JPH01119298A - Clothes-dryer of drum type - Google Patents

Abstract

PURPOSE: To satisfactorily tumble objects to be dried and to eliminate non-uniformity in drying by arranging a control system for variably controlling the number of rotations per unit time of a drum corresponding to the detecting signals of temperature near an air inflow to the drum and temperature or humidity near an air outflow. CONSTITUTION: After the start of operation, while keeping the number of rotations per unit time of the drum of f1 , a drum exit temperature To and a heater entrance temperature Ti detected by sensor parts 17 and 18 are transited with a fixed temperature difference for a while. After time t0 , a temperature difference (To -Ti ) starts increasing and at time t1 , the temperature difference (To -Ti ) gets equal with ΔT1 preset by a control circuit 19. Then, a frequency down command is outputted from the control circuit 19 to an inverter circuit and operation is performed while keeping the number of rotations per unit time of the drum of f2 just for certain fixed time Δt. In this case, the tumbling of objects to be dried in the drum is made satisfactory. Such operation is repeated several times, the objects to be dried are dried without non-uniformity, the temperature is elevated without lowering the exit temperature To and at the time when the temperature difference (To -Ti ) becomes ΔTs (at time t4 ), drying is finished.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a clothes dryer for home or commercial use.

<Prior Art> The structure of a conventional drum-type clothes dryer is shown in FIG. A drum 1 containing items to be dried such as clothes is supported by a bearing 2 and can rotate around a horizontal axis.

Pulley 4 and pulley 4 using motor 8 as a driving source
and the drum 1 by the drum belt 5 suspended on the drum l.
is driven at a constant rotation speed. An air inlet 6 and an air outlet lower are provided on both sides of the drum 1, and a heater 8 is provided.
The heated air flows into the drum 1 from the air inlet 6, evaporates moisture from the material to be dried 9, and flows out from the air outflow lower. In some cases, the air flowing out from the air outflow lower is directly exhausted to the outside of the machine (exhaust type clothes dryer), and in other cases, moisture contained in the air is removed by a dehumidifier and the dry air is sent to the heater 8 for air circulation. There is a dehumidifying type clothes dryer), but here we have shown a diagram for the dehumidifying type.

The humid air coming out of the air outlet exchanges heat with the outside air on the surface of a double-winged fan 140 that serves as both a fan and a heat exchanger to condense moisture, and the condensed moisture is discharged to the outside of the machine from the drain port 15. The air from which moisture has been removed is conveyed to the vicinity of the drum 1 through the circulation duct 10 and heated by the heater 8. The double-wing fan 14 is a Boo! that is integrated with the pulley 11 attached to the shaft of the motor 3, the fan belt 13, and the double-wing fan. It is driven by J-12 and performs flow of circulation side air and outside air and heat exchange between them.

The material to be dried 9 is lifted upward along the cylindrical wall within the drum 1 as the drum 1 rotates, and falls due to gravity.

During this time, moisture is evaporated while coming into contact with hot air, and the entire object 9 to be dried can be dried evenly by the above-described action of replacing the object to be dried (tampling).

The completion of drying is determined by the drum outlet air temperature T determined by the temperature sensor 17.
It is detected by the heater artificial air temperature T+ by the temperature sensor 18. As shown in FIG. 4, To and Ti change over time, with To increasing and Ti decreasing slightly toward the end of drying. Therefore, when the difference To - Ti reaches a certain set value, it is assumed that drying has ended and the operation is stopped.

<Problems to be Solved by the Invention> According to the above-described conventional structure, the drum rotation speed is constant regardless of the amount or nature of the material to be dried. In this case, if the amount of material to be dried increases, or if materials with low specific gravity and large area per sheet (such as sheets) enter, tampling inside the drum will deteriorate, resulting in uneven drying. It becomes impossible to obtain dryness. If the tampling is poor as described above, the air inside the drum will only come into contact with the material to be dried in a certain location, which will cause uneven drying. At this time,
As shown by the solid line in Figure 3, To and Ti start changing earlier than when tampling is good (dashed line), and when the difference in TO and TiO reaches the set value, it is determined that drying is complete and the operation is started. stop. - In this case, a part of the material to be dried showed good dryness, but other parts were not sufficiently dried, and the drying was uneven as a whole.

Means for solving the above problems> As a means for solving the above problems, when detecting the drum outlet air temperature To or humidity, detecting whether the drum outlet air humidity has started to change significantly or the drum outlet air temperature To It is detected that the drum reaches a certain value smaller than the set value Δ'r s for determining the end of drying, and from that point on, the drum rotates at a low speed until the end of drying is detected. Add a control function to temporarily reduce (or stop) the drum rotation speed at that point.

<Function> When the amount of material to be dried is small, if the drum is rotated at a speed that does not allow the material to be dried to remain stuck to the inner wall of the drum due to centrifugal force, the tampling condition will be good and the drying performance will be good. It is. However, when operating at the same rotation speed as above, if the amount of material to be dried increases, or if objects with low specific gravity and large area per sheet are introduced, it becomes difficult to move the material to be dried within the drum. . Therefore, in this case, by lowering the rotational speed of the drum, the centrifugal force exerted on the material to be dried can be weakened, and when the material to be dried moves to the upper part of the drum, it can be made easier to fall due to gravity.

