Patent Grant
10640911
The invention relates to a method of controlling a drying cycle for drying delicate laundry in a laundry drying apparatus, in particular in a dryer or in a washer dryer. Further the invention relates to a laundry drying apparatus having a control unit adapted to control the execution of a drying cycle.
EP 1 699 971 B1 discloses a laundry drying apparatus having a rotatable drum adapted to receive laundry to be dried. A control unit is provided to control the drying cycle. The drying cycle has an anti-crease phase in which the laundry is periodically moved and periodically not moved. The movement of the laundry during the anti-crease phase is dependent on specific parameters like progressing time, laundry temperature or residual humidity of the laundry. The anti-crease phase shall avoid creases in the laundry.
It is an object of the invention to provide a method of controlling a drying cycle for drying delicate laundry in a laundry drying apparatus such that delicate laundry is treated gently. It is a further object of the invention to provide a laundry drying apparatus implementing the method.
A laundry drying apparatus—in the following description also denoted in brief “apparatus”—that is to be used for the invention comprises a cabinet and a drum adapted to receive laundry to be dried. The drum is rotatable supported in the cabinet. Furthermore, the apparatus comprises a drying air channel arrangement designed to guide drying air such that it passes through the drum for drying the laundry within the drum. A heating element is arranged in the channel arrangement for heating the drying air and a blower arranged in the channel arrangement is adapted to convey the drying air. A drum motor is adapted to rotate the drum selectively in a main rotation direction and in a counter rotation direction.
The method of an aspect of the invention provides controlling a drying cycle for drying delicate laundry comprising a predefined drying phase sequence having at least the following phases:
Within this predefined drying phase sequence the first average flow rate is lower than the second average flow rate.
The drying phase sequence contributes to a smooth and gentle mechanical treatment of delicate laundry. The aforementioned rotation of the drum is able to control movements of the treated laundry such that delicate laundry will be dried gently and simultaneously creases can be avoided or at least reduced to a minimum.
During the second drying phase, the drum rotation is preferably such that the drum is rotating only or mainly in the main rotation direction.
Preferably, the drying cycle or drying program (which can be also denoted as “drying process”) includes the drying phase sequence, i.e. the first and second drying phases, at least one time. Preferably, the whole drying phase sequence is executed at least five, ten, twenty or thirty times during the drying process.
The desired lower first average flow rate is preferably realized by a blower designed to have a conveying capacity which is reduced when the drum is rotated in counter rotation direction with a same rotation speed as in the main rotation direction and/or which is designed to convey less air in the forward blower conveyance direction than when operated with the same rotation speed in the rearward blower conveyance direction. In particular, a drum motor may simultaneously be the motor for driving the blower.
In reverse, the mechanical treatment or agitation of the delicate laundry is higher during the second drying phase due to the higher second average flow rate during the second drying phase. This succession of the different drum rotations and average flow rates supports avoiding creases in delicate laundry.
In an embodiment the heating element for heating the drying air is constituted for example as an electrical resistance heater or as a refrigerant cooling element (condenser) of a heat pump system in a heat pump laundry treatment apparatus.
A heat pump laundry treatment apparatus is particularly suitable or adapted to carry out the drying phase sequence for drying gently delicate laundry since this apparatus provides drying air with low temperature which supports smooth and gentle treatment of delicate laundry during the anti-crease phase.
The apparatus may be a vented dryer, however preferably the apparatus is a condensation dryer. Preferably the apparatus is a tumble dryer. The rotation axis of the drum is preferably a horizontal or essentially horizontal drum axis. Alternatively, the rotation axis of the drum is inclined relative to the horizontal plane by 5°-50°, preferably 10°-40°, particularly 20°-35°.
The aforementioned drying process is particularly suitable for gently treating all kind of delicate laundry, particularly silk. The delicate laundry can be defined in general as laundry requiring to be dried by lower or more delicate mechanical agitation than laundry in a usual drying process.
In a preferred embodiment, the drying cycle in general or the first drying phase or the second drying phase is ended, when one or more predetermined conditions is/are detected which indicate(s) the laundry status. The one or more predetermined conditions are preferably at least one of the following conditions:
Preferably, a cooling phase is started when the one or more predetermined conditions is/are detected. Particularly, this cooling phase is a final portion of the whole drying cycle.
