Washing machine and method for controlling same

Abstract

A washing machine according to an embodiment of the present invention comprises: a washing tub into which laundry is put: a distillation tub that is connected to the washing tub and supplies carbon dioxide to the washing tub or stores carbon dioxide recovered from the washing tub; a compressor that is connected to the washing tub and the distillation tub and compresses gaseous carbon dioxide stored in the washing tub or the distillation tub; a condensing cooler for liquefying the gaseous carbon dioxide that passes through the compressor; a gas storage tank for storing the gaseous carbon dioxide recovered from the washing tub after washing is completed; and a washing flow path connecting the washing tub, the distillation tub, the compressor, the cooler, and the gas storage tank.

Description

Washing machine and its control method

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

[0002] A washing machine that uses carbon dioxide as a washing solvent is defined as a non-water washing machine. In such a non-water washing machine, carbon dioxide is used as a washing solvent while moving between a washing tank and a distillation tank, which are pressure vessels, and flows in a liquid or gaseous state depending on the washing cycle.

[0003] In conventional waterless washing machines, the carbon dioxide gas remaining inside the washing tub after the end of the wash cycle is not completely recovered, but is recovered only until the pressure inside the washing tub reaches a certain pressure (2 to 3 bar), and the remaining gas is released into the atmosphere by opening the exhaust valve.

[0004] During the gas recovery stage, the internal pressure of the washing machine cannot be reduced to atmospheric pressure due to reliability issues related to the compressor's compression ratio. Reducing the internal pressure to a pressure exceeding the compressor's compression ratio could cause the compressor's mechanical components to exceed their guaranteed reliability, potentially resulting in damage or functional degradation.

[0005] In this way, by releasing some of the residual gases remaining in the washing machine into the atmosphere, it has a negative impact on the global warming potential (GWP).

[0006] In addition, since some of the carbon dioxide gas must be discarded each time a wash is performed, there is a disadvantage in that the carbon dioxide must be replenished periodically.

[0007] Prior Art 1: Korean Patent Publication No. 10-2023-0109476 (July 20, 2023)

[0008] Prior Art 2: U.S. Patent Publication No. 5,822,818 (October 20, 1998)

[0009] The present invention is proposed to improve the above problems.

[0010] In order to achieve the above object, a washing device according to an embodiment of the present invention includes a washing tub into which laundry is put; a distillation tank connected to the washing tub and supplying carbon dioxide to the washing tub or storing carbon dioxide recovered from the washing tub; a compressor connected to the washing tub and the distillation tank and compressing gaseous carbon dioxide stored in the washing tub or the distillation tank; a condensing cooler that liquefies gaseous carbon dioxide passing through the compressor; a gas storage tank in which gaseous carbon dioxide recovered from the washing tub after washing is stored; and a washing passage connecting the washing tub, the distillation tank, the compressor, the cooler, and the gas storage tank.

[0011] The washing machine according to the present invention may further include a vacuum pump for evacuating the washing tank or the gas storage tank.

[0012] The above gas storage tank is characterized in that it is a container in which the carbon dioxide remaining after being first recovered from the washing tank to the distillation tank is secondarily recovered and stored.

[0013] After the washing process is completed, the carbon dioxide recovered and stored in the gas storage tank is characterized in that it is re-supplied into the washing tank, which is in a vacuum state, during the next washing process.

[0014] The above washing machine path may include a washing machine vacuum path that connects the washing machine and the vacuum pump in the washing machine vacuum process.

[0015] The above laundry path includes a primary gas supply path that connects the gas storage tank and the laundry tank in a vacuum state in the primary gas supply process, and the carbon dioxide stored in the gas storage tank is naturally supplied by a pressure difference between the gas storage tank and the laundry tank.

[0016] The above washing passage includes a secondary gas supply passage connecting the distillation tank and the washing tank in a secondary gas supply process, and the carbon dioxide stored in the distillation tank is naturally supplied by the pressure difference between the washing tank and the distillation tank until the pressure inside the washing tank increases to a set pressure.

[0017] The above washing machine may include a storage tank vacuuming path connecting the storage tank and the vacuum pump in the storage tank vacuuming process.

[0018] The above washing machine comprises a liquid supply path that connects the distillation tank, the compressor, the cooler, and the washing tank in the liquid supply process, and the gaseous carbon dioxide stored in the distillation tank is liquefied while passing through the cooler and then supplied to the washing tank.

[0019] The above liquid supply path connects the outlet of the compressor and the inlet of the cooler, and includes a condensation path passing through the interior of the distillation tank, and carbon dioxide flowing along the condensation path is first condensed while exchanging heat with liquid carbon dioxide stored in the distillation tank, and carbon dioxide passing through the condensation path is secondarily condensed while passing through the cooler.

[0020] The above washing path includes a drain path connecting the washing tank and the distillation tank in a drain operation, and is characterized in that after the washing operation or the rinsing operation is completed, the liquid carbon dioxide inside the washing tank is discharged to the distillation tank.

