Method for controlling washing machine

Abstract

A method for controlling a washing machine, according to an embodiment of the present invention, is a method for controlling a washing machine comprising: a washing tub which uses carbon dioxide as a washing solvent, and which accommodates laundry; a compressor for compressing gaseous carbon dioxide; a distillation tank in which liquid carbon dioxide and gaseous carbon dioxide are present together; and a washing flow path for connecting the washing tub, the compressor and the distillation tub. A reset process for discharging carbon dioxide inside the washing tub is operated when an abnormal situation occurs such that the operation of the washing machine stops, wherein the reset process includes the steps of: sensing the internal pressure of the washing tub; discharging the liquid carbon dioxide by determining that the internal pressure of the washing tub is higher than a first set pressure; and, when discharging of the liquid carbon dioxide is complete, recovering, to the distillation tank, the gaseous carbon dioxide inside the washing tub until the internal pressure of the washing tub reaches the first set pressure.

Description

How to control a washing machine

[0001] The present invention relates to a control method for a washing machine that performs washing using carbon dioxide as a solvent instead of water.

[0002] In the case of washing machines that use carbon dioxide as a solvent for washing, the inside of the washing tub is maintained under high pressure during the washing process, so if an abnormality occurs during operation, the washing machine stops operating and an alarm sounds.

[0003] And, since you cannot know what state the washing machine is in when it stops running, for safety, you should call for service or manually discharge the carbon dioxide through the exhaust duct.

[0004] Abnormalities that occur during operation can include a sudden interruption of operation due to a malfunction of the washing machine itself or a power outage. If an abnormality occurs during washing, laundry inside the drum cannot be removed freely, and there is the risk of having to wait for a repairman to arrive at a service center or manually vent the carbon dioxide gas.

[0005] Because it's impossible to determine which cycle the washing machine stopped at when the machine is stopped, the carbon dioxide inside the drum must be exhausted and discarded, regardless of the internal condition. This makes carbon dioxide recovery impossible, requiring disposal and replenishment, which in turn increases costs.

[0006] Prior art: Korean Patent Publication No. 10-2023-0107498 (July 17, 2023)

[0007] The present invention is proposed to improve the above problems.

[0008] In order to achieve the above object, a control method of a washing machine according to an embodiment of the present invention is a control method of a washing machine that uses carbon dioxide as a washing solvent and includes a washing tub for accommodating laundry; a compressor for compressing gaseous carbon dioxide; a distillation tank in which liquid carbon dioxide and gaseous carbon dioxide coexist; and a washing passage connecting the washing tub, the compressor, and the distillation tank, wherein when an abnormal situation occurs and the operation of the washing machine is stopped, a reset process for discharging carbon dioxide inside the washing tub is started, and the reset process includes a step of detecting pressure inside the washing tub; a step of discharging liquid carbon dioxide when the pressure inside the washing tub is determined to be higher than a first set pressure; and a step of returning gaseous carbon dioxide inside the washing tub to the distillation tank when the discharge of the liquid carbon dioxide is completed until the pressure inside the washing tub reaches the first set pressure.

[0009] The above-mentioned abnormal situation includes at least one of a power outage situation or a breakdown situation of the washing machine, and the reset process is characterized in that it is performed at a time when power is re-supplied after the power outage is lifted or at a time when an alarm signal notifying a breakdown of the washing machine is generated.

[0010] The above first set pressure is characterized by being a minimum suction pressure that satisfies the allowable compression ratio of the compressor.

[0011] The above minimum suction pressure is characterized by being 2.5 bar.

[0012] While the gaseous carbon dioxide inside the washing tank is recovered to the distillation tank, when the internal pressure of the washing tank drops to the first set pressure, the process of recovering the gaseous carbon dioxide is terminated, and the gaseous carbon dioxide remaining inside the washing tank is discharged into the atmosphere.

[0013] When the internal pressure of the washing tank reaches the second set pressure, the reset process is terminated, and the second set pressure is characterized in that it is lower than the first set pressure.

[0014] If it is determined that the pressure inside the washing tub detected immediately after the reset process is started is not higher than the first set pressure, a process of exhausting the gaseous carbon dioxide remaining inside the washing tub into the atmosphere is immediately performed, and if the internal pressure of the washing tub reaches the second set pressure, the reset process is terminated.

[0015] While the gaseous carbon dioxide inside the washing tank is recovered to the distillation tank, when the internal pressure of the washing tank drops to the first set pressure, the gaseous carbon dioxide inside the washing tank is naturally recovered to the storage tank through a natural recovery path connecting the washing tank and the storage tank.