When the one or more predetermined conditions is/are detected, the heating element for heating the drying air may be automatically switched off or deactivated. Nevertheless, conveying air through the drum is preferably continued during the cooling phase.
Preferably, all or most rotation periods of the alternating main rotation direction and counter rotation direction during the first drying phase have a duration such that the drum is rotated less than 5 full turns or less than 3 full turns or less than 1 full turn or less than a half turn. The specific number of turns during a rotation period depends on the drum speed (rpm, rounds or turns per minute) and the defined time period. For example, one rotation period corresponds to a duration of 4 or 5 seconds. A preferred drum speed during the rotation period is 12 rpm. In another example, the duration of a rotation period is 2 seconds and the drum rotation speed during this rotation period is 54 rpm. This results in number of turns less than 2 turns, i.e. approximately 1.8 turns.
Defining rotation periods and/or the first drying phase by the aforementioned parameters allows shorter drum rotation times at lower drum rotation speed in both rotation directions (main and counter) thus providing a more delicate treatment of the laundry while enhancing its mechanical agitation and redistribution in the drum. This offers delicate laundry to be dried very gently in a shorter time.
In embodiments the first drying phase exhibits at least one of the following (alternative or additional) features:
This asymmetric or unequal drum rotation in one of both rotation directions (main and counter) supports improved laundry distribution in the drum.
Preferably the maximum drum rotation speed during the second drying phase is higher than the maximum drum rotation speed during the first drying phase. Such a drum rotation control during the drying phase sequence provides enhanced treatment of delicate laundry to be dried.
Preferably, the maximum drum rotation speed in the first drying phase is
Preferably, the maximum drum rotation speed in the second drying phase is
The satellization speed is the speed where laundry adheres to the drum wall during drum rotation.
In an embodiment the drying air channel arrangement of a drying apparatus according to the invention is designed such that the drying air is guided from at least one drum outlet to at least one drum inlet in such a manner that the drum and the drying air channel form a drying air loop. Preferably such arrangement is used in a condenser-type and/or heat-pump system dryer.
Preferably, a cooling phase for cooling the delicate laundry during a final portion of the drying cycle is provided and/or an anti-crease phase after the drying cycle is provided. In this cooling phase and/or anti-crease phase, a so called third phase is applied (executed) in which the drum is rotated alternately in the main and the counter rotation direction while the drying air is conveyed at the first average flow rate through the drum or at another average flow rate lower than the second average flow rate. Applying such a third phase supports the aim of a drying cycle to dry the laundry according to a predetermined condition, e.g. according to a predetermined humidity level like cupboard dry, ironing dry or damp.
The cooling phase may be considered as part of the drying cycle, whereas the anti-crease phase may be considered as an additional cycle. This additional cycle is executed preferably automatically if the laundry is detected as not being removed by the user.
Preferably, the third phase is or is essentially like or similar to the first drying phase. Particularly, the third phase has the same or essentially the same physical parameters like the aforementioned first drying phase. In further embodiments, the third phase is executed repetitively during the cooling phase and/or anti-crease phase periodically or from time to time.
In an embodiment, a cooling phase for cooling the delicate laundry during a final portion of the drying cycle is provided and/or an anti-crease phase after the drying cycle is provided, wherein a so called fourth phase is applied in this cooling phase and/or anti-crease phase. In the fourth phase the drum is rotated or at least mainly rotated in the main rotation direction while the drying air is conveyed at the second average flow rate through the drum or at another average flow rate higher than the first average flow rate.
Preferably, the fourth phase is or is essentially like or similar to the second drying phase. Particularly, the fourth phase has the same or essentially the same physical parameters like the aforementioned second drying phase. In further embodiments, the fourth phase is executed repetitively during the cooling phase and/or anti-crease phase periodically or from time to time.
Preferably during the cooling phase and/or anti-crease phase, both the third and fourth phases are applied. Preferably the third/fourth phases are repeated as the repetition of the first/second phase.
At least a portion of the drying phase sequence, particularly the whole drying phase sequence, can be executed in an anti-crease phase of the drying cycle. The drying phase sequence can be regarded as a part of an anti-crease phase. In particular, an anti-crease phase is constituted by the drying phase sequence. Preferably, the drying phase sequence is executed repetitively during the drying cycle, in particular during the anti-crease phase.
Especially,—and apart from the heating element controlled to be switched off or deactivated—all parameters (e.g. maximum drum rotation speed, rotation period, etc.) applied for the first and second drying phase are also applicable for the third and fourth phase, respectively.
