Method to control operation of a laundry dryer

Abstract

A method to control operation of a laundry dryer. The method includes starting a drying cycle, and receiving a user input command through one of a first interface and a second interface. If the command is provided through the first interface, a first working routine is started. If the same command is provided through the second interface, a second working routine is started. The second routing is different in at least one operational parameter than the first working routine. A laundry dryer configured to perform the method is also provided.

Claims

1. A method to control operation of a laundry dryer comprising a control unit having a memory in which instructions for a drying cycle, a first working routine and a second working routine are stored, a first interface and a second interface, the first interface and the second interface being adapted to transfer a user input command received at the first interface or the second interface to the control unit for operating the laundry dryer, wherein the method comprises: starting a drying cycle; receiving a user input command to the control unit through the first interface or the second interface to modify the drying cycle, wherein: upon receiving the user input command through the first interface, starting the first working routine; and upon receiving the user input command through the second interface, starting the second working routine which differs from the first working routine in at least one operational parameter set for operating the laundry dryer.

2. The method according to claim 1, wherein the first interface is remote or separate from the laundry dryer.

3. The method according to claim 2, wherein the first interface is a portable communication end device adapted to receive and send data from/to the laundry dryer via a communication network.

4. The method according to claim 2, wherein the laundry dryer comprises a casing and the second interface comprises a control panel fixed to the casing.

5. The method according to claim 1, wherein the at least one operational parameter set comprises: a speed of a drum motor; a speed of a process air fan motor; a number of times in which the process air fan is switched ON or OFF per unit of time; a duration of the drying cycle; a duration of the first or second working routine; an activation temperature of the cooling device to cool a process air heater; a heating power provided by the process air heater; a direction of rotation of a laundry drum; or a number of reversals of the direction of rotation of the laundry drum per unit of time.

6. The method according to claim 1, further comprising issuing an interruption command to interrupt the drying cycle upon receiving the user input command to modify the drying cycle.

7. The method according to claim 1, wherein the first working routine comprises a first cooling phase having a first set of cooling phase operational parameters.

8. The method according to claim 1, wherein, upon receiving the user input command through the first interface, starting a first cooling phase if a temperature value indicative of a temperature of the laundry is above a first threshold.

9. The method according to claim 7, wherein the second working routine comprises, until a cycle resumption command is received, either: starting a second cooling phase having at least one operational parameter set differently from the first set of cooling phase operational parameters; or switching off one or more of: a process air fan motor, a drum motor, and a process air heater.

10. The method according to claim 8, further comprising continuing the first cooling phase until: a temperature value indicative of a temperature of the laundry is lowered below a second threshold; or a pre-determined time interval has elapsed.

11. The method according to claim 10, wherein the pre-determined time interval is selected based on one or more of: a type of textile of the laundry; a type of drying cycle selected; a duration of a drying cycle; one or more drum motor operative parameters; a temperature of an environment in which the laundry dryer is located; a weight of the laundry; a moment in time in which the drying cycle has been interrupted; a geographical location of a user sending the command; and a temperature of process air at a time of the interruption.

12. The method according to claim 8, wherein the second working routine comprises starting a second cooling phase having at least one operational parameter set differently from the first set of cooling phase operational parameters, and wherein the at least one operational parameter comprises one or more of: a process air temperature; a duration of the second cooling phase; a refrigerant temperature of a refrigerant circuit; a rotation speed of a laundry drum; and a temperature of the laundry.

13. The method according to claim 7, wherein the first set of cooling phase operational parameters includes disabling a process air heater.

14. The method according to claim 1, wherein the drying cycle has a predetermined duration, and wherein the method comprises, upon receiving a cycle resumption command: calculating a T.sub.spent equal to the time elapsed between a beginning of the drying cycle and the time at which the user input command was received; calculating a T.sub.pause equal to the time elapsed between the time at which the user input command was received and a time at which the cycle resumption command was received; and re-starting the drying cycle for a time which is a function of the predetermined duration, T.sub.spent and T.sub.pause.

