JPH04253897A - Drum-type dryer - Google Patents

Abstract

PURPOSE:To prevent materials to be washed from being rolled or getting entangled by allowing operation at the optimum rotational speed of a drum continually with a temp. detector which detects an exhaust air temp. from the drum, and a driving means which varies rotational speeds of the drum. CONSTITUTION:When a drying operation is started, a motor 15, a blowing fan 12, a cooling fan 5 and a heater 3 are energized, and an air sucked into a blast duct 8 through a suction opening 25 of a tub 13 is dehumidified by a heat exchanger 4, thereafter heated by the heater 3 to be a hot dry air, and is blown into the tub 13 through a nozzle 24. The dry air blown into a drum 2 evaporates moisture of the materials to be washed and becomes an air of low temp. and high humidity. The materials to be washed in the drum 2 is lifted close to the highest part of the drum 2 with a baffle 20 when the drum rotates on its own axis at a rotational speed NO, then disentangled while falling by its self-weight, and exposed to a hot dry air evenly.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drum dryer, and more particularly to a drum dryer with excellent drying efficiency.

0002

[Prior Art] Such a conventional drum dryer has a structure in which a drum rotates around a horizontal axis within a water tank, and the laundry stored in this drum is washed and dried in the same way. A typical product is the washer/dryer, which has washing, dehydrating, and drying functions because it uses a drum. Such a drum-type washer/dryer can also be used as a fully automatic laundry machine that does not require any human intervention until the laundry is completely dried after the laundry is loaded into the drum. Further, in a conventional drum-type washer/dryer, the drum rotation speed during the drying process is always constant. However, the optimal rotational speed of the drum is not necessarily the same at the initial stage of drying, when the cloth absorbs a large amount of water, at constant rate drying, and at decreasing rate drying (late drying period) when the bulk of the cloth increases. Therefore, in the conventional drum dryer, good tumbling cannot always be obtained, and cloth tangles occur, making it impossible to shorten the time sufficiently or achieve a high level of drying efficiency. The above-mentioned contents are particularly noticeable when drying at a low bath ratio (drying at a low bath ratio, that is, drum volume (liter)/dry clothes weight (Kg)).

0003

In the prior art, the number of rotations of the drum during the drying process is always constant, which causes the following problems. 1. If the drum rotation speed is set to the optimum rotation speed in the early stage of drying, the rotation speed is too high and good tumbling cannot be achieved after the middle stage of drying when the bulk of the fabric increases. 2. On the other hand, if the rotation speed is set lower than the optimum rotation speed after the middle stage of drying, that is, the above-mentioned setting value, the cloth will not be lifted up in the early stage of drying and will form a roll, resulting in extremely poor drying conditions. 3. In the latter stage of drying, when the bulk of the fabric increases and the movement of the fabric decreases, resulting in worsening of tumbling, it becomes difficult for drying air to pass through the center of the fabric.

0004

[Means for Solving the Problems] The drum dryer of the present invention is configured to circulate dehumidified warm air through a rotating drum, and detects the temperature of exhaust gas from the drum. a temperature sensor that changes the rotational speed of the drum, a drive means that changes the rotational speed of the drum, and a drum rotational speed N0.
After starting operation, when the drum exhaust temperature rises and reaches T1, the drum rotation speed is reduced to N1 (<N0), and when the drum exhaust temperature rises further and reaches T2 (>T1), the drum rotation speed is reduced. This drum dryer is characterized by comprising a control means for increasing the speed to N2 (>N0) and decreasing the drum rotation speed to N1 after a predetermined period of time.

[0005]

[Operation] In the early stage of drying, the drum is rotated at the optimum drum rotation speed N0. After that, when the drum exhaust temperature of the circulating air for drying reaches T1, the drum rotation speed is reduced from N0 to N1 (N1<N0).