[0016] The above natural recovery process is characterized in that it is performed until the internal pressure of the washing tank is maintained constant.

[0017] When the internal pressure of the washing tub maintained at a constant level is higher than the second set pressure, the gaseous carbon dioxide inside the washing tub is exhausted into the atmosphere, and when the internal pressure of the washing tub reaches the second set pressure, the reset process is terminated, and the second set pressure is characterized in that it is lower than the first set pressure.

[0018] When the internal pressure of the washing tub maintained at a constant level is lower than the second set pressure, a ventilation hole provided on one side of the washing tub is opened, and when the internal pressure of the washing tub reaches the second set pressure, the reset process is terminated, and the second set pressure is characterized in that it is lower than the first set pressure.

[0019] If the internal pressure of the washing tank maintained at a constant level is higher than the second set pressure, the gaseous carbon dioxide inside the washing tank is forcibly recovered to the storage tank through a forced recovery path connecting the washing tank, the compressor, and the storage tank, and the second set pressure is characterized in that it is lower than the first set pressure.

[0020] The above-mentioned forced recovery process is characterized in that it is performed until the pressure inside the washing tank reaches the second set pressure, and the reset process is terminated.

[0021] While the gaseous carbon dioxide inside the washing tank is recovered to the distillation tank, when the internal pressure of the washing tank drops to the first set pressure, the gaseous carbon dioxide inside the washing tank is forcibly recovered to the storage tank through a forced recovery path connecting the washing tank, the compressor, and the storage tank.

[0022] The above forced recovery process is performed until the pressure inside the washing tank reaches a second set pressure, and the reset process is terminated, characterized in that the second set pressure is lower than the first set pressure.

[0023] The second set pressure is characterized in that it is atmospheric pressure.

[0024] According to a control method of a washing machine according to an embodiment of the present invention, when an abnormal situation occurs during operation and the operation of the washing machine is stopped, a reset process is operated to quickly exhaust carbon dioxide inside the washing tub, thereby having the advantage of allowing laundry inside the washing tub to be safely taken out.

[0025] In addition, when the washing machine is stopped from running, either carbon dioxide recovery or emission is automatically performed depending on the pressure in the washing tub, thereby minimizing unnecessary consumption of carbon dioxide.

[0026] Figure 1 is a drawing showing the configuration of a washing machine to which a control method according to an embodiment of the present invention is applied.

[0027] Figures 2 to 8 are diagrams showing the flow of carbon dioxide throughout the entire washing process.

[0028] Figure 9 is a flowchart illustrating a reset process of a washing machine according to an embodiment of the present invention.

[0029] Figure 10 is a system diagram showing a method for recovering gaseous carbon dioxide according to another embodiment of the present invention.

[0030] Figure 11 is a flowchart showing a reset process of a washing machine according to another embodiment of the present invention.

[0031] Figure 12 is a system diagram showing a method for recovering gaseous carbon dioxide according to another embodiment of the present invention.

[0032] Figure 13 is a flowchart illustrating a reset process of a washing machine according to another embodiment of the present invention.

[0033] Figure 14 is a flowchart illustrating a reset process of a washing machine according to another embodiment of the present invention.

[0034] Hereinafter, a method for controlling a washing machine according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0035] Figure 1 is a drawing showing the configuration of a washing machine to which a control method according to an embodiment of the present invention is applied.

[0036] Referring to FIG. 1, a washing machine (10) according to an embodiment of the present invention is a waterless washing machine that uses carbon dioxide instead of water for washing.

[0037] In detail, the washing machine (10) according to the present invention includes a washing tub (11) in which laundry is put and the entire washing process is performed, a vacuum pump (19) used to exhaust gas remaining in the washing tub (11) to create a vacuum state in the washing tub (11), a distillation tank (14) in which liquid carbon dioxide discharged from the washing tub (11) is stored, a compressor (13) operated to supply gaseous carbon dioxide to the washing tub (11) or to recover gaseous carbon dioxide inside the washing tub (11), and a cooler (15) that condenses gaseous carbon dioxide into liquid carbon dioxide in the process of recovering gaseous carbon dioxide inside the washing tub (11).

[0038] Inside the distillation tank (14), carbon dioxide in a gaseous state and carbon dioxide in a liquid state coexist. That is, the bottom of the distillation tank (14) is filled with carbon dioxide in a liquid state up to a predetermined level, and the internal space above it is filled with carbon dioxide in a gaseous state.

[0039] Additionally, the above components may be interconnected by pipes to form a circulation path. Each pipe or path constituting the circulation path is described in detail below with reference to the drawings.

[0040] Figures 2 to 8 are diagrams showing the flow of carbon dioxide throughout the entire washing process.