<Embodiment> FIG. 1 is a schematic configuration diagram of a clothes dryer used to explain one embodiment of the present invention. Components that are the same as in FIG. 4 are designated by the same numbers. A motor 3' is installed to drive the double-wing fan 14. By means of this motor 8', both wings 7 and 14 are operated at the same constant rotational speed as that in FIG.

The drum drive motor 3'' is connected to an inverter circuit 16, and the rotation speed is variable.A drum outlet air temperature sensor 17 and a heater artificial air temperature sensor 18 are connected to a control circuit 19, which controls the inverter. Controls the frequency generated in circuit 16. Drum exit air temperature T.

The control circuit 19 is programmed to issue a command to the inverter circuit 16 to temporarily reduce the frequency when the temperature difference between the temperature and the heater artificial air temperature Ti reaches ΔTl (ΔT1 × ΔTs). Here, one example of changes in temperature and frequency (-!Drum rotation speed) according to the present invention is shown in FIG. 2.

After the start of operation, the drum rotational speed remains fl, and the drum outlet temperature To and the heater population temperature Ti remain at a substantially constant temperature difference for a while. and from time to to To −T
i starts to increase and at time t1 'r o −
T i becomes equal to ΔTl set in advance by the control circuit. Therefore, a command is issued from the control circuit to the inverter circuit to reduce the frequency, and the drum rotation speed is f for a certain period of time Δt.
It is driven by 2.

Here, the material to be dried in the drum has good tampling, is replaced within the drum, and the portions that are not in a good drying state are newly exposed to high-temperature air, and the drum outlet temperature To decreases again due to the latent heat of evaporation. The drum rotational speed is again operated at fl, and when To-Ti increases and reaches ΔTl (time 12), the same action as the previous one is repeated. Then, at time t8, To −T i =Δ′rlVc
The rotation speed reached f2, but since the material to be dried was dried evenly, To did not decrease and the temperature continued to rise, and when To-Ti = ΔTs (time t4), drying was started. finish. In this example, the drum rotation speed changed from fl to 12 three times, but this number changes depending on the amount and nature of the material to be dried. The broken line in FIG. 2 is an example of the temperature change in To when the control according to the present embodiment is not performed in a bad tampling condition, and the temporal change in (To-Ti) is gradual, and the operation stops at time t4. However, the actual material to be dried is unevenly dried, and only a portion of the material is dried.

FIG. 3 is an explanatory diagram showing changes in temperature and drum rotation speed in a second embodiment of the present invention. This is time t1
When 'ro-Ti becomes ΔT1, the drum rotation speed decreases from fl to f2, and at this time, ro-Ti becomes smaller as in the fourth embodiment. After that, the drum rotation speed is f2
Leave it as it is and end the operation when To-Ti=ΔTs.

In addition, 1. In the second embodiment, the drum rotation speed may be controlled by measuring the humidity at the drum outlet and detecting this change.

<Effects of the Invention> According to the present invention, the tampling of the material to be dried in the drum is better than before, regardless of the amount or nature of the material to be dried, and in particular, uneven drying due to poor tampling of the material to be dried can be efficiently eliminated. Ru.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a drum-type clothes dryer for explaining one embodiment of the present invention. FIG. 2 is a time chart diagram of control elements showing one embodiment of the present invention. FIG. 8 is a time chart diagram of control elements showing another embodiment of the present invention. FIG. 4 is a structural diagram of a conventional drum type clothes dryer. FIG. 5 is a characteristic diagram showing changes in drum outlet temperature and heater inlet temperature of the clothes dryer shown in FIG. 4. FIG. FIG. 6 is a characteristic diagram showing changes in drum outlet temperature and heater inlet temperature based on the quality of the tampling. 1...Drum 2...Bearing 3'...Double-blade fan drive motor 3"...Drum drive 7-amp 4...
・Drum pulley 5...Drum belt 6...Air inlet 7...Air outlet 8...Heater 9
... Item to be dried 1゜ ... Circulation duct 11 ... Drive side fan pulley 12 ... Fan side 77 inches 7"-
IJ-13...7 Umberto 14...Double wing fan
15... Drain port 16... In 18... Heater artificial air temperature sensor 19... Control circuit agent Patent attorney Takeshi Sugiyama (and 1 other person) Fig. 2 eo t+ 74 No. 30 Inka

Claims (1)

[Claims] 1. In a drum-type clothes dryer that supplies hot air to a rotating drum that accommodates items to be dried to remove moisture contained in the items to be dried, and then exhausts humid air in the drum, the drum a sensor unit that detects the temperature near the air inlet to the drum and the temperature or humidity near the air outlet from the drum; and a control system that variably controls the rotation speed of the drum in accordance with a detection signal from the sensor unit. A drum-type clothes dryer characterized by adding the following.