JPH0559759B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a clothes dryer for use in general households and the like.

Conventional structure and its problems Conventionally, clothes dryers have installed electrodes in the drum to detect the wetness of clothes electrically, and use electronic control circuits to measure the degree of change in wetness or dryness. The user can select the degree of dryness, such as "complete dryness", by operating a switch. However, with this method, it is possible to detect a "wet-dry" state (a damp-dry state that can be used with ironing, etc.), but
When the clothes begin to dry, only the surface of the clothes is dry, but the inside of the clothes is not yet dry, which may be mistakenly detected as "completely dry." Therefore, it is necessary to include a correction circuit in the control circuit or a circuit for delaying a certain period of time, which has the disadvantage of being complicated and expensive. Also, in terms of accuracy, there is a lot of variation in the timing of "complete drying", and "overdrying"
There were many things that happened.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned conventional drawbacks, and aims to improve the accuracy during complete drying, and to provide a method at low cost that does not require a delay circuit or a correction circuit.

Structure of the Invention In order to achieve the above object, the clothes dryer of the present invention is a rotating drum type clothes dryer that rotates a drum to agitate the clothes and also blows hot air into the drum to dry the clothes. Temperature sensing elements are provided near the drum front plate and near the rear exhaust part of the drum, which are located nearby. The nearby temperature detection element is configured to detect an almost completely dry state,
A switch is provided to arbitrarily select between "wet and dry" and "completely dry";
When set, the drying end point is determined based on the temperature rise change of the temperature detection element near the front plate of the drum, and when "Complete Dry" is set with the changeover switch, the temperature of the temperature detection element near the rear exhaust of the drum is determined. The point at which drying ends is determined based on the upward change.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

In Figure 1, 1 is the body of the clothes dryer, 2
is a rotating drum, and this rotating drum 2 is driven by a motor 3 via a belt 4 and a pulley 5. A double-blade fan 6 also serves as a heat exchanger, and is driven by the motor 3 via a belt 7 and pulleys 8 and 9. 10 is a sliding felt that serves as a bearing for the rotating drum 2, and 11 is a filter that traps dust on clothing. Reference numeral 12 denotes a door, which is opened and closed to throw clothes into the rotating drum 2. 13 is a heater, rotating drum 2
heats the air flowing into it. 14 is a temperature sensing element such as a thermistor provided near the front plate of the rotating drum 2, and 15 is a temperature sensing element such as a thermistor provided near the rear exhaust part of the rotating drum 2. 16 is a control panel provided on the upper end of the front plate of the body 1, and as shown in FIG.
Push-button type dryness changeover switches 18 and 19 are provided, and when the changeover switch 18 is pressed, the operation becomes "wet dry", and when the changeover switch 19 is pressed, the operation becomes "complete dry".

Next, the operation will be explained. Power supply 100V, heater 1200W, circulating air volume on the hot air side in the direction of arrow a in Figure 1, approximately 2 m ² /min, cooling air volume in the direction of arrow b in Figure 1, approximately 3 m ² /min.
In a household electric clothes dryer with a drying capacity of 2 kg (dry cloth), you can wash ordinary cotton underwear.
When drying is carried out after dehydration, the relationship between the drying time and the temperature at the mounting points of the temperature sensing elements 14 and 15 is shown in FIG. T ₁₄ indicates a temperature curve of the 14th part of the temperature sensing element near the front plate of the rotating drum, and T ₁₅ shows a temperature curve of the 15th part of the temperature sensing element near the exhaust part on the rear side of the rotating drum. At T ₁₄ , the temperature rise point P is early (about 60 minutes), and at T ₁₅ , the temperature rise point Q is slow (about 80 minutes). This phenomenon occurs because the temperature of the temperature sensing element 14 on the front plate of the rotating drum starts to rise when the surface of the clothing begins to dry, so the rising point is early, and the temperature sensing element 15 on the rear side of the rotating drum prevents water from evaporating from the clothing. This is because the temperature starts to rise (as drying progresses to the inside of the clothing and the evaporated water disappears), which causes the rise point to be delayed. Utilizing this phenomenon, it is convenient to use the temperature detection element 14 to detect "wetness/dryness" and the temperature detection element 15 to detect "complete dryness." In other words, since both wet dryness and complete dryness can be detected at the point where the temperature change becomes large, the accuracy of dryness detection for wet dryness and complete dryness can be improved. In reality, it did not become "completely dry" at point Q, and the temperature rose a little more.
It has been experimentally confirmed that "complete dryness" occurs at point Q', so the temperature gradient (time: t, temperature: T
ΔT/Δt (as T ₂ and T ₁ in the figure), and the appropriate temperature rise value T ₂ − T ₁ that increases from the steady temperature T ₁ to T ₂ is experimentally determined and the detection operation is performed (control (Circuit not shown).

The operation is very simple: turn on the power switch 17 shown in Fig. 3, press the changeover switch 18 if the desired degree of dryness of the clothes to be dried is "wet dry", or press the changeover switch 19 if the desired degree of dryness of the clothes to be dried is "complete dry". Just press . After that, it detects when a predetermined degree of dryness is reached and automatically stops the drying operation.

Although the test data for ordinary cotton clothing was described above, substantially the same phenomenon occurs even when the type and amount of clothing is changed, so there is no need to particularly consider the control circuit. If "overdrying" is necessary, for example, as shown in FIG. 3, a changeover switch 20 can be provided on the control panel 16 to stop the process when the temperature increase value T ₂ -T ₁ further increases. good.

Although the above embodiment shows a double-wing fan type dehumidifying clothes dryer that also serves as a heat exchanger, it can also be applied to a normal exhaust fan type clothes dryer.
Further, instead of a mechanism for automatically ending drying, a means for notifying the end of drying may be provided so that the user turns off the switch.

Effects of the Invention As described above, according to the present invention, it is possible to provide an inexpensive clothes dryer that is extremely easy to operate, can improve dryness detection accuracy, and does not require a delay circuit or a correction circuit.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which FIG. 1 is a longitudinal sectional view, FIG. 2 is a temperature curve diagram, and FIG. 3 is a front view of a control panel portion. 1...Body, 2...Rotating drum, 3...Motor, 6...Double wing fan, 11...Filter, 1
3... Heater, 14, 15... Temperature sensing element, 1
6... Control panel, 17... Power switch, 18-20... Changeover switch.

Claims (1)

[Claims] 1. In a rotating drum type clothes dryer that rotates the drum to agitate the clothes and send hot air into the drum to dry the clothes, there is a Each drum is provided with a temperature sensing element, and the temperature sensing element near the front plate of the drum detects a wet and dry state in the relatively early stage of dryness, and the temperature sensing element near the rear exhaust part of the drum detects an almost completely dry state;
A switch is provided to arbitrarily select between "wet and dry" and "completely dry";
When set, the drying end point is determined based on the temperature rise change of the temperature detection element near the front plate of the drum, and when "Complete Dry" is set with the changeover switch, the temperature of the temperature detection element near the rear exhaust of the drum is determined. A clothes dryer that determines the end point of drying based on the change in elevation.