[0021] The washing passage includes a first gas recovery passage connecting the washing tank, the compressor, the distillation tank, and the cooler in a first gas recovery process, and carbon dioxide inside the washing tank is sucked into the compressor, and carbon dioxide discharged from the compressor is first condensed while exchanging heat with carbon dioxide remaining inside the washing tank while passing through a heat dissipation passage penetrating the inside of the washing tank, and carbon dioxide passing through the heat dissipation passage is secondarily condensed while exchanging heat with liquid carbon dioxide inside the distillation tank while passing through a condensation passage penetrating the inside of the distillation tank, and carbon dioxide passing through the condensation passage is liquefied while passing through the cooler and then recovered to the distillation tank.

[0022] The above laundry path may include a secondary gas recovery path connecting the laundry tank and the storage tank in a secondary gas recovery process.

[0023] The secondary gas recovery path includes a natural recovery path that directly connects the washing tank and the gas storage tank in a vacuum state, and the gaseous carbon dioxide remaining in the washing tank is naturally recovered by the pressure difference between the washing tank and the gas storage tank.

[0024] The secondary gas recovery path includes a forced recovery path connecting the washing tub, the compressor, and the gas storage tank, and the gaseous carbon dioxide remaining in the washing tub after the natural recovery is forcibly recovered from the washing tub to the gas storage tank by the compressor.

[0025] The present invention further comprises a mixer disposed on the primary gas supply path; a detergent container connected to the mixer; and an additive container connected to the mixer, wherein carbon dioxide supplied from the gas storage tank, detergent supplied from the detergent container, and additive supplied from the additive container are mixed in the mixer and then supplied to the washing tank.

[0026] A control method of a washing machine according to an embodiment of the present invention is a method for performing a washing process when laundry is placed in a washing tub and a washing tub door is closed, the washing process including a washing tub vacuumization process in which the inside of the washing tub is lowered into a vacuum state; a gas supply process in which gaseous carbon dioxide is supplied into the washing tub; a liquid supply process in which liquid carbon dioxide is supplied into the washing tub; a washing process; a rinsing process; a drain process in which contaminated liquid carbon dioxide is drained; a first gas recovery process in which gaseous carbon dioxide inside the washing tub is recovered to a distillation tank; and a second gas recovery process in which gaseous carbon dioxide inside the washing tub is recovered to a gas storage tank.

[0027] The above gas supply process includes at least one of a first gas supply process in which gaseous carbon dioxide recovered in the gas storage tank is naturally supplied to the washing tank by a pressure difference; and a second gas supply process in which gaseous carbon dioxide stored in the distillation tank is naturally supplied to the washing tank by a pressure difference.

[0028] When the first gas supply process is completed, a storage tank vacuuming process is performed to make the gas storage tank into a vacuum state, and one of the storage tank vacuuming process and the second gas supply process is performed before the other.

[0029] The above liquid supply process includes a first liquid supply process performed before the washing process; and a second liquid supply process performed before the rinsing process.

[0030] The above drain process includes a first drain process performed after the washing process; and a second drain process performed after the rinsing process.

[0031] The above first gas recovery process is characterized in that it ends when the internal pressure of the washing tank reaches a set pressure, and the set pressure is a pressure corresponding to the compression ratio of the compressor.

[0032] The above secondary gas recovery process includes a natural recovery process in which carbon dioxide remaining in the washing tank after the first gas recovery process is recovered to the gas storage tank by a pressure difference.

[0033] When the above natural recovery process starts, the natural recovery path connecting the washing tank and the gas storage tank is opened, and when the pressure inside the washing tank reaches a constant pressure state, the natural recovery path is closed.

[0034] In the above-mentioned equilibrium state, when the pressure inside the washing tub is higher than the atmospheric pressure, the gaseous carbon dioxide remaining inside the washing tub is exhausted into the atmosphere, when the pressure inside the washing tub is lower than the atmospheric pressure, the ventilation hole of the washing tub is opened, and when the pressure inside the washing tub is equal to the atmospheric pressure, the secondary gas recovery process is terminated.

[0035] The above secondary gas recovery process includes a forced recovery process in which carbon dioxide remaining in the washing tank after the first gas recovery process is forcibly recovered to the gas storage tank by a compressor.

[0036] When the above-mentioned forced recovery process starts, the compressor operates with the opening of the forced recovery path connecting the washing tank, the compressor, and the gas storage tank, and the above-mentioned forced recovery process is characterized in that it is performed until the pressure inside the washing tank reaches atmospheric pressure.

[0037] The above secondary gas recovery process includes a natural recovery process in which carbon dioxide remaining in the washing tub after the first gas recovery process is naturally recovered into the gas storage tank, and a forced recovery process in which carbon dioxide remaining in the washing tub after the natural recovery process is forcibly recovered into the gas storage tank by a compressor.

[0038] When the above natural recovery process starts, the natural recovery path connecting the washing tub and the gas storage tank is opened, and when the pressure inside the washing tub reaches a constant pressure state, the natural recovery path is closed, and when the pressure inside the washing tub is higher than the atmospheric pressure in the pressure state, the forced recovery process is performed, and when the pressure inside the washing tub is lower than the atmospheric pressure, the ventilation hole of the washing tub is opened, and when the pressure inside the washing tub is equal to the atmospheric pressure, the secondary gas recovery process is terminated.

