, the blowing condition at the time of detecting the clogging is set to be constant. The operation of the above configuration will be described with reference to FIGS. 3 to 7. First, FIG. 3 shows the characteristics of the input power P of the PTC heater 3 and the intake air temperature T for illustrating the method of detecting clogging according to the present invention. FIG. 3 is a diagram showing an input power P of the PTC heater 3 as a temperature difference T
P = H (Tq-T). When the filter 4 is clogged, the radiation coefficient H decreases due to a decrease in air flow due to the clogging, so that the Curie temperature Tq
Is constant, the heat radiation coefficient H can be obtained from the input power P and the intake air temperature T, and clogging can be estimated. The characteristic A in FIG. 3 shows the relationship between the input current I of the PTC heater 3 and the intake air temperature T when the amount of clothing is small, the characteristic A 'when the amount of clothing is large, and the characteristic B when the filter is clogged. It shows the characteristic of. Is is a PTC heater 3 for the intake air temperature T for determining clogging.
Of the input current I of FIG. The detection level Is can be set substantially linearly in accordance with the intake air temperature T, such as Is = K−kT. Here, K and k are constants. Next, the detection of clogging is performed by controlling the number of rotations of the rotary drum 1, in other words, the number of rotations of the motor 5 to a constant value. That is, as shown in FIG. 4, at time t0, the low-speed starting means 14 changes the rotation speed set by the rotation speed setting means 10 to the low rotation speed n1 (the rotation speed 4 of the rotating drum 1 during normal operation).
For example, 36 rpm is set for 5 rpm, and the process is started. Then, at time t1 at which a predetermined time (for example, 3 minutes) has elapsed, the set number of revolutions is calculated by the number of revolutions setting means 10 according to the temperature detected by the temperature detecting means 6,
Based on the set rotation speed, the rotation speed of the motor 5 is controlled, and the rotation speed is gradually increased. The finally set upper limit rotation speed n2 is reached, and after time t2, the rotation speed becomes substantially constant. The clogging detection is performed one to two minutes before time t1. FIG. 5 shows the air volume and heater current characteristics of the PTC heater 3, and the power supply voltage is constant. In the initial stage of operation, the number of revolutions of the heat exchange type two-blade fan 2 is reduced to reduce the amount of air circulating through the PTC heater 3, so that the air volume Q1 and the heater current I1 are reduced.
Can be smaller than the air volume Q2 and the heater current I2 when the fan rotation speed is high, and the inrush current can be reduced. Also, the current change rate (I1-Q1 ') with respect to the air flow rate change rate (Q1-Q1') when the filter is clogged.
I1 ′) is the current change rate (I2) with respect to the air flow rate change rate (Q2−Q2 ′) when the rotation speed of the heat exchange type two-wing fan 2 is high.
2-I2 ′). Therefore, by lowering the rotation speed of the heat exchange type double-blade fan 2 at the time of clogging detection, the current change rate due to filter-clogging can be increased, and clogging detection accuracy can be improved. Next, the operation will be described in detail with reference to FIG. 6. The operation is started in step 30, the operation is initialized by the operation setting means 21 in step 31, and the soft start is performed in step 32. That is, the low-speed starting means 14 sets the rotation speed set by the rotation speed setting means 10 to the low-speed rotation speed n1, and starts. Then, in step 33, clogging detection is performed by setting the set number of revolutions to the lowest controllable number of revolutions (may be lower than n1). Next, at step 34, the current detecting means 17
, The current of the PTC heater 3 is detected, and the detected current is input to the rotation speed setting means 10 via the current comparison and setting means 24, and the set rotation speed is calculated in step 35. 5 and control proceeds to step 39 via steps 37 and 38, and to step 33
When the clogging notification flag is turned on, clogging notification is performed. The clogging detection operation will be described with reference to FIG. 7. In step 50, a clogging detection subroutine is started, and in step 51, the rotational speed of the rotary drum 1 is controlled to be substantially constant at the minimum rotational speed n1. After a delay of a predetermined time (for example, 3 minutes) in step 52, the temperature of the circulating air is detected by the temperature detecting means 6 in step 53. Next, at step 54, the clogging detection level setting means 15
To calculate the detection level Is shown in FIG. Thereafter, at step 55, the current detecting means 17
, The current I of the PTC heater 3 is detected.
Then, the detection level Is is compared with the current I. When the filter 4 is clogged, the amount of circulating air decreases,