15. The method according to claim 7, wherein the laundry dryer further comprises a process air heating device including a heat pump system having a refrigerant circuit in which a refrigerant can flow, the refrigerant circuit including a first heat exchanger where the refrigerant is cooled off, a second heat exchanger where the refrigerant is heated up, a compressor to pressurize and circulate the refrigerant through the refrigerant circuit, and a pressure-lowering device, and the first and/or second heat exchanger is configured to perform heat exchange between the refrigerant flowing in the refrigerant circuit and the process air, and a compressor fan configured to blow air towards the compressor; and wherein the first cooling phase comprises switching on the compressor fan to blow air towards the compressor during the first cooling phase.

16. The method according to claim 1, wherein the laundry dryer includes a selector adapted to select alternatively one of a plurality of drying cycles and the drying cycle comprises a selected one of the plurality of drying cycles; and wherein the method comprises selecting the first working routine as a function of the selected one of the plurality of drying cycles.

17. The method according to claim 16, wherein the selected one of the plurality of drying cycles comprises a first set of drying cycle operating parameters and the first working routine comprises a second set of drying cycle operating parameters, and wherein one or more of the second set of drying cycle operating parameters are the same as the first set of drying cycle operating parameters.

18. The method according to claim 17, wherein the one or more of the second set of drying cycle operating parameters that are the same as the first set of drying cycle operating parameters includes one or more of: laundry drum motor working parameters; laundry drum speed parameters; a number of reversals of rotation of the laundry drum per unit time; and a flow rate of a process air in the laundry drum.

19. The method according to claim 7, wherein the first working routine comprises: determining, for the first cooling phase: a laundry drum speed, a number of reversals of rotation of the laundry drum per unit time and a direction of rotation of the laundry drum; and performing the first cooling phase according to the determined laundry drum speed, number of reversals of rotation of the laundry drum per unit time and direction of rotation of the laundry drum.

20. The method according to claim 1, wherein the first interface includes one or more of a personal computer, a smartphone, a tablet or a non-transient memory storage having a computer program stored therein.

21. A laundry dryer comprising: a control unit having a memory in which instructions for a drying cycle, for a first working routine and a second working routine are stored; and a first interface and a second interface, both adapted to transfer a user input command received at the first or second interface to the control unit for operating the laundry dryer; wherein the control unit comprises a processor having non-transiently stored instructions to perform the method according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Reference is made in detail to preferred embodiments of the invention, examples of which are illustrated in the accompanying figures, where:

(2) FIG. 1 is a perspective view of a drying machine according to the invention,

(3) FIG. 2 is a schematic overview of some components of the drying machine of FIG. 1,

(4) FIG. 3 is a block diagram depicting some of the components of the drying machine of FIG. 1 providing signals to a control unit and/or being controlled by the control unit,

(5) FIG. 4 is an enlarged view of a detail of the drying machine of FIG. 1,

(6) FIG. 5 is a flow chart of the method of the invention, and

(7) FIG. 6 is a flow chart of an additional embodiment of the method of the invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

(8) FIG. 1 shows a perspective outer appearance of an exemplary laundry dryer 2. In this embodiment, the laundry dryer is a laundry dryer only, but in alternative embodiments the dryer function according to the control method is implemented by a laundry washer-dryer in which the rotatable drum is arranged in a tub and which provides a washing arrangement including (for example) a detergent dispenser, a heater for heating wash liquid and a drain pump for draining out of the liquids.

(9) As shown in FIG. 1, the laundry dryer 2 has an outer housing 4 or cabinet including a front wall 6. Further, the laundry dryer 2 includes a drum 16, where the laundry is positioned in order to be dried. At the front wall 6 a loading opening 8 is provided which is closed by a door 10, to access the drum 16. In the depicted embodiment, the laundry dryer is a front-loading laundry dryer having a horizontal drum rotation axis, but in alternative embodiments the drum may be inclined relative to the horizontal and vertical directions, or the dryer may be a vertical rotation axis dryer in which the drum rotates around a vertical axis and where top-loading is provided.