[0039] When the above-mentioned forced recovery process starts, the compressor operates with the opening of the forced recovery path connecting the washing tank, the compressor, and the gas storage tank, and the above-mentioned forced recovery process is characterized in that it is performed until the pressure inside the washing tank reaches atmospheric pressure.

[0040] According to the embodiment of the present invention having the above configuration, the washing device and its control method have the following effects.

[0041] First, since all carbon dioxide gas remaining in the washing tub after the wash is finished can be recovered into the gas storage tank, there is no carbon dioxide gas wasted, so there is no impact on the global warming index, which has the advantage of enabling the implementation of an eco-friendly product.

[0042] Second, since it can be recycled entirely without wasting carbon dioxide gas, there is no need to periodically replenish carbon dioxide, which has the advantage of reducing the cost of using detergent.

[0043] Third, by forcibly recovering carbon dioxide into a storage tank using a compressor, the recovered carbon dioxide can be liquefied and stored, which allows for a reduction in the size of the storage tank, which has the advantage of making the washing machine more compact.

[0044] Figure 1 is a configuration diagram of a washing device according to an embodiment of the present invention.

[0045] Figure 2 is a flowchart showing the entire washing process performed in a washing device according to an embodiment of the present invention.

[0046] Figure 3 is a drawing showing the flow of air in the washing machine vacuum process.

[0047] Figure 4 is a drawing showing the flow of washing solvent in the first gas supply process.

[0048] Figure 5 is a drawing showing the flow of washing solvent in the secondary gas supply process.

[0049] Figure 6 is a drawing showing the flow of washing solvent in the storage tank vacuuming process.

[0050] Figure 7 is a drawing showing the flow of washing solvent in the first liquid supply process.

[0051] Figure 8 is a drawing showing the flow of washing solvent in the first drain operation.

[0052] Figure 9 is a drawing showing the flow of the washing solvent in the first gas recovery process during the gas recovery process.

[0053] Figure 10 is a drawing showing the flow of washing solvent in a natural recovery process during a secondary gas recovery process.

[0054] Figure 11 is a flowchart illustrating a natural recovery process according to an embodiment of the present invention.

[0055] Figure 12 is a drawing showing the flow of washing solvent in a forced recovery process during a secondary gas recovery process.

[0056] Figure 13 is a flowchart illustrating a secondary gas recovery process according to another embodiment of the present invention.

[0057] Figure 14 is a configuration diagram of a washing machine according to another embodiment of the present invention.

[0058] Hereinafter, a washing device according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0059] Figure 1 is a configuration diagram of a washing device according to an embodiment of the present invention.

[0060] Referring to FIG. 1, a washing machine (10) according to an embodiment of the present invention includes a washing tank (110) in which laundry is put and the entire washing process is performed, a distillation tank (120) in which liquid carbon dioxide discharged from the washing tank (110) is stored, a compressor (130) which operates to supply gaseous carbon dioxide to the washing tank (110) or to recover gaseous carbon dioxide inside the washing tank (110), a gas storage tank (150) in which recovered carbon dioxide is stored, a vacuum pump (160) which lowers the internal pressure of the washing tank (110) or the gas storage tank (150) to a vacuum state, and a cooler (140) which absorbs heat from gaseous carbon dioxide and condenses it into liquid carbon dioxide.

[0061] In detail, the washing machine (10) may further include a contaminant storage tank (180) for storing contaminants generated during the washing process and collected inside the distillation tank (120).

[0062] In addition, a ventilation hole (111) may be provided on one side of the washing tub (110). In detail, when the pressure inside the washing tub (110) is lower than the external pressure, i.e., the atmospheric pressure, after the washing is completed, a situation occurs where the door of the washing tub (110) cannot be opened. In this case, the ventilation hole (111) is opened so that the pressure inside the washing tub (110) rises to the atmospheric pressure, thereby allowing the user to easily open the door. The ventilation hole (111) may be automatically opened and closed by a solenoid valve, or may be opened and closed manually by the user.

[0063] In addition, the components constituting the washing device (10) are connected to each other by a washing path (or washing pipe), so that gaseous carbon dioxide or liquid carbon dioxide circulates through the components along the washing path during the washing process.

[0064] In addition, a switching valve (190) and a plurality of opening / closing valves are installed on the washing path to control the flow and flow direction of the washing solvent flowing along the washing path.

[0065] The above washing machine includes a suction passage (205) connected to the suction port of the compressor (130) and a discharge passage (206) connected to the discharge port of the compressor (130). The switching valve (190) may be installed at an end of the discharge passage (206). The switching valve (190) may be a four-way valve having one inlet and three outlets.

[0066] The above laundry path may further include a gas sub-path (201) extending from an outlet of the switching valve (190). In detail, the gas sub-path (201) includes a storage tank-side gas sub-path (2011) extending from one of the outlets of the switching valve (190) and connected to the gas storage tank (150), and a washing tank-side gas sub-path (2012) extending from another of the outlets of the switching valve (190) and connected to the washing tank (110).

