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CN-115698417-B - Method for operating a laundry dryer equipped with a heat pump system and laundry dryer implementing said method

CN115698417BCN 115698417 BCN115698417 BCN 115698417BCN-115698417-B

Abstract

The invention relates to a method for controlling a laundry dryer (1; 201) equipped with a heat pump system (50) during a drying cycle. The laundry dryer (1; 201) comprises a control unit (UC 1), a rotatable treatment chamber (9) into which laundry can be put for drying with a drying air flow, a heat pump system (50) comprising a compressor (52), a passive switching device (70) controllable by the control unit (UC 1) and adapted to cut off power supplied to the compressor (52), and an active switching device (72) controllable by the control unit (UC 1) for selectively switching the compressor (52) on and off. The method comprises the steps of starting a drying cycle, enabling the heat pump system (50) by switching on the compressor (52), rotating the process chamber (9), evaluating whether a reversal of the direction of rotation of the process chamber (9) has to be performed, if a reversal of the direction of rotation has to be performed, evaluating whether there is an operating condition that can result in the compressor (52) of the passive switching device (70) being enabled, if there is no operating condition, performing a reversal of the direction of rotation of the process chamber (9), otherwise if there is an operating condition, performing the steps of switching off the compressor (52), performing a reversal of the direction of rotation of the process chamber (9), switching on the compressor (52).

Inventors

  • Mattia Sesolo
  • Christian Zava
  • RAGOGNA ROBERTO
  • ALESSANDRO RICCI
  • Alexandro Dalarosa

Assignees

  • 伊莱克斯家用电器股份公司

Dates

Publication Date
20260512
Application Date
20210521
Priority Date
20200605

Claims (19)