[0041] Referring to Fig. 2, a user opens the door of the washing tub (11), puts laundry in, closes the door, and presses the washing start button. Then, the vacuum pump (19) installed in the exhaust path (101) extending from one side of the washing tub (11) operates, completely removing air and moisture present inside the washing tub (11) to create a vacuum inside the washing tub (11).

[0042] Referring to Fig. 3, when the inside of the washing tank (11) becomes a vacuum pressure state, the so-called differential pressure supply passage (102) connecting the distillation tank (14) and the washing tank (11) is opened so that the gaseous carbon dioxide stored in the distillation tank (14) is supplied to the washing tank (11) by the pressure difference. Here, the supply of carbon dioxide by the differential pressure means that carbon dioxide is supplied by the phenomenon of naturally flowing from a chamber with a high pressure to a chamber with a low pressure. For reference, the internal pressure of the distillation tank (14) is maintained at approximately 30 bar before the supply of gaseous carbon dioxide begins.

[0043] In detail, as carbon dioxide moves from the distillation tank (14) to the washing tank (11) through the differential pressure supply path (102), the pressure inside the distillation tank (14) drops and the pressure inside the washing tank (11) increases. Then, when the pressure of the distillation tank (14) and the pressure of the washing tank (11) become equal to each other and a pressure equilibrium state is reached, the supply of gaseous carbon dioxide through the differential pressure supply path (102) is stopped.

[0044] Here, the supply of gaseous carbon dioxide may be interrupted either by the natural cessation of carbon dioxide movement due to pressure equilibrium, or by the artificial cessation of carbon dioxide movement by the closure of one or more on-off valves (not shown) installed in the differential pressure supply path (102). When the flow of gaseous carbon dioxide is interrupted, the supply of gaseous carbon dioxide may be considered complete.

[0045] Referring to Fig. 4, when the supply of gaseous carbon dioxide is completed, the gaseous carbon dioxide stored in the distillation tank (14) is changed into liquid carbon dioxide while passing through the distillation tank (14) and the cooler (15) through the liquid supply path (103) connecting the distillation tank (14), the compressor (13), and the washing tank (11), and then supplied to the washing tank (11).

[0046] In detail, the liquid supply path (103) may include a compressor suction path (1031) connecting the inlet of the distillation tank (14) and the compressor (13), a compressor discharge path (1032) connecting the outlet of the compressor (13) and the distillation tank (14), and a condensation path (1033) extending from an end of the compressor discharge path (1031) and passing through the interior of the distillation tank (14) and the cooler (15) and then extending to the washing tank (11).

[0047] When the compressor (13) operates, gaseous carbon dioxide inside the distillation tank (14) is sucked into the compressor (13) through the compressor suction passage (1031). Then, the sucked carbon dioxide is compressed at high temperature and high pressure while passing through the compressor (13) and then flows into the distillation tank (14) through the compressor discharge passage (1032).

[0048] In addition, the condensation path (1033) is extended while being immersed in the liquid carbon dioxide inside the distillation tank (14), so that heat is released from the high-temperature and high-pressure gaseous carbon dioxide flowing along the condensation path (1033) to the liquid carbon dioxide inside the distillation tank (14). Then, a portion of the liquid carbon dioxide inside the distillation tank (14) is vaporized, and the temperature and pressure of the carbon dioxide flowing along the condensation path (1033) drop. In addition, instead of the gaseous carbon dioxide being released along the compressor path (1031), a portion of the liquid carbon dioxide is vaporized through heat exchange with the condensation path (1033), so that the phenomenon of the gaseous carbon dioxide being completely depleted inside the distillation tank (14) does not occur.

[0049] Meanwhile, the condensation path (1033) passing through the distillation tank (14) extends to the washing tank (11) after passing through the cooler (15). Accordingly, the gaseous carbon dioxide flowing along the condensation path (1033) releases heat to the outside while passing through the cooler (15) and is completely condensed into liquid carbon dioxide, so that the liquid carbon dioxide is supplied to the washing tank (11) (see dotted arrow). Then, when the internal pressure of the distillation tank (14) drops to about 12 to 15 bar, the supply of the liquid carbon dioxide is stopped, and the washing process is performed.

[0050] Referring to FIG. 5, after the supply of gaseous carbon dioxide and liquid carbon dioxide is completed as shown in FIG. 4, a washing process is performed, and when the washing process is completed, a process of discharging contaminated liquid carbon dioxide in the washing tub (11) is performed.