In a preferred embodiment the duration of the fourth phase is shorter than the duration of the second drying phase. Particularly, the ratio of the duration of the fourth phase to the duration of the second drying phase is equal to or below 0.5, 0.4, 0.2, 0.1, 0.05 or 0.02. For example, the duration of the fourth phase is or is about 180, 120, 100, 80, 60, 50 or 40 seconds.
Preferably, the heating element is switched off or deactivated in a cooling phase for cooling the delicate laundry during the final portion of the drying cycle or during an anti-crease phase after the drying cycle.
The heating element is preferably switched off or operated at reduced power during the first drying phase or at least temporarily during the first drying phase. Due to such control of the heating element, potential overheating of the temperature sensitive delicate laundry (particularly silk) is prevented in a facile technical manner. Such control is especially beneficial in case of an electric heater because the state of switch off or reduced power is able to be achieved very fast even if the generated temperature for heating the drying air was relative high. In case the apparatus contains a heat pump system having a compressor, controlling of the compressor would preferably continuously operate as the temperature of the drying air entering the drum is relative low (e.g. 50-55° C.). Insofar here potential overheating of delicate laundry is avoided.
In a further preferred embodiment, a drying apparatus according to the invention comprises a heat pump system having a refrigerant cooling element (e.g. a condenser) as the heating element for heating the drying air. Further this heat pump system has a refrigerant heating element for cooling the drying air arranged in the drying air channel arrangement upstream the heating element. The compressor of the heat pump system is preferably switched off during the cooling phase and/or anti-crease phase. The residual drying capacity of the refrigerant is used in an energy-saving manner in the cooling phase.
In another embodiment the drum rotation is stopped during the first drying phase for defined time periods between a reversal between rotation in main rotation direction and counter rotation direction. This stopped drum rotation period (also denotable as “stop period”) is not executed necessarily between all drum rotation reversals but in a preferred embodiment between at least most drum rotation reversals during the first drying phase. Particularly, the stop period has a duration of at least 1, 2, 3, 5, 8 or 10 seconds.
As already mentioned, the delicate laundry, on which the inventive method of the present invention is applied, is particularly silk. Preferably, the method according to the invention is activated or selected to be performed in a drying apparatus through an input unit adapted to receive a request or input by a user to activate a delicate, particularly silk, drying treatment program. This delicate, particularly silk, drying treatment program includes controlling the apparatus according to the method having any of the aforementioned features.
The drum motor adapted to rotate the drum is preferably a controllable speed motor such that, in the method according to the invention, the drum may be rotated at different predetermined speeds by a control unit. Thus, the described first, second, third and fourth phases can be precisely executed in a facile manner.
In order to support the efficiency of the laundry treatment, the blower of a drying apparatus according to the invention is designed such that the conveyance capacity of the blower is higher when the blower is rotated in the forward direction as compared to rotation at the same speed in the backward direction. The drum motor may be simultaneously used as the motor for rotating the blower. In this regard, the main rotation direction of the drum corresponds to the forward direction of the blower.
According to another aspect of the invention, a laundry drying apparatus (in particular a dryer or washer-dryer) is provided and is generally adapted to implement or carry out a drying cycle. Particularly, this laundry drying apparatus (in brief denotable again “apparatus”) has a control unit programmed for carrying out a drying cycle according to any of the above or below described aspects of the method. This apparatus may have individually or in combination any feature(s) disclosed in conjunction with the description and/or the figures.
Preferably, this laundry drying apparatus comprises a cabinet and a drum adapted to receive laundry to be dried, wherein the drum is rotatable supported in the cabinet. A drying air channel arrangement is designed to guide drying air such that it passes through the drum for drying the laundry in the drum. A heating element is arranged in the channel arrangement for heating the drying air and a blower is arranged in the channel arrangement adapted to convey the drying air. A drum motor is adapted to rotate the drum selectively in a main rotation direction and in a counter rotation direction.
Additionally, the drying apparatus comprises a control unit particularly adapted, i.e. programmed, to control the execution of at least one drying cycle according to the method of the present invention. In particular, the execution of said at least one drying cycle has at least one drying phase sequence with a first and a second drying phase. In the first drying phase the control unit controls the drum motor to rotate the drum alternately in the main and the counter rotation direction, and to control the blower such that the drying air is conveyed at a first average flow rate through the drum. In the second drying phase the control unit controls the drum motor to rotate or mainly rotate the drum in the main rotation direction, and to control the blower such that the drying air is conveyed at a second average flow rate through the drum, wherein the first average flow rate is lower than the second average flow rate.