  1. 1. Method for controlling a laundry dryer (1; 201) equipped with a heat pump system (50) during a drying cycle, the laundry dryer (1; 201) comprising: -a control unit (UC 1); -a treatment chamber (9) into which laundry can be put for drying with a drying air flow, said treatment chamber (9) being adapted to rotate; -a heat pump system (50) comprising a compressor (52), a first heat exchanger (54) for cooling a refrigerant and heating the air stream, an expansion device (58) and a second heat exchanger (56) for heating the refrigerant; -at least one passive switching device (70) which can be controlled independently of the control unit (UC 1) and which is adapted to cut off the power supplied to the compressor (52) when one or more predetermined operating parameter thresholds are exceeded; -at least one active switching device (72) controllable by the control unit (UC 1) for selectively switching the compressor (52) on and off; Wherein the method is characterized in that it comprises the steps of: -starting a drying cycle; -enabling the heat pump system (50) by switching on the compressor (52); -rotating the treatment chamber (9); -evaluating whether a reversal of the direction of rotation of the process chamber (9) has to be performed, and if so, whether there are operating conditions that can lead to the activation of the compressor (52) of the passive switching device (70); -if said operating condition is not present, performing a reversal of the direction of rotation of said process chamber (9), otherwise if said operating condition is present, performing the following steps: a) -switching off the compressor (52); b) -performing a reversal of the rotation direction of the process chamber (9); c) The compressor (52) is switched on.
  2. 2. The method of claim 1, wherein the step of evaluating whether there are operating conditions that can result in enabling the compressor (52) of the passive switching device (70) comprises evaluating one or a combination of the following conditions: -whether the operating temperature (To) of the laundry dryer (1; 201) is higher than a first threshold operating temperature (T1), wherein the operating temperature (To) of the laundry dryer (1; 201) is detected by at least one temperature sensor (80); -whether the time elapsed since the start of the drying cycle is above a first time threshold (t 1); -whether the humidity (M) of the laundry or of the interior of the treatment chamber (9) is below a first threshold value (M1), wherein said humidity (M) is detected by at least one humidity sensor.
  3. 3. Method according To claim 2, characterized in that the operating temperature (To) of the laundry dryer (1; 201) is a refrigerant temperature (To), and said first threshold operating temperature (T1) is a first refrigerant threshold temperature.
  4. 4. Method according To claim 2, characterized in that the operating temperature (To) of the laundry dryer (1; 201) is the operating temperature and/or the ambient temperature and/or the drying air flow temperature of the heat pump system (50).
  5. 5. Method according to any one of claims 2 to 4, characterized in that the value of the first time threshold (t 1) depends on the type of drying cycle selected by the user.
  6. 6. Method according to any of claims 1 to 4, characterized in that the step of assessing whether reversal of the direction of rotation of the process chamber (9) has to be performed comprises a step of taking into account the scheduling time for reversal of the direction of rotation of the process chamber (9) according to the type of drying cycle selected by the user.
  7. 7. The method according to any one of claims 1 to 4, characterized in that said step of assessing whether reversal of the direction of rotation of said treatment chamber (9) has to be performed comprises the step of determining during the drying cycle the presence of one or a combination of the following conditions of the laundry dryer (1; 201) requiring reversal of the direction of rotation of the treatment chamber (9), load imbalance, humidity (M) of the laundry reaching a pre-fixed value, humidity (M) inside the treatment chamber (9) reaching a pre-fixed value, reversal of the direction of rotation of the drying air circulation fan (28).
  8. 8. Method according to any one of claims 1 to 4, characterized in that said step a) of switching off said compressor (52) is performed before or simultaneously with said step b) of performing a reversal of the direction of rotation of said process chamber (9), and said step c) of switching on said compressor (52) is performed after said step b) of performing a reversal of the direction of rotation of said process chamber (9).
  9. 9. Method according to claim 8, characterized in that said step c) of switching on said compressor (52) is performed after said step b) of performing a reversal of the rotation direction of said process chamber (9) is started.
  10. 10. Method according to claim 8, characterized in that said step c) of switching on said compressor (52) is performed after said step b) of performing a reversal of the rotation direction of said treatment chamber (9) is completed.
  11. 11. The method according to any one of claims 1 to 4, characterized in that said step a) of turning off said compressor (52) is performed after said step b) of performing a reversal of the direction of rotation of said process chamber (9), and said step c) of turning on said compressor (52) is performed after said step a) of turning off said compressor (52).
  12. 12. Method according to claim 11, characterized in that said step a) of switching off said compressor (52) is performed after said step b) of performing a reversal of the rotation direction of said process chamber (9) is started.
  13. 13. Method according to claim 11, characterized in that said step a) of switching off said compressor (52) is performed after said step b) of performing a reversal of the rotation direction of said process chamber (9) is completed.
  14. 14. Method according to claim 11, characterized in that said step a) of switching off said compressor (52) is performed within a first delay time (DT 1) after said step b) of performing a reversal of the rotation direction of said process chamber (9) has been started or ended.
  15. 15. The method according to any one of claims 1 to 4, characterized in that said step b) of performing a reversal of the direction of rotation of said process chamber (9) is performed after said step c) of switching on said compressor (52), and said step a) of switching off said compressor (52) is performed before said step c) of switching on said compressor (52).
  16. 16. Method according to claim 15, characterized in that said step b) of performing the reversal of the direction of rotation of said process chamber (9) is performed within a second delay time (DT 2) after said step c) of switching on said compressor (52).
  17. 17. The method according to claim 1 or claim 2, characterized in that the laundry dryer (201) comprises at least one compressor cooling fan (60), and in that the method comprises the steps of: d) Detecting an operating temperature (To) of the laundry dryer (1; 201); e) -switching on said cooling Fan (60) if the detected operating temperature (To) of the laundry dryer (1; 201) is higher than a switching-on threshold temperature (fan_ton); f) If the detected operating temperature (To) of the laundry dryer (1; 201) is lower than a shut-off threshold temperature (fan_toff), the cooling Fan (60) is turned off.
  18. 18. A laundry dryer (1; 201) equipped with a heat pump system (50), said laundry dryer (1; 201) comprising: -a control unit (UC 1); -a treatment chamber (9) into which laundry can be put for drying with a drying air flow, said treatment chamber (9) being adapted to rotate; -a heat pump system (50) comprising a compressor (52), a first heat exchanger (54) for cooling a refrigerant and heating the air stream, an expansion device (58) and a second heat exchanger (56) for heating the refrigerant; -at least one passive switching device (70) which can be controlled independently of the control unit (UC 1) and which is adapted to cut off the power supplied to the compressor (52) when one or more predetermined operating parameter thresholds are exceeded; -at least one active switching device (72) controllable by the control unit (UC 1) for selectively switching the compressor (52) on and off; characterized in that the control unit (UC 1) is configured to control the rotation of the compressor (52), and of the treatment chamber (9), according to the method of any one of claims 1 to 17.
  19. 19. The laundry dryer (1; 201) according to claim 18, characterized in that the laundry dryer further comprises at least one temperature sensor (80) and/or at least one humidity sensor.