[0067] The above laundry path may include a gaseous main path (204) connecting the distillation tank (120) and the washing tank (110), and a liquid main path (203) extending from the remaining one of the outlets of the switching valve (190) and connected to the distillation tank (120).

[0068] A condensation path may be coupled to the above liquid main path (203). In detail, the condensation path may include a heat dissipation path (207) that branches from a certain point of the liquid main path (203), extends into the washing tank (110), and then merges with the liquid main path (203), and a condensation path (208) that branches from another point of the liquid main path (203), passes through the inside of the distillation tank (120), and then merges with the liquid main path (203).

[0069] In addition, the washing path may further include a liquid supply path (210) branched from a point of the main liquid path (203) and connected to the washing tub (110), and a liquid discharge path (209) extended from the washing tub (110) and connected to the liquid main path (203).

[0070] The above laundry path may further include a vacuum path (202) branched from a point of the storage tank-side gas sub-path (2011) and connected to the inlet of the vacuum pump (160), and a contaminant movement path (211) connecting the distillation tank (120) and the contaminant storage tank (180).

[0071] Meanwhile, the plurality of opening / closing valves installed in the washing passage may include opening / closing valves (V1, V14) installed in the gaseous main passage (204). The opening / closing valves (V1, V14) installed in the gaseous main passage (204) include an opening / closing valve (V14) installed between the distillation tank (120) and the point where the suction passage (205) branches, and an opening / closing valve (V1) installed between the point where the suction passage (205) branches and the washing tank (110).

[0072] The above plurality of on-off valves may further include an on-off valve (V2) installed at the inlet side of the heat dissipation passage (207), and an on-off valve (V3) installed at a point of the liquid main passage (203) corresponding to between the inlet and the outlet of the heat dissipation passage (207). When the on-off valve (V2) is opened and the on-off valve (V3) is closed, the gaseous carbon dioxide flowing along the liquid main passage (203) through the compressor (130) and the switching valve (190) is guided to the condensation passage (207) to supply heat to the inside of the washing tub (110) and then merge into the liquid main passage (203). On the other hand, when the on-off valve (V2) is closed and the on-off valve (V3) is opened, the gaseous carbon dioxide passing through the switching valve (190) flows along the liquid main passage (203).

[0073] The above-described plurality of opening / closing valves may further include an opening / closing valve (V4) installed in the washing tank-side gas sub-channel (2012), and opening / closing valves (V11, V8) installed on the liquid main channel (203). The opening / closing valve (V11) may be installed at any point of the liquid main channel (203) between the inlet and outlet of the condensation channel (208), so that the refrigerant flowing along the liquid main channel (203) may selectively flow into the condensation channel (208).

[0074] In addition, the above-mentioned opening / closing valve (V8) can be installed at any point of the above-mentioned liquid main flow path (203) between the point where the above-mentioned liquid supply flow path (210) branches and the point where the outlet of the above-mentioned liquid discharge flow path (209) merges.

[0075] The above plurality of opening / closing valves may further include an opening / closing valve (V15) installed in the liquid supply path (210), an opening / closing valve (V9) installed in the liquid discharge path (209), an opening / closing valve (V13) installed in the contaminant movement path (211), and an opening / closing valve (V6) installed on the vacuum path (202).

[0076] The above-described plurality of opening / closing valves may further include opening / closing valves (V5, V7) installed on the storage tank-side gas sub-channel (2011). The opening / closing valve (V5) is installed at a point between the switching valve (190) and the inlet of the vacuum channel (202). The opening / closing valve (V7) is installed at a point between the inlet of the vacuum channel (202) and the gas storage tank (150).

[0077] The above-described plurality of opening / closing valves may further include opening / closing valves (V10, V12) installed in the condensation path (208). The opening / closing valve (V10) is installed at a point where the condensation path (208) branches, and the opening / closing valve (V12) is installed at a point where the condensation path (208) merges with the liquid main path (203).

[0078] Below, with reference to the drawings, a detailed description is given of the phase and washing path along which the washing solvent flows for each course of the washing process.

[0079] Figure 2 is a flowchart showing the entire washing process performed in a washing device according to an embodiment of the present invention.

[0080] Referring to Fig. 2, a user opens the door of the washing tub (110), puts laundry in, closes the door, and presses the washing start button. Then, the compressor (130) operates to discharge air inside the washing tub (110) to the outside, thereby performing a washing tub vacuuming process to create a vacuum inside the washing tub (110) (S11).

[0081] When the above washing tank vacuuming process is completed, a gas supply process is performed in which gaseous carbon dioxide is supplied to the washing tank (110). In detail, the gas supply process includes a first gas supply process (S12) in which gaseous carbon dioxide recovered in the gas storage tank (150) is supplied to the washing tank (110), and a second gas supply process (S13) in which gaseous carbon dioxide within the distillation tank (120) is supplied to the washing tank (110).