An apparatus configured in the aforementioned way and/or having a control unit implementing any of the aforementioned method features provides the advantages as described above and/or below. In particular the apparatus provides a more efficient or improved operation with respect to the desired gentle treatment of delicate laundry.
Reference is made in detail to preferred embodiments of the invention, an example of which is illustrated in the accompanying figures which show:
The drying air flow within the apparatus 2 is guided through a compartment 18, e.g. a laundry drum, of the home appliance 2, i.e. through a compartment for receiving articles to be treated. The articles to be treated are textiles, particularly delicate laundry 19, or the like. The drying air flow is indicated by arrows A in
As shown in
Preferably the control unit 52 is at the same time the control unit for controlling and monitoring the overall operation of the apparatus 2. The tumble dryer 2 according to
As shown in
Regarding the drying air flow A, the drying air A is conveyed at a first average flow rate through the drum 18 when the first drying phase 62 is executed. When the second drying phase 64 is executed, the drying air A is conveyed at a second average flow rate through the drum 18, wherein the first average flow rate is lower than the second average flow rate.
In the detailed embodiment, the reduced flow rate is achieved by reduced ratio of rotating the drum in the main rotation direction. Due to driving the blower 8 with the drum motor 54 and due to a higher conveyance capacity of the blower in the forward direction (when the drum is rotating in main rotation direction), when the ratio of drum rotation in the main rotation direction is lower, the blower conveyance capacity is also lower. In other embodiments the blower may be driven independently of the drum and the control unit 52 may control the blower operation such that there is a lower average air flow in the first drying phase. In another embodiment the blower may have same or similar conveyance capacity in forward and backward direction and may be driven by the drum motor, however by alternating in the main and counter rotation direction, the repeatedly reverting air flow direction is at least partially mutually extinguishing due to respective counter-inertia.
The first drying phase 62 and/or the second drying phase 64 may be ended when one or more predetermined conditions is/are detected. This at least one predetermined condition may indicate a laundry status or is the termination of set time period(s).
The first drying phase 62 has several stop periods 68 in which rotation of the drum 18 is stopped for specific time periods between rotation reversals from the main rotation direction 58 to the counter rotation direction 66 and vice versa.
In the present example, the time durations, the allocated drum speeds and rotation directions are as follows:
The above sequences, time durations, rotation speeds, provision of stop periods are exemplary only.
The described first drying phase 62 has an overall duration of 28 seconds. During this first drying phase 62 the total duration of drum rotation in the counter rotation direction 66 is longer (=9 seconds) than the total duration of drum rotation in the main rotation direction 58 (=5 seconds). The duration of the rotation period 70 in the main rotation direction 58 is longer (=5 seconds) than the duration of the first rotation period 70 in the counter rotation direction 66 (=4 seconds). The number of rotation periods 70 rotating the drum 18 in counter rotation direction 66 is higher (i.e. two rotation periods 70) than the number of rotation periods 70 rotating the drum 18 in main rotation direction 58 (i.e. one rotation period).
Preferably, this whole drying phase sequence 60 is repeated immediately one time or several times till the end of the whole drying cycle. Alternatively, a repeated drying phase sequence is executed only in part. A final portion of the drying cycle may be constituted as a cooling phase for cooling the delicate laundry. Alternatively or additionally, an anti-crease phase for treating the delicate laundry may be executed after the drying cycle.
The proposed drying phase sequence 60 is able to provide a more gently and smooth treatment of delicate laundry during a drying cycle in order to achieve dried and crease-resistant delicate laundry like silk. On the other hand, the delicate laundry is particularly gently dried in a shorter time.
| Number | Date | Country | Kind |
|---|---|---|---|
| 14174766 | Jun 2014 | EP | regional |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/EP2015/064519 | 6/26/2015 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2015/197816 | 12/30/2015 | WO | A |
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| Entry |
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| English translation of Chinese Office Action for Chinese Application No. 201580027717.8, dated Jul. 9, 2018, 9 pages. |
| Number | Date | Country | |
|---|---|---|---|
| 20170130389 A1 | May 2017 | US |