Description

Method for operating a laundry dryer equipped with a heat pump system and laundry dryer implementing said method Technical Field The present invention relates to the field of laundry dryers equipped with a heat pump system, and more particularly to a method for operating such a machine during a drying cycle. Background A laundry dryer (hereinafter abbreviated as dryer) capable of performing a drying process on laundry generally includes a housing accommodating a processing chamber (preferably a rotary drum) in which laundry to be processed is accommodated. The closed air flow circuit performs a drying operation by circulating hot air through the treatment chamber containing wet laundry. The present invention can be effectively applied to all machines that perform a drying process on laundry or wet laundry, such as a laundry washing-drying combination machine. Thus, in the present specification, the term "laundry dryer" will refer to a simple laundry dryer or a laundry washer-dryer. In clothes dryers, heat pump technology is the most efficient way to save energy in the drying process/cycle. In a conventional heat pump dryer, the drying air flow flows in a closed loop. The drying air flow is moved by a fan through a rotating drum and removes water from the wet clothing. The drying air flow is then cooled and dehumidified in the heat pump system and then heated and finally fed again into the laundry drum. The heat pump system includes refrigerant flowing in a closed loop refrigerant circuit implemented with piping and including a compressor, a condenser, an expansion device, and an evaporator. The condenser heats the dry air, while the evaporator cools and dehumidifies the dry air exiting the drum. The refrigerant flows in a refrigerant circuit in which the refrigerant is compressed by a compressor, condensed in a condenser, expanded in an expansion device, and then vaporized in an evaporator. Clothes dryers of known type are typically equipped with overload protection means in order to prevent damage to the compressor. The overload protection device typically used in clothes dryers preferably includes a passive switch that interrupts power supplied from the main line to the heat pump compressor when a predetermined compressor thermal temperature threshold or voltage load or sink current threshold is exceeded. The passive switch is opened when a threshold temperature of the heat pump compressor is reached and/or when a current through the passive switch is reached. When normal operating conditions are re-established, the passive switch (e.g. the thermal protector device) is adapted to return to an operating state where the electrical circuit is closed in order to supply the compressor with electrical power again. However, due to the large inertia of the overload protection apparatus to return to the closed position, there is a considerable delay, typically about 40 minutes, before the apparatus returns to the operational state. The disadvantage of this known technique therefore stems from the fact that the intervention of the overload protection device results in an increase in the duration of the drying cycle and thus in customer dissatisfaction. It is an object of the present disclosure to overcome at least some of the problems associated with the prior art. It is an object of the present invention to achieve a system for a laundry dryer equipped with a heat pump system adapted to prevent activation of overload protection means. Another object of the present invention is to achieve a system for a laundry dryer equipped with a heat pump system adapted to prevent an undesired extension of the drying cycle duration. Disclosure of Invention The applicant has found that the drawbacks of the known systems can be solved by providing a laundry treatment machine with a rotating treatment chamber, a heat pump system comprising a compressor, at least one passive switching device, which is adapted to cut off the power supplied to the compressor, which is not controllable by the control unit, and by providing a method in which the compressor is temporarily deactivated in time when reversal of the rotation of the treatment chamber has to be performed. According to one aspect of the present disclosure, there is provided a method for controlling a laundry dryer equipped with a heat pump system during a drying cycle as claimed in claim 1. Further features of the method according to the invention can be found in the dependent claims. In another aspect, the invention relates to a laundry dryer implementing the method according to the invention. Drawings Other features and advantages of the present invention will be highlighted in more detail in the following detailed description of the preferred embodiments of the invention provided with reference to the accompanying drawings. In the drawings: Figure 1 shows an isometric view of a laundry dryer in which the method of the invention may be implemented; Figure 2 is a schematic re