[0082] The first gas supply process (S12) is performed until all of the carbon dioxide gas stored in the gas storage tank (150) is supplied to the washing tank (110). Then, after the first gas supply is completed, the second gas supply process (S13) is performed until the pressure inside the washing tank (110) reaches a set pressure. Here, the set pressure may be, for example, about 5.1 bar, but is not limited thereto. If the pressure inside the washing tank (110) reaches the set pressure only with the first gas supply, the second gas supply process (S13) may be omitted.

[0083] When the supply of carbon dioxide in a gaseous state is completed, a storage tank vacuuming process (S14) is performed to make the gas storage tank (150) into a vacuum state. By making the gas storage tank (150) into a vacuum state through the storage tank vacuuming process (S14), the carbon dioxide gas remaining in the washing tank (110) after the washing is completed can be recovered back into the gas storage tank (150).

[0084] When the storage tank vacuuming process (S14) is completed, the first liquid supply process is performed to supply liquid carbon dioxide to the washing tank (110) (S15). When the first liquid supply process is completed, the washing tank (110) repeats forward and reverse rotation, and the washing process is performed for a set time (S16).

[0085] When the set time has elapsed and the washing process is completed, the first drain process is performed (S17). Specifically, in the first drain process, the liquid carbon dioxide in the washing tank (110) is discharged into the distillation tank (120).

[0086] In order to prevent the pressure inside the washing tank (110) 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 (110) along with the discharge of the liquid carbon dioxide. The ventilation process may also be defined as a gas supply process.

[0087] In detail, when the above-described ventilation process begins, the compressor (130) operates to supply gaseous carbon dioxide in the distillation tank (120) to the washing tank (110). Then, since the pressure inside the washing tank (110) is maintained at a certain level during the process of discharging the liquid carbon dioxide, the liquid carbon dioxide is smoothly discharged.

[0088] In addition, during the liquid carbon dioxide discharge process, the washing tub (110) can be rotated in reverse order to allow the liquid carbon dioxide permeating the laundry to be discharged outside the washing tub (110). In addition, when the discharge of the liquid carbon dioxide is completed, the ventilation process is also terminated.

[0089] Meanwhile, when the first drain process is completed, a second liquid supply process is performed to supply liquid carbon dioxide into the washing tank (110) (S18). The second liquid supply process is performed in the same manner as the first liquid supply process described above.

[0090] When the secondary liquid supply is completed, the washing tub (110) repeats forward and reverse rotation for a set time to perform a laundry rinsing process (S19).

[0091] When the set time has elapsed and the rinsing cycle is completed, a second drain cycle is performed (S20), and the second drain cycle is performed in the same manner as the first drain cycle.

[0092] When the secondary drain process is completed, the primary gas recovery process is performed (S21) to recover the carbon dioxide gas present inside the washing tank to the distillation tank (120). The primary gas recovery process is completed when the pressure inside the washing tank (110) is lowered to a set pressure. Here, the set pressure may be approximately 2.5 bar, but is not limited thereto.

[0093] The above set pressure is determined by the allowable compression ratio of the compressor (130). The compression ratio can be defined as discharge pressure / suction pressure, and if the compressor (130) is operated under conditions exceeding the allowable compression ratio, the reliability of the compressor (130) may be exceeded, which may result in damage to the compressor or deterioration of its performance. Therefore, the above set pressure can be understood as a pressure corresponding to the allowable compression ratio of the compressor (130).

[0094] Here, the suction pressure corresponds to the pressure inside the washing tank (110), and the discharge pressure corresponds to the pressure inside the distillation tank (120). 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. Therefore, when the pressure inside the washing tank (110) reaches 2.5 bar during the recovery process, the gas recovery process can no longer be performed. In this state, the primary gas recovery process is terminated.

[0095] Even if the above first gas recovery process (S21) is completed, the pressure inside the washing tub (110) is higher than the pressure outside the washing tub (110), i.e., the atmospheric pressure, so the washing tub (110) cannot be opened. In this state, a second gas recovery process can be further performed to recover the gaseous carbon dioxide remaining inside the washing tub (110) into the gas storage tank (150) (S22).

[0096] Since the above gas storage tank (150) is in a vacuum state lower than atmospheric pressure, all or part of the carbon dioxide gas remaining inside the washing tank (110) can be recovered into the gas storage tank (150) through the secondary gas recovery process. Accordingly, the phenomenon of the washing solvent being discharged to the outside can be minimized.

[0097] In the above secondary gas recovery process, so-called "natural recovery" in which carbon dioxide gas is recovered naturally by the pressure difference between the washing tank (110) and the gas storage tank (150), and so-called "forced recovery" in which carbon dioxide gas is forcibly recovered by the compressor (130) may be selectively or sequentially performed. The above secondary gas recovery process will be described in more detail with reference to the flowchart below.

[0098] Meanwhile, when the process of recovering residual gas is completed and the pressure inside the washing tub (110) drops to atmospheric pressure or a pressure close to atmospheric pressure, the door of the washing tub (110) can be opened to take out the laundry. Alternatively, when the pressure inside the washing tub (110) is lower than atmospheric pressure, the ventilation hole (111) of the washing tub (110) can be opened automatically or manually to increase the pressure inside the washing tub (110) to atmospheric pressure, and then the door of the washing tub (110) can be opened to take out the laundry.