[0051] In detail, the remaining liquid carbon dioxide after the completion of the washing process is discharged to the distillation tank (14) through the liquid discharge path (104) connecting the washing tank (11) and the distillation tank (14). At this time, in order to prevent the pressure inside the washing tank (11) from decreasing during the process of discharging the liquid carbon dioxide and delaying the discharge of the liquid carbon dioxide, a ventilation process is performed to supply gaseous carbon dioxide into the washing tank (11) simultaneously with the discharge of the liquid carbon dioxide.

[0052] In detail, the above-described ventilation process is performed through a ventilation path (105) connecting the distillation tank (14), the compressor, and the washing tank (11). The ventilation path (105) includes a suction-side ventilation path (1051) connecting the distillation tank (14) and the suction port of the compressor (13), and a discharge-side ventilation path (1052) connecting the discharge port of the compressor (13) and the washing tank (11).

[0053] In more detail, when the ventilation process starts, the gaseous carbon dioxide inside the distillation tank (14) is introduced into the compressor (13) through the suction-side ventilation path (1051) and supplied to the washing tank (11) through the discharge-side ventilation path (1052). As a result, even if the liquid carbon dioxide is discharged into the distillation tank (14), the phenomenon of the pressure inside the washing tank (11) decreasing does not occur. In addition, when the liquid carbon dioxide inside the washing tank (11) is completely discharged, the ventilation process is also stopped.

[0054] Referring to Fig. 6, when the discharge of contaminated liquid carbon dioxide is completed, the carbon dioxide that has been phase-changed into a liquid state through a process of compressing and condensing the gaseous carbon dioxide remaining in the distillation tank (14) is re-supplied to the washing tank (11) so that a rinsing process can be performed.

[0055] In detail, the process of supplying liquid carbon dioxide for rinsing is the same as the process of supplying liquid carbon dioxide described in Fig. 4, so a description thereof is omitted.

[0056] Referring to Fig. 7, when the rinsing process is completed, a process is performed to discharge the contaminated liquid carbon dioxide remaining in the washing tank (11) to the distillation tank (14), similar to the liquid carbon dioxide discharge process after the washing process.

[0057] In detail, a ventilation process is performed in which contaminated liquid carbon dioxide is discharged to the distillation tank (14) through the liquid discharge path (14) and gaseous carbon dioxide is supplied to the washing tank (11) through the ventilation path (105). Since the details thereof are the same as those described in Fig. 5, a duplicate description is omitted.

[0058] Referring to Fig. 8, when the discharge of contaminated liquid carbon dioxide is completed, a recovery process is performed to recover high-temperature, high-pressure gaseous carbon dioxide remaining inside the washing tank (11).

[0059] In detail, in order to recover the vaporous carbon dioxide, a recovery path (106) connecting the washing tank (11), the compressor (13), the distillation tank (14), and the cooler (15) is opened. The recovery path (106) includes a suction recovery path (1061) connecting the washing tank (11) and the suction port of the compressor (13), a discharge recovery path (1062) connecting the discharge port of the compressor (13) and the washing tank (11) and the distillation tank (14), and a condensation recovery path (1063) extending from the discharge recovery path (1062), passing through the distillation tank (14) and the cooler (15), and then being connected to the distillation tank (14) again.

[0060] When the recovery process begins, the gaseous carbon dioxide inside the washing tank (11) is exhausted through the suction recovery path (1061) and flows into the compressor (13). Then, the carbon dioxide exhausted through the suction recovery path (1061) is compressed at high temperature and high pressure while passing through the compressor (13) and then discharged through the discharge recovery path (1062).

[0061] The above discharge recovery path (1062) passes through the inside of the washing tub (11) and then extends to the distillation tank (14). Therefore, the high-temperature, high-pressure gaseous carbon dioxide discharged from the compressor (13) passes through the inside of the washing tub (11), but does not mix with the gaseous carbon dioxide inside the washing tub (11) and only releases heat into the inside of the washing tub (11). In this process, the temperature inside the washing tub (11) increases, thereby preventing the temperature inside the washing tub (11) from rapidly decreasing as the carbon dioxide escapes from the washing tub (11) to the outside. As a result, when the laundry is taken out after the end of washing, the temperature inside the washing tub is significantly lower than the outside temperature, so that the phenomenon of moisture condensing on the surface of the laundry when the laundry is taken out can be prevented.

[0062] Carbon dioxide, the temperature of which drops as it passes through the washing tank (11), exchanges heat with the liquid carbon dioxide inside the distillation tank (14) as it passes through the distillation tank (14), so that the temperature and pressure drop further, and some of the liquid carbon dioxide inside the distillation tank (14) vaporizes.