[0006] Also, in the late drying stage, the drum exhaust temperature reaches T.
When reaching 2, the bulk of the cloth increases and it becomes difficult for the drying air to contact the center of the cloth, so the drum rotation speed should be changed from N1 to N2 (N2
>N0>N1), attach a cloth to the inner periphery of the drum, and create a gap in the center to allow drying air to pass through. By doing so, drying of the center portion where the drying rate is slow is promoted, and drying time can be shortened and efficiency can be increased.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on embodiments shown in the drawings. This invention is not limited thereby.

FIG. 1 is a schematic sectional view showing a drum type washer/dryer according to an embodiment of the present invention. In FIG. 1, a drum type washer/dryer 1 includes a heat exchanger 4 for removing air discharged from the drum 2, a blower fan 12 for blowing the dehumidified air, and a blower fan 12 for blowing the dehumidified air. A heater 3 is provided to heat the blown air. Then, a heat exchanger 4, a blower fan 12, a heater 3
By connecting the drum 2 and the drum 2 in a closed loop via the air duct 8, air is circulated through the drum 2 and the laundry inside is heated and dehumidified. drum 2
A circulation air path is formed by a blower duct 8 along the outside of the water tank 13 disposed near the outside of the water tank 13, and the ends of this circulation air path are connected to the air outlet 24 and the suction port 25 of each water tank 13. Ru. The heat exchanger 4 is air-cooled by a cooling fan 5 attached near the heat exchanger 4, and cools and dehumidifies the air circulating in the circulation air path. That is, heat exchanger 4, blower fan 1
2, heater 3, and cooling fan 5 are dehumidifying and heating means. Note that the circulation air passage is located at a position that does not pose a problem when loading and unloading laundry into the drum 2.

[0009] The outer peripheral end of the drum 2 on the right side in FIG. On the other hand, a bead 9 is formed on the side wall of the water tank 13 facing the side wall 2a of the drum 2. The bead 9 is formed to have a slightly smaller diameter than the inner diameter of the overhang 10 and is configured to fit with the overhang 10 without contacting it. Further, a large number of ventilation holes 11 are bored in the side wall 2a of the drum 2 so as to guide dry air from the air outlet 24 into the drum. The water tank 13 has a spring 18 inside the case 14.
and is supported by a buffer 19.

The drum 2 is rotatably supported in a water tank 13 by a shaft 7, and is driven by pulleys 27 and 28 by a motor (DC brushless motor) 15 provided at the bottom of the water tank 13.
and is driven via a belt 29. Laundry is on lid 2
1, 22, and 23 are opened and put into the drum 2. 20 is a baffle provided on the inner circumferential surface of the drum 2 for lifting laundry; 17 is a water hole bored in the drum peripheral wall; 16
is a drain valve, and 6 is a water supply valve.

FIG. 2 is a block diagram showing the control section of the embodiment shown in FIG.
26 is a thermistor provided in the air duct 8 to detect the exhaust temperature of the drum 2. Microcomputer MC receives outputs from operation panel P and thermistor 26, and drives heater 3, ventilation fan 12, cooling fan 5, motor 5, water supply valve 6, and discharge valve 16.

When carrying out washing and drying operations using the drum-type washer/dryer 1, first the laundry is placed in the lids 21, 22,
23 and into the drum 2, washing and rinsing operations similar to those of the prior art are carried out. When the rinsing operation is completed, the rinsing water in the water tank 13 is discharged through the drain valve 16, and then the drum 2 rotates at high speed to perform a dewatering operation using its centrifugal force.