[0099] Below, the flow of the washing solvent for each step of the above-described washing process will be described in detail with reference to the drawings.

[0100] Figure 3 is a drawing showing the flow of air in the washing machine vacuum process.

[0101] Referring to Fig. 3, when laundry is placed inside the washing tub (110) and the door is closed, a washing tub vacuuming process is performed to create a vacuum inside the washing tub (110).

[0102] To this end, the opening / closing valves (V4, V5, V6) are opened, and the opening degree of the switching valve (190) is adjusted so that air existing inside the washing tub (110) is sucked into the vacuum pump (160) along the washing tub-side gas sub-channel (2012), the storage tank-side gas sub-channel (2011), and the vacuum channel (202). At this time, the opening / closing valve (V7) is kept closed to prevent air inside the washing tub (110) from flowing into the gas storage tank (150).

[0103] Here, the washing path connecting the washing tub (110) and the vacuum pump (160) can be defined as a “washing tub vacuum path.”

[0104] Figure 4 is a diagram showing the flow of washing solvent in the first gas supply process.

[0105] Referring to Fig. 4, when the first gas supply process starts while the inside of the washing tank (110) is in a vacuum state, the opening / closing valves (V7, V5, V4) are opened so that the gaseous carbon dioxide stored inside the gas storage tank (150) is supplied to the washing tank (110).

[0106] In detail, the gaseous carbon dioxide stored in the gas storage tank (150) is a laundry solvent recovered and stored during a previous washing process, and the carbon dioxide recovered in the gas storage tank (150) is first supplied to the washing tank (110), thereby emptying the gas storage tank (150). In addition, since the inside of the washing tank (110) is in a vacuum state and the gas storage tank (150) is maintained at a higher pressure than the washing tank (110), when the opening / closing valves (V7, V5, V4) are opened, so-called natural supply occurs in which carbon dioxide moves due to a pressure difference.

[0107] Here, the washing path connecting the gas storage tank (150) and the washing tank (110) can be defined as a “primary gas supply path.”

[0108] Figure 5 is a diagram showing the flow of washing solvent in the secondary gas supply process.

[0109] Referring to FIG. 5, when all of the gaseous carbon dioxide stored in the gas storage tank (150) in the first gas supply process is supplied to the washing tank (110), a second gas supply process is performed to supply the gaseous carbon dioxide stored in the distillation tank (120) to the washing tank (110) so that the washing tank (110) rises to a set pressure.

[0110] In detail, when the secondary gas supply process starts, the opening / closing valve (V14, V1) is opened, and the gaseous carbon dioxide inside the distillation tank (120) is naturally supplied to the washing tank (110) by the pressure difference. Then, when the internal pressure of the washing tank (110) reaches the set pressure, the opening / closing valve (V14, V1) is closed.

[0111] Here, the washing path connecting the distillation tank (120) and the washing tank (110) may be defined as a "secondary gas supply path." In addition, the primary and secondary gas supply paths may be defined collectively as a "gaseous washing solvent supply path."

[0112] Figure 6 is a drawing showing the flow of washing solvent in the storage tank vacuuming process.

[0113] Referring to FIG. 6, when the supply of gaseous carbon dioxide from the gas storage tank (150) and the distillation tank (120) to the washing tank (110) is completed, a storage tank vacuuming process is performed to make the storage tank (150) into a vacuum state.

[0114] As another example, the storage tank vacuuming process may be performed before the start of the secondary gas supply process.

[0115] When the vacuumization process of the storage tank starts, the on-off valves (V6, V7) are opened and the on-off valve (V5) is closed. Although the on-off valve (V5) is shown in the drawing as being installed at a point closer to the switching valve (190) than the inlet of the vacuum passage (202), it is to be noted that it is not limited thereto and may be installed adjacent to a point where the vacuum passage (202) branches. Then, the phenomenon of gaseous carbon dioxide remaining inside the storage tank-side gas sub-passage (2011) connecting the vacuum passage (202) and the on-off valve (V5) being discharged to the outside can be minimized.

[0116] If, in the first gas supply process, the gaseous carbon dioxide required for the washing tank (110) is sufficiently supplied and the gaseous carbon dioxide remains in the gas storage tank (150), the gas storage tank (150) may be separated after the first gas supply is completed, and the storage tank vacuuming process may be omitted.

[0117] Figure 7 is a drawing showing the flow of washing solvent in the first liquid supply process.

[0118] Referring to Fig. 7, when the pressure of the washing tank (110) reaches the set pressure by supplying gaseous carbon dioxide, a first liquid supply process is performed to condense the gaseous carbon dioxide stored in the distillation tank (120) and supply it into the washing tank (110).

[0119] In detail, when the first liquid supply process starts, the compressor (130) operates and the opening / closing valves (V14, V3, V11, V15) open. Then, the gaseous carbon dioxide stored in the distillation tank (110) flows along the gaseous main passage (204), the suction passage (205), the discharge passage (206), the liquid main passage (203), and the liquid supply passage (210) and is supplied into the washing tank (110).