(10) The laundry dryer is connected to a first interface 100, in the present case a smartphone, which can send user input commands to the laundry dryer 2. The connection may be a connection according to the 4G standard or via the internet. On the smartphone an application (App) may be installed in order to send commands to the laundry dryer 2.

(11) The laundry dryer 2 includes a second interface, a control panel 12, arranged at the upper region of the front wall 6 and a condensate drawer 14 in which the condensate collected from drying is stored until removal by the user.

(12) Both first and second interface can be operated by a user, for example by manual control, in order to send commands to the laundry dryer. An enlarged view of the first and the second interface 100, 12 is given in FIG. 4.

(13) In the schematic diagram of components shown in FIG. 2, the drum 16 is arranged inside the housing 4, in which laundry 18 is received. The flow of process drying air A is indicated by the arrows, wherein the drying air A leaves the drum 16 at an outlet 24 and enters a process air channel 20 at the front channel 20c. By the front channel 20c the process drying air is guided through a fluff filter element 26 towards a second heat exchanger 34 and a first heat exchanger 32. The first and second heat exchangers 32, 34 are arranged in a battery channel 20a of the process air channel 20. The first heat exchanger 32 is a condenser which heats the process drying air and the second heat exchanger 34 is an evaporator which cools the process drying air for humidity removal in form of condensed water.

(14) The process drying air leaving the first heat exchanger 32 is entering a rear channel 20b in which a drying process air fan 28 is arranged which conveys the drying air. The process air fan 28 is driven by a motor 30, which preferably at same time drives the rotation of the drum 16. However two different motors can be provided as well. The rotation of the drum 16 can be in one direction and also in the opposite direction, that is, reversing the rotation of the drum is possible in the laundry dryer operation, by opportunely driving the drum driving motor. In the depicted embodiment, a belt driven by the motor 30 is wound around the drum mantel for driving the fan. In the depicted embodiment, in which the single motor 30 drives the process air fan 28 as well as the drum 16, the drum and process air fan 28 are driven in a synchronous manner according to the gear ratio. Preferably, the speed of the drum and/or the process air fan is adjustable. Synchronous rotation of the drum includes a forward and backward rotation according to the motor forward and backward rotation, so that the direction of rotation of the drum can also be changed, from a forward to a backward or vice versa. As an example, the fan speed is identical to the motor speed as the process air fan is arranged on an axis of the motor 30, while via the belt the rotation of the motor is gear-reduced in an exemplary ratio of motor rotation speed/drum rotation speed of 50:1.

(15) The first and second heat exchangers 32, 34 are part of a heat pump system 44 which further comprises an expansion device 38 and a compressor 36. In the heat pump system 44 a refrigerant loop 40 is formed, wherein the refrigerant pumped by the compressor 36 passes first the condenser 32, is forwarded to the expansion device 38 from where it expands into the second heat exchanger 34 and from where it is sucked into the compressor 36. Heat can be removed from the heat pump system (in addition to the heat deposited in the drying air and laundry for drying the laundry) by activating a compressor cooling fan 42 which provides a flow of cooling air from the outside of the cabinet 4 towards the outer surfaces of the compressor 36. The compressor cooling fan can be activated, that is, it can start blowing air against the compressor, for example above a given compressor temperature, and/or it may be deactivated, that is, it may stop blowing air against the compressor, for example below a given compressor temperature. In addition, the flow rate of the air moved by the compressor cooling fan 42 may be varied as well. After passing the compressor 36, the cooling air blown by the compressor cooling fan 42 is exhausted out of the cabinet 4.

(16) The condensate that is formed at the evaporator 34 flows down and is collected in a condensate collector 48. From the condensate collector 48 the condensate is pumped by a draining pump 50 through a drain conduit 52 into the condensate drawer 14 from where it can be removed by the user as mentioned above. Preferably, in the condensate collector 48, the level of water can be measured by means of a level sensor and/or the temporal gradient of a level of water removed from the outdoor textile to be dried and collected can be measured as well.