[0063] In addition, the carbon dioxide cooled while passing through the distillation tank (14) is condensed into liquid carbon dioxide while passing through the cooler (15) and then reintroduced into the distillation tank (14). As the recovery process progresses, the amount of gaseous carbon dioxide inside the washing tank (11) decreases, and the pressure inside the washing tank (11) gradually drops, and the level of liquid carbon dioxide recovered into the distillation tank (14) gradually increases.

[0064] And, when the pressure inside the washing tub (11) drops to the set pressure, the recovery process is terminated. Here, the pressure inside the washing tub (11) that determines whether the recovery process is terminated may be about 2.5 bar, but is not limited thereto. The set pressure is determined by the allowable compression ratio of the compressor (13). The compression ratio may be defined as discharge pressure / suction pressure, and when the compressor (13) is operated under conditions exceeding the allowable compression ratio, the reliability tolerance of the compressor (13) may be exceeded, which may result in damage to the compressor or deterioration of its performance.

[0065] For example, in the case of a compressor with an allowable compression ratio of 15, if the discharge pressure is 38 bar, the suction pressure cannot be lowered below 2.5 bar. Here, the suction pressure corresponds to the pressure inside the washing tub (11), and the discharge pressure corresponds to the pressure inside the storage tank (12). Therefore, when the pressure inside the washing tub (11) reaches 2.5 bar during the recovery process, the recovery process can no longer be performed. In this state, the recovery process is terminated, and the small amount of gaseous carbon dioxide remaining inside the washing tub (11) is discharged to the outside through the exhaust passage (101).

[0066] And, when the pressure inside the washing tub (11) becomes equal to the atmospheric pressure through the exhaust process, the entire washing process is completed, and the door of the washing tub (11) can be opened to take out the laundry.

[0067] It should be noted that the above-described flow paths may each form independent flow paths, or may share at least part or all of them with other flow paths to simplify the piping configuration. For example, the compressor suction flow path (1031) constituting the liquid supply flow path (103) is the same flow path as the suction-side ventilation flow path (1051) constituting the ventilation flow path (105), but the names of the flow paths may be defined differently depending on the process in which the carbon dioxide flow occurs. Of course, the liquid supply flow path (103) and the suction-side ventilation flow path (1051) may each form independent and separate flow paths.

[0068] Meanwhile, if a power outage occurs during washing or rinsing according to the process described above, or if a component of the washing machine (10) malfunctions, the washing process is immediately halted. In this state, the reset process according to the present invention is immediately executed, and this process is described in detail in the flowchart below.

[0069] Figure 9 is a flowchart illustrating a reset process of a washing machine according to an embodiment of the present invention.

[0070] Referring to Figure 9, at some point after the washing cycle begins, a power outage occurs or the washing machine malfunctions, causing the washing machine to stop operating and generate a warning signal. Then, when the power outage is resolved and power is restored, or when a warning signal is generated due to a malfunction, the reset process according to the present invention is immediately initiated.

[0071] When the above reset process is executed, the control unit of the washing machine (10) determines whether the internal pressure of the washing tub (11) is higher than the first set pressure (S11). Here, the first set pressure means the minimum suction pressure that satisfies the allowable compression ratio of the compressor (11), specifically, the internal pressure of the washing tub (11), and may be, for example, 2.5 bar, but the set pressure value may vary depending on the type of compressor (13).

[0072] In detail, if the pressure of the washing tank (11) is determined to be higher than the first set pressure, the liquid carbon dioxide discharge process (S12) described in FIG. 5 is performed first, and when the discharge of the liquid carbon dioxide is completed (S13), the gaseous carbon dioxide recovery process described in FIG. 8 is performed (S14).

[0073] Here, the point in time when the discharge of the liquid carbon dioxide is completed can be determined by various methods. For example, it can be determined by any one of the following: the point in time when the water level inside the distillation tank (14) stops increasing, the point in time when the pressure inside the distillation tank (14) stops changing, the point in time when a set time has elapsed from the point in time when the liquid carbon dioxide is discharged, or the point in time when the rotation of the flow meter (not shown) installed in the liquid discharge path (104) stops. It should be noted that various other methods can be applied.

[0074] And, in the process of recovering the vaporous carbon dioxide, if the pressure in the washing tank falls below the first set pressure, the process of exhausting the vaporous carbon dioxide through the exhaust path (101) (S15) is performed, and the exhaust process is performed until the pressure in the washing tank (11) falls to the second set pressure (S16). The second set pressure may mean atmospheric pressure.