[0120] At this time, the cooler (140) operates, and the gaseous carbon dioxide flowing along the liquid main path (203) after passing through the switching valve (190) is condensed and liquefied while passing through the cooler (140) and then supplied to the washing tank (110).

[0121] As another example, the above-mentioned opening / closing valve (V11) may be kept closed, and the opening / closing valves (V10, V12) may be opened so that the gaseous carbon dioxide passing through the switching valve (190) is first condensed while passing through the condensation path (208), and then secondarily condensed while passing through the cooler (140).

[0122] Here, the washing path connecting the distillation tank (120) and the washing tank (110) to supply liquefied carbon dioxide can be defined as a “liquid washing solvent supply path.”

[0123] Meanwhile, when the first liquid carbon dioxide supply is completed, all opening / closing valves are closed, and the washing cycle is performed while the washing tub (110) repeats forward and reverse rotation.

[0124] Figure 8 is a drawing showing the flow of washing solvent in the first drain operation.

[0125] Referring to Fig. 8, after the washing process is performed for a set time, a first drain process is performed to discharge the contaminated washing solvent, i.e., the contaminated liquid carbon dioxide, during the washing process.

[0126] In detail, when the rotation of the washing tub (11) stops, the opening / closing valve (V9) opens. Then, the liquid carbon dioxide inside the washing tub (110) is discharged to the distillation tank (120) along the liquid discharge path (209) and the liquid main path (203). At this time, the washing tub (110) can be rotated in reverse so that the liquid carbon dioxide absorbed in the laundry is also discharged.

[0127] In addition, in order to prevent the liquid carbon dioxide from being discharged smoothly as the pressure inside the washing tank (110) drops during the first drain operation, ventilation work (ventilation or gas supply) may be performed to supply gaseous carbon dioxide into the washing tank (110).

[0128] When the ventilation operation starts, the opening / closing valve (V14, V4) is opened and the compressor (130) is operated. Then, the gaseous carbon dioxide inside the distillation tank (120) flows along the gaseous main passage (204), the suction passage (205), the discharge passage (206), and the gaseous sub passage (2012) on the washing tank side and is supplied into the washing tank (110). Here, the washing passage connecting the distillation tank (120) and the washing tank (110) for the ventilation operation may be defined as a “ventilation passage.” And, the washing passage connecting the washing tank (110) and the distillation tank (120) for the discharge of the liquid carbon dioxide may be defined as a “liquid washing solvent discharge passage.”

[0129] In addition, when all of the liquid carbon dioxide inside the washing tank (11) is discharged to the distillation tank (14), the compressor (130) stops, and all of the opening / closing valves on the ventilation path and the liquid washing solvent discharge path are closed.

[0130] And, a secondary liquid supply process for rinsing is performed, and since the secondary liquid supply process is the same as the primary liquid supply process, a duplicate explanation is omitted.

[0131] Also, since the rinsing process is the same as the washing process described above, duplicate explanation is omitted.

[0132] And, when the rinsing process is completed, a second drain process is performed, and since the second drain process is also the same as the first drain process, a duplicate explanation is omitted.

[0133] Figure 9 is a drawing showing the flow of the washing solvent in the first gas recovery process during the gas recovery process.

[0134] In detail, when washing is completed, a gas recovery process is performed to recover the gaseous carbon dioxide remaining inside the washing tub (110) to the outside. The gas recovery process includes a first gas recovery process to recover the gaseous carbon dioxide remaining in the washing tub (110) to the distillation tank (120), and a second gas recovery process to recover it to the gas storage tank (150).

[0135] Among them, the first gas recovery process is performed first, and when the first gas recovery process starts, the compressor (130) and the cooler (140) are operated. Then, the opening / closing valves (V1, V2, V10, V12, V8) are opened, so that the gaseous carbon dioxide inside the washing tank (110) sequentially passes through the gaseous main passage (204), the suction passage (205), the discharge passage (206), the heat dissipation passage (207), the liquid main passage (203), the condensation passage (208), and the liquid main passage (203) and is recovered to the distillation tank (120).

[0136] The gaseous carbon dioxide that has passed through the compressor (130) and the switching valve (190) sequentially passes through the heat dissipation path (207), the condensation path (208), and the cooler (140) and is then phase-changed into liquid carbon dioxide and then recovered to the distillation tank (120).

[0137] The washing path connecting the washing tank (110) and the distillation tank (120) for gaseous carbon dioxide recovery can be defined as a “primary gas recovery path.”

[0138] Meanwhile, as carbon dioxide gas is discharged from the washing tub (11) during the gas recovery process, the pressure and temperature inside the washing tub (11) drop. As a result, the laundry may be damaged or moisture may condense on the surface of the laundry during the process of removing the laundry after the washing process is completed.

[0139] However, by allowing the high-temperature gaseous carbon dioxide passing through the compressor (130) and the switching valve (190) to release heat into the washing tub (110) while passing through the condensation path (207), the temperature inside the washing tub (110) can be prevented from becoming excessively low.