(17) One or more of the following can be present in the laundry dryer as well: at the outlet 24 of the drum 16 a temperature sensor, for example a thermocouple, is provided which detects the outlet temperature To of the drying air. At the inlet 22 of the drum 16 another temperature sensor, for example a thermocouple, is provided which detects the inlet temperature Ti of the drying air. At the outlet of the condenser 32 a temperature sensor is provided which detects the refrigerant temperature Tr at this position. Inside the drum, electrodes may be present as well to determine the degree of humidity Hum of the laundry when it contacts the electrodes, for example by means of a resistivity measurement.

(18) FIG. 3 is a block diagram of components of the dryer 2 that interact for enabling a control unit 60 to control the drying operations or programs. The control unit 60 has a memory 62 in which program parameters and look-up tables are stored such that the control unit, by retrieving corresponding data from the memory 62, can control different basic drying programs preferably under conditions as set by the user via option selectors at the control panel 12. The user can select a program cycle among a list of different program cycles. The selection can be performed by means of a selector 13 in the panel 12. Alternatively, the program cycle can be selected via smartphone 100. Such user-settable options are for example: the type of drying cycle (cotton, delicate, outdoor, etc.), the final drying degree, the load of the laundry loaded by the user and inputted by him/her, the type of laundry, the duration of drying, an energy option, etc.

(19) In the memory 62 a database is present in which to each of a plurality of commands which can be sent from the first or the second interface a status is associated. Further, to each status a plurality of set parameters identifying the status is associated as well.

(20) For example, a command “pause” can be sent from the first or the second interface. The command “pause” identifies the status “interruption of the drying program” and it is defined by the following parameters (OP_2): Heat pump switched off. Process fan switched off. Drum stopped (not rotating). Optionally, the fan of the compressor may be switched on or off depending of the cycle and/or the temperature

(21) Further, to each command, a first and a second working routine are associated. The first routine is associated to the command if the command is sent via the first interface (smartphone 100), and the second working routine is associated to the same command if the command is sent via the second interface (control panel 12).

(22) For example, to the command “pause”, the following working routines are associated:

(23) First working routine: cooling phase (i.e. a plurality of parameters that implies the performance of a cooling phase);

(24) Second working routine: zero (no parameter is set, therefore, no parameter is modified from the setting given by the drying cycle).

(25) With now reference to FIG. 5, the dryer 2 is switched on in step S0 and a drying cycle is selected among those selectable by the first or second interface S1.

(26) In any selected drying cycle, the control unit 60 sends control signals to a drum motor inverter 64 and may receive operation parameters therefrom. The drum motor inverter 64 supplies the power to the motor 30 driving the drum 16 and the drying air fan 28. The control unit 60 may send control signals to a compressor motor inverter 66 and may receive operation parameters therefrom. The compressor motor inverter 66 powers a compressor motor 67 for driving the compressor 36. Further, the control unit 60 may control the draining pump 50, a motor 68 for driving the compressor cooling air fan 42 and optionally, if a separate motor 70 is provided for the drying air fan 28, the drying air fan motor 70. The command signals sent by the control unit 60 depend on the specific settings of the specific program (drying cycle) selected.

(27) The settings of the drying cycle of the selected programs are stored in the memory 62 and they may relate to one or more of: a frequency of the reversion of rotations of the drum 16 during the drying cycle, a speed of the process or drying air fan 28, the speed of the drum 16, the heat pump operation parameters.