[0075] Meanwhile, if the pressure of the washing tub (11) is determined to be lower than the first set pressure at the time the reset process is executed, the carbon dioxide exhaust process (S15) is performed immediately without a recovery process. Here, if the pressure of the washing tub (11) is lower than the first set pressure, since no liquid carbon dioxide exists inside the washing tub (11), the liquid carbon dioxide exhaust process may not be performed separately.

[0076] In this way, if the pressure in the washing machine is determined to be higher than the first set pressure at the time of starting the reset process, the carbon dioxide is not immediately exhausted, but the recovery process is performed until the pressure drops to the first set pressure, thereby minimizing unnecessary consumption of carbon dioxide.

[0077] Figure 10 is a system diagram showing a method for recovering gaseous carbon dioxide according to another embodiment of the present invention.

[0078] Referring to FIG. 10, in addition to the process of liquefying and recovering gaseous carbon dioxide to the distillation tank until the pressure inside the washing tank drops to the first set pressure after the discharge of liquid carbon dioxide is completed among the steps of the control method described in FIG. 9, it is also possible to store gaseous carbon dioxide in a separate storage tank (16) without immediately discharging it.

[0079] In detail, the gaseous carbon dioxide is recovered and liquefied until the pressure inside the washing tank drops to the first set pressure and is recovered in the distillation tank (14). Then, when the pressure inside the washing tank reaches the first set pressure, the gaseous carbon dioxide remaining inside the washing tank (11) is recovered in a separate storage tank (16).

[0080] For example, the path directly connecting the washing tub (11) and a separate storage tank (16) may be opened so that the gaseous carbon dioxide remaining inside the washing tub (11) is recovered to the storage tank (16) by the pressure difference. Here, the path directly connecting the washing tub (11) and the storage tank (16) may be defined as a "natural recovery path."

[0081] Then, we can further minimize carbon dioxide consumption by further reducing the amount of atmospheric carbon dioxide released into the atmosphere.

[0082] Figure 11 is a flowchart showing a reset process of a washing machine according to another embodiment of the present invention.

[0083] Referring to FIGS. 10 and 11, when a problem occurs in the washing machine or a power outage occurs and a reset process is initiated, the same steps (S21 to S24) as those performed in steps S11 to S14 of FIG. 9 are performed. That is, when the pressure in the washing tank is higher than the first set pressure that satisfies the compression ratio of the compressor (13), the process of discharging liquid carbon dioxide and liquefying gaseous carbon dioxide inside the washing tank and recovering it to the distillation tank (14) is sequentially performed.

[0084] And, when the washing tank pressure reaches the first set pressure, instead of exhausting the gaseous carbon dioxide into the atmosphere, the gaseous carbon dioxide is naturally recovered by the pressure difference to the washing tank (11) through the natural recovery path (107) (S25).

[0085] And, while the gaseous carbon dioxide is naturally recovered into the storage tank (16), it is determined whether there is a change in the pressure of the washing tub (S16). If it is determined that the current detected pressure of the washing tub is lower than the previous detected pressure, the natural recovery process is allowed to continue, and if it is determined that the current detected pressure and the previous detected pressure are the same, it is determined whether the pressure of the washing tub is higher than a second set pressure, for example, atmospheric pressure (S27).

[0086] The absence of change in the pressure inside the washing tub means that the washing tub (11) and the storage tank (16) have reached equilibrium pressure and no longer move gaseous carbon dioxide. Therefore, when the pressure in the washing tub is higher than atmospheric pressure, the carbon dioxide remaining inside the washing tub is exhausted into the atmosphere through the vacuum pump (19) (S28).

[0087] Conversely, if the constant pressure in the washing machine tub is determined to be no higher than atmospheric pressure, a determination is made as to whether the detected pressure is equal to atmospheric pressure (S29). If the detected pressure is determined to be equal to atmospheric pressure, the user is permitted to open the washing machine door, thus completing the reset process.

[0088] On the other hand, if it is determined that the pressure inside the washing tub is lower than the atmospheric pressure, the vent hole (111) provided on one side of the washing tub (11) may be opened (S30) so that the pressure inside the washing tub becomes equal to the atmospheric pressure, and then the reset process may be terminated. The vent hole (111) may be opened and closed automatically by a solenoid valve or the like, or may be opened and closed manually by a user.

[0089] Meanwhile, the process of recovering gaseous carbon dioxide into the distillation tank (14) can be defined as a primary recovery process, and the process of recovering gaseous carbon dioxide into the storage tank (16) can be defined as a secondary recovery process.

[0090] Figure 12 is a system diagram showing a method for recovering gaseous carbon dioxide according to another embodiment of the present invention.