If I <Is, in step 57, the clogging notification flag is turned on, and after the operation is completed, an output is issued from the clogging notification determining means 18 and the notifying means 20 enables clogging notification. Then, in step 58, the clogging detection flag is turned on, the process proceeds to step 59, and returns to step 33 in FIG. As described above, according to this embodiment, after the rotation speed of the rotary drum 1 is set to the lowest rotation speed at the start of operation, the controllable almost lowest rotation speed is set before the normal rotation speed is increased. After a certain period of time, the clogging of the filter 4 is detected based on the output signal of the temperature detecting means 6 and the output signal of the current detecting means 17, so that the filter is not affected by temperature change or voltage change. Can be detected, and the detection accuracy can be improved. As described above, according to the present invention, a rotating drum for drying clothes, a blowing means for circulating warm air into the rotating drum, and a blowing path to the rotating drum are provided. Heating means comprising a PTC heater, a filter provided in the air blowing path, a motor for rotating the air blowing means or the rotating drum, and a rotation detecting means for detecting the number of rotations or the rotation period of the rotating drum, the motor and the like. When,
Control means for controlling the number of rotations of the motor and the heating means, a temperature detection means provided in a ventilation path to the heating means, a current detection means connected to the control means and detecting a current of the heating means, Notifying means, the control means, when the rotation of the motor is started, in a state where the rotation speed of the motor is controlled to a substantially minimum controllable rotation speed for a certain period of time,
Clogging of the filter is detected by the output signal of the output signal of the current sensing means of said temperature sensing means, that
After that, increase the number of rotations during normal operation and perform drying operation
At the same time, the filter is clogging
If it is determined, the clogging of the filter is notified by the notification means after the drying operation is completed. Can be detected accurately regardless of voltage or temperature changes, and can be started with the PTC heater current lowered,
There is no interruption of the power supply breaker due to the inrush current of the heater, and the clogging of the filter can be detected at the beginning of the operation, so that the accuracy of detecting the clogging can be improved. It can prevent misuse such as cleaning.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram of a clothes dryer according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the clothes dryer. FIG. FIG. 4 is a diagram showing a relationship with current. FIG. 4 is a diagram showing a change in the number of rotations when detecting filter clogging of the clothes dryer. FIG. 5 is a graph showing the relationship between the air flow of a PTC heater and the heater current of the clothes dryer. Diagram showing the relationship [FIG. 6] Operation flowchart of the clothes dryer [FIG. 7] Flow chart of filter clogging detection of the clothes dryer [Description of symbols] 1 rotating drum 2 heat exchange type double-wing fan (blowing means) 3 PTC Heater (heating means) 4 filter 5 motor 6 temperature detection means 7 rotation detection means 9 control means 17 current detection means 20 reporting means

────────────────────────────────────────────────── ─── Continuation of the front page (72) Akira Shoji, Inventor 1006 Kazuma Kadoma, Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-6-15100 (JP, A) JP-A-5- 115695 (JP, A) JP-A-4-126199 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) D06F 58/28

Claims (1)

(57) [Claim 1] A rotating drum for drying clothes, a blowing means for circulating warm air into the rotating drum, and a PTC heater provided on a blowing path to the rotating drum. Heating means, a filter provided in the blowing path, a motor for rotating the blowing means or the rotating drum, a rotation detecting means for detecting the number of rotations or a rotation cycle of the rotating drum, the motor, etc., and the motor Control means for controlling the number of revolutions of the heating means and the heating means, temperature detection means provided in a ventilation path to the heating means, current detection means connected to the control means for detecting a current of the heating means, and notification means Wherein the control means is configured to start rotation of the motor.
In a state in which a certain period controlled substantially minimum rotational speed that can control the rotational speed of the motor, detecting the clogging of the filter by the output signal of the output signal of the current sensing means of said temperature detecting means, then , Up to normal operation speed
As well as drying operation, and the filter
If it is determined that clogging is occurring, the clogging of the filter is performed by the notification unit after the drying operation is completed.
Clothes dryer that alerts you.