(28) The selected drying cycle starts, S2. Preferably, during the drying cycle, the control unit 60 monitors not only the signals coming from the motor 30 or its inverter, the compressor cooling fan 42, the compressor motor inverter, the process air fan 28, etc., but also it preferably further monitors the signals coming from one or more sensors, for example it may receive the signals from the sensors for the refrigerant temperature Tr, or for the inlet temperature Ti of the drying air, or for the outlet temperature To of the drying air, or the conductivity measurements Hum made by the electrodes in the drum 16, or the level of water in the condensate collector 48 and/or the temporal gradient of a level of water removed from the outdoor textile to be dried and collected can be measured as well, or relative to the number of activations of the draining pump 50 of the condensate collector 48.

(29) A command is sent via the first 100 or the second interface 12 to the control unit 60. The command may be a “pause command”, and it is received by the control unit S3. In the control unit 60, in particular in the memory 62, the status connected to the command is retrieved and it is determined whether the command has been sent via the first or the second interface, S4.

(30) If the command “pause” has been sent via the smartphone 100, the instructions relating to the command, i.e. the operational parameters set by the status, are retrieved from memory 62, S5. The first working routine is a cooling phase S6. Therefore, the operational parameters set by the working routine and the operational parameters set by the status are both fulfilled at the end of the first working routine.

(31) At the end of the cooling phase, the set operational parameters determined by the command “pause” are fulfilled. The cooling phase terminates when the temperature of the laundry is below 55° C., S7, or after a predetermined operation time. After the end of the cooling phase, the laundry dryer reaches the status of “pause” and waits for an additional command, for example a resumption command S8. If a resumption command is received, the drying cycle resumes and, if no other command “pause” is given, the cycle prosecute until it ends. To avoid the appliance to remain paused indefinitely, it can be provided that the drying cycle ends after a predetermined “pause” time is elapsed (S12). Alternatively, the cooling phase ends when a new command, like a cycle resuming command, is received while the cooling phase is operating (see the next embodiment of FIG. 6).

(32) In case the command “pause” has been sent via the control panel 12, the instructions relating to the command, i.e. the operational parameters defining the status, are retrieved from memory 62, S9, and the second working routine does not add any new value to the parameters. Therefore, substantially “immediately”, the set operational parameters determined by the command “pause” are fulfilled (S10). The “pause” status terminates if an additional command is received, S11. In that case the given command is performed. To avoid the appliance to remain paused indefinitely, it can be provided that the drying cycle ends after a predetermined “pause” time is elapsed.

(33) The embodiment depicted in FIG. 6 is similar to that of FIG. 5, however a cycle “resuming” command, inputted either from the first or the second interface, is received by the control unit 60. Therefore, the drying cycle is resumed.

(34) In FIG. 6, only the portion of the flow diagram after the beginning of the first and/or second working routine is shown, the remaining of the flow diagram being identical to that of FIG. 5.

(35) In this case, a resumption command may be received and this is checked in phase S8. In case the cycle resumption command is received, then the drying cycle starts again S13.

(36) For example, the drying cycle may start again from the beginning, using as starting values the actual condition of the laundry, for example its humidity value. Preferably, the drying cycle remains the one selected from the beginning by the user, that is, for example the type of fabric indication and the desired level of humidity at the end of the cycle. The cycle ends as usual depending on the level of humidity of the laundry, that is, if the humidity level is below a certain threshold, then the cycles ends S11.

(37) Alternatively, in a drying cycle which has a fixed duration, which is a cycle that terminates depending not on the humidity of the laundry but only on a given elapsed time, the remaining drying cycle duration after the “resumption command” has been sent preferably depends on the moment in time at which the pause command has been sent, and also on the moment in time at which the resumption command has been sent. For example, if the pause command has been sent substantially at the beginning of the drying cycle, substantially no drying has been performed, thus the drying duration after resumption is preferably substantially the full drying cycle duration. Preferably, if the pause command has been sent substantially at the end of the drying cycle, after resumption only a relatively small amount of time is needed to complete the drying. Preferably, if the resumption command is sent shortly after the pause one, substantially no changes to the total duration of the cycle are made.

(38) In case such a resumption command is not received, the first or second working routine terminates as described according to the embodiment depicted in FIG. 5.