[0091] Referring to Fig. 12, as described in Figs. 10 and 11, the system according to the present embodiment is also characterized by having a separate storage tank (16) to recover gaseous carbon dioxide. However, unlike the natural recovery method described in Fig. 10, there is a difference in that gaseous carbon dioxide is forcibly recovered using the compressor (13).

[0092] In detail, the gaseous dinitrogen inside the washing tank (11) can be recovered to the storage tank (16) through a recovery path, a so-called “forced recovery path”, which connects the washing tank (11), the compressor (13), and the storage tank (16).

[0093] The forced recovery process of gaseous carbon dioxide using the compressor (13) may be performed subsequent to the natural recovery process described in FIGS. 10 and 11, or may be performed independently of the natural recovery process. This will be described in more detail below with reference to the flowchart.

[0094] Figure 13 is a flowchart illustrating a reset process of a washing machine according to another embodiment of the present invention.

[0095] Referring to FIGS. 12 and 13, when the reset process operation conditions are satisfied as described in FIGS. 9 and 11, the control unit of the washing machine (10) sequentially performs the gaseous carbon dioxide recovery steps (S31 to S34) starting from the step of determining whether the internal pressure of the washing tub (11) is higher than the first set pressure.

[0096] And, if it is determined that the pressure of the washing tub (11) is not higher than the first set pressure, the compressor (13) is operated so that the gaseous carbon dioxide inside the washing tub (11) is forcibly recovered to the storage tank (16) along the forced recovery path (108) (S35). And, the forced recovery process is continuously performed until the washing tub pressure drops to the second set pressure, which is the atmospheric pressure (S36). And, when the washing tub pressure reaches the atmospheric pressure, the reset process is terminated because the user can directly open the washing tub door.

[0097] Figure 14 is a flowchart illustrating a reset process of a washing machine according to another embodiment of the present invention.

[0098] Referring to FIG. 14, the reset process of the washing machine according to the present embodiment is, as described in FIGS. 9, 11, and 13, when the reset process operation conditions are satisfied, the control unit of the washing machine (10) sequentially performs the gaseous carbon dioxide recovery step (S41 to S44) starting from the step of determining whether the internal pressure of the washing tub (11) is higher than the first set pressure.

[0099] And, if it is determined that the pressure of the washing tank (11) is not higher than the first set pressure, a secondary recovery process is performed to recover the gaseous carbon dioxide inside the washing tank (11) to the storage tank (16), as described in FIG. 11.

[0100] However, the secondary recovery process is different from the secondary recovery process described in FIG. 11 or FIG. 13 in that the natural recovery process and the forced recovery process are performed sequentially.

[0101] In detail, if it is determined that the pressure of the washing tank (11) is not higher than the first set pressure while the first recovery process is being performed, a natural recovery process is first performed in which the gaseous carbon dioxide is recovered to the storage tank (16) through the natural recovery path (107) (S45).

[0102] And, while the above natural recovery process is being performed, it is determined whether there is a change in the pressure inside the washing tub (S46). If it is determined that the current detected pressure inside the washing tub is lower than the previous detected pressure, the natural recovery process is allowed to continue. On the other hand, if it is determined that the current detected pressure and the previous detected pressure are the same, it means that carbon dioxide is not moving from the washing tub (11) to the storage tank (16), and therefore the natural recovery process is terminated.

[0103] And, it is determined whether the internal pressure of the washing tub, which is maintained at a constant level, is higher than the second set pressure, which is the atmospheric pressure (S47). And, if it is determined that the washing tub pressure is higher than the atmospheric pressure, a process of forcibly recovering the gaseous carbon dioxide is performed (S48). That is, the compressor (13) operates, the forced recovery path (108) is opened, and the gaseous carbon dioxide remaining inside the washing tub (11) is forcibly recovered to the storage tank (16).

[0104] And, if it is determined that the pressure of the washing tub detected during the forced recovery process has reached atmospheric pressure, the reset process is terminated since the user can open the door of the washing tub. At this time, the gaseous carbon dioxide remaining inside the washing tub (11) is discharged into the atmosphere by opening the washing tub door.

[0105] Meanwhile, even if the internal pressure of the washing tub, which is maintained at a constant level, is determined to be equal to the atmospheric pressure, the reset process is terminated because the user can open the door of the washing tub.

[0106] On the other hand, if the internal pressure of the washing tub, which is maintained at a constant level, is determined to be lower than atmospheric pressure, the user is prevented from opening the door of the washing tub. In this case, the ventilation hole (111) is opened (S51) so that the internal pressure of the washing tub becomes equal to atmospheric pressure, and then the reset process is terminated.