The drying operation in the drum washer/dryer 1 will be explained using the flowchart shown in FIG. 3 and the graph of tram exhaust temperature change shown in FIG. 4. When the drying operation is started, the motor 15 whose rotational speed can be controlled, the blower fan 12, the cooling fan 5, and the heater 3 are energized, and the air sucked into the blower duct 8 from the suction port 25 of the water tank 13 is transferred to the heat exchanger 4. The air is dehumidified by the heater 3, and heated by the heater 3 to become high-temperature dry air.
4 into the water tank 13. In this case, the overhang 1
Since the drum 2 and the water tank 13 are slightly sealed by the drum 2 and the beat 9, the high temperature dry air from the air outlet 24 is almost forced into the drum 2 through the ventilation hole 11 of the drum 2. be done. The highly dry air blown into the drum 2 evaporates the moisture contained in the laundry, resulting in a low temperature and high humidity state. Then, the dry air is blown out from the small holes 17 in the peripheral wall of the drum 2 to the water tank 13 and returns to the air inlet 25 again. At this time, as the drum 2 rotates at a rotational speed N0, the laundry in the drum 2 is lifted by the baffle 20 to the vicinity of the top of the drum 2, and is then loosened as it falls under its own weight, and is uniformly heated to a high temperature. (Steps 101 to 104)
. The moisture condensed in the heat exchanger 4 is discharged to the outside through a drainage path (not shown) connected to the heat exchanger 4. After that, the exhaust temperature from the drum 2 detected by the thermistor 26 disposed in the air duct 8 is shown in FIG.
When T1 is reached (step 105), motor 1
By controlling the rotation speed of No. 5, the drum rotation speed is slightly decreased from N0 to N1 (step 106).
. By doing so, the contact time between the drying air and the laundry is increased and the contact factor is improved. Also, N
A rotation speed of 1 is such that the laundry is lifted to a sufficient position by the baffle 20, and should not be so low that the laundry becomes a roll. In the latter stage of drying, that is, during lapse rate drying, the bulk of the laundry increases and the drying air does not come into contact with the center, so when the exhaust temperature from drum 2 reaches T2, the drum rotation speed is increased from N1 to N2. A cloth is pasted around the outer circumference of the drum to create a gap in the center to allow dry air to pass through. Note that the time for setting the drum rotation speed to N2 is t1 (min), and the period is t0 (min).
) (steps 107 to 109). Then, when the drum exhaust temperature reaches T3 (step 110), the heater 3, the blower fan 12, the cooling fan, and the DC brushless motor 15 are de-energized, and the drying is completed (step 1).
11-114). Note that specific numerical examples of the above embodiments are as follows. Weight of laundry = 5kg (dry) NO = 55rpm, N1 = 50rpm, N2 = 120r
pm T1=60°C, T2=68°C, T3=78°Ct1
=2min, t0=10min

[0014]

[Effect of the invention] According to this invention, 1. During the drying process, the drum can be operated at an optimal rotational speed at all times, which prevents the laundry from becoming rolled or tangled. 2. By rotating the drum at a higher speed than usual, attaching the laundry to the outer periphery of the drum, and passing drying air through the center, uneven drying is drastically reduced and local heating of the laundry is prevented. 3. Not only is the drying efficiency for laundry improved and the drying time shortened, but the performance of low bath ratio drying is dramatically improved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the configuration of a drum-type washer/dryer showing an embodiment of the present invention.

FIG. 2 is a block diagram of a control section of the embodiment shown in FIG. 1;

FIG. 3 is a flowchart of the drying process of the embodiment shown in FIG. 1;

FIG. 4 is a graph showing changes over time in the drum exhaust temperature of the embodiment shown in FIG. 1;

[Explanation of symbols]

1. Drum-type washer/dryer 2 Drums 3 Heater 4 Heat exchanger 5 Motor 6 Thermistor

Claims (1)

[Claims] Claim 1: A drum dryer configured to circulate dehumidified warm air through a rotating drum, comprising: a temperature sensor that detects the temperature of exhaust gas from the drum; and a temperature sensor that changes the rotational speed of the drum. After the driving means and the drum start operating at the rotational speed N0, the exhaust temperature of the drum rises to T.
When the temperature reaches 1, the drum rotation speed is reduced to N1 (<N0), and the drum exhaust temperature further increases to T2 (>T1).
1. A drum dryer comprising: control means for increasing the drum rotational speed to N2 (>N0) when the drum rotational speed reaches N2 (>N0) and decreasing the drum rotational speed to N1 after a predetermined period of time.