[0107]

Claims

1. A method for controlling a washing machine using carbon dioxide as a washing solvent, comprising: a washing tank containing laundry; a compressor for compressing gaseous carbon dioxide; a distillation tank in which liquid carbon dioxide and gaseous carbon dioxide coexist; and a washing path connecting the washing tank, the compressor, and the distillation tank. When an abnormal situation occurs and the operation of the washing machine is stopped, a reset process that discharges carbon dioxide inside the washing tub is started. The above reset process is, A step in which the pressure inside the washing tank is detected; A step in which the pressure inside the washing tank is determined to be higher than the first set pressure, and liquid carbon dioxide is discharged; and A control method for a washing machine, comprising a step of recovering gaseous carbon dioxide inside the washing tank to the distillation tank until the pressure inside the washing tank reaches the first set pressure when the liquid carbon dioxide discharge is completed.

2. In paragraph 1, The above abnormal situation includes at least one of a power outage situation or a breakdown situation of the washing machine, The above reset process is, A method for controlling a washing machine, characterized in that it is performed when power is restored after a power outage or when an alarm signal indicating a breakdown of the washing machine is generated.

3. In paragraph 1, The above first set pressure is, A control method for a washing machine, characterized in that the minimum suction pressure satisfies the allowable compression ratio of the compressor.

4. In paragraph 3, A control method for a washing machine, characterized in that the minimum suction pressure is 2.5 bar.

5. In paragraph 3, A control method for a washing machine, characterized in that when the internal pressure of the washing tank drops to the first set pressure while the gaseous carbon dioxide inside the washing tank is recovered to the distillation tank, the recovery process of the gaseous carbon dioxide is terminated, and the gaseous carbon dioxide remaining inside the washing tank is exhausted into the atmosphere.

6. In paragraph 5, When the internal pressure of the washing machine reaches the second set pressure, the reset process ends, A control method for a washing machine, characterized in that the second set pressure is lower than the first set pressure.

7. In paragraph 6, If it is determined that the pressure inside the washing tub detected immediately after the above reset process is operated is not higher than the first set pressure, the process of exhausting the gaseous carbon dioxide remaining inside the washing tub into the atmosphere is performed immediately. A control method for a washing machine, characterized in that the reset process is terminated when the internal pressure of the washing tub reaches the second set pressure.

8. In paragraph 3, A control method for a washing machine, characterized in that, while the gaseous carbon dioxide inside the washing tank is recovered to the distillation tank, when the internal pressure of the washing tank drops to the first set pressure, the gaseous carbon dioxide inside the washing tank is naturally recovered to the storage tank through a natural recovery path connecting the washing tank and the storage tank.

9. In paragraph 8, A control method for a washing machine, characterized in that the above natural recovery process is performed until the internal pressure of the washing tub is maintained constant.

10. In paragraph 9, If the internal pressure of the washing tank maintained at a constant level is higher than the second set pressure, the gaseous carbon dioxide inside the washing tank is exhausted into the atmosphere, When the internal pressure of the washing machine reaches the second set pressure, the reset process is terminated. A control method for a washing machine, characterized in that the second set pressure is lower than the first set pressure.

11. In paragraph 9, When the internal pressure of the washing tub maintained at a constant level is lower than the second set pressure, the ventilation hole provided on one side of the washing tub is opened, When the internal pressure of the washing machine reaches the second set pressure, the reset process is terminated. A control method for a washing machine, characterized in that the second set pressure is lower than the first set pressure.

12. In paragraph 9, If the internal pressure of the washing tank maintained at a constant level is higher than the second set pressure, the gaseous carbon dioxide inside the washing tank is forcibly recovered to the storage tank through a forced recovery path connecting the washing tank, the compressor, and the storage tank. A control method for a washing machine, characterized in that the second set pressure is lower than the first set pressure.

13. In paragraph 12, The above mandatory recovery process is, A control method for a washing machine, characterized in that the reset process is performed until the pressure inside the washing tub reaches the second set pressure, and the reset process is terminated.

14. In paragraph 3, A control method for a washing machine, characterized in that, while the gaseous carbon dioxide inside the washing tank is recovered to the distillation tank, when the internal pressure of the washing tank drops to the first set pressure, the gaseous carbon dioxide inside the washing tank is forcibly recovered to the storage tank through a forced recovery path connecting the washing tank, the compressor, and the storage tank.

15. In paragraph 14, The above mandatory recovery process is, The process is performed until the pressure inside the washing tank reaches the second set pressure, and the reset process is terminated. A control method for a washing machine, characterized in that the second set pressure is lower than the first set pressure.

16. In any one of paragraphs 6, 10 to 12, and 15, A control method for a washing machine, characterized in that the second set pressure is atmospheric pressure.

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