[0140] Figure 10 is a drawing showing the flow of washing solvent in a natural recovery process during a secondary gas recovery process.

[0141] Referring to Fig. 10, the secondary gas recovery process refers to a process in which the gaseous carbon dioxide remaining in the washing tank (110) is recovered to the gas storage tank (150).

[0142] In detail, the washing path through which gaseous carbon dioxide flows in the above secondary gas recovery process can be defined as a “secondary gas recovery path.”

[0143] The above secondary gas recovery process includes a natural recovery process in which gaseous carbon dioxide is recovered by pressure difference, as described above.

[0144] When the above natural recovery process starts, the opening / closing valves (V4, V5, V7) are opened, and the gaseous carbon dioxide inside the washing tank (110) flows along the washing tank-side gaseous sub-channel (2012) and the storage tank-side gaseous sub-channel (2011) and is recovered to the gas storage tank (150). The washing channel through which the gaseous carbon dioxide flows in the above natural recovery process can be defined as a "natural recovery channel."

[0145] Figure 11 is a flowchart illustrating a natural recovery process according to an embodiment of the present invention.

[0146] Referring to FIGS. 10 and 11, while the first gas recovery process is being performed, when the internal pressure of the washing tank (110) reaches a set pressure, i.e., a pressure corresponding to the compression ratio of the compressor (130), the first gas recovery process is terminated and a natural recovery process corresponding to the second gas recovery process is started.

[0147] When the above natural recovery process starts, the natural recovery path is opened and the gaseous carbon dioxide inside the washing tank (110) is recovered to the gas storage tank (150) (S221).

[0148] And, while the above natural recovery process is performed, the internal pressure of the washing tub (110) is detected at regular time intervals (S222). And, it is determined whether the current detected pressure is the same as the previous detected pressure (S223). If it is determined that the current detected pressure is lower than the previous detected pressure, it means that the gaseous carbon dioxide is moving from the washing tub (110) to the gas storage tank (150). On the other hand, if it is determined that the current detected pressure is the same as the previous detected pressure, it means that pressure equilibrium is achieved and the gaseous carbon dioxide no longer moves from the washing tub (110) to the gas storage tank (150).

[0149] Meanwhile, during the natural recovery process, the amount of gaseous carbon dioxide recovered into the gas storage tank (150) in a vacuum state may vary depending on the amount of gaseous carbon dioxide remaining inside the washing tub (110). As a result, the pressure inside the washing tub (110) in a pressure-balanced state may differ from the atmospheric pressure. Therefore, in order to allow the user to safely open the door of the washing tub (110), a process of adjusting the pressure inside the washing tub (110) in a pressure-balanced state to the atmospheric pressure is necessary.

[0150] In detail, if the previous detection pressure and the current detection pressure are determined to be equal, the natural recovery path is closed (S224). In this state, it is determined whether the current detection pressure is higher than atmospheric pressure (S225).

[0151] And, if the current detection pressure is determined to be higher than the atmospheric pressure, the gaseous carbon dioxide remaining inside the washing tub (110) is exhausted (S226). The exhaust of the gaseous carbon dioxide can be achieved by the operation of the vacuum pump (160). And, the exhaust of the gaseous carbon dioxide is performed until the pressure inside the washing tub (110) reaches the atmospheric pressure.

[0152] On the other hand, if the current detection pressure is determined to be lower than the atmospheric pressure, the ventilation hole is opened (S228) so that the internal pressure of the washing tank (110) rises to the atmospheric pressure.

[0153] And, if the current detected pressure is determined to be equal to the atmospheric pressure (S227), the natural recovery process is terminated. In this state, the user can easily open the door of the washing tub (110) and take out the laundry.

[0154] Figure 12 is a drawing showing the flow of washing solvent in a forced recovery process during a secondary gas recovery process.

[0155] Referring to FIG. 12, the secondary gas recovery process includes a forced recovery process by the compressor (130).

[0156] In detail, when the above-described forced recovery process starts, the compressor (130) operates, and at the same time, the opening / closing valves (V1, V5, V7) are opened, so that the gaseous carbon dioxide remaining inside the washing tank (110) flows along the gaseous main passage (204), the suction passage (205), the discharge passage (206), and the storage tank-side gaseous sub passage (2011) and is recovered to the gas storage tank (150).

[0157] In addition, the above-mentioned forced recovery process can be performed until the internal pressure of the washing tub (110) is lowered to atmospheric pressure. Therefore, at the point when the above-mentioned forced recovery process is completed, the internal pressure of the washing tub (110) is lowered to atmospheric pressure, so that the user can easily open the door of the washing tub (110) and take out the laundry.

[0158] Here, the washing path through which gaseous carbon dioxide flows in the above-mentioned forced recovery process can be defined as a “forced recovery path.”

[0159] At the end of the forced recovery process, gaseous carbon dioxide may still remain inside the washing tub (110). In this case, the gaseous carbon dioxide will be exhausted into the atmosphere when the user opens the door of the washing tub (110) to take out the laundry.

[0160] Figure 13 is a flowchart illustrating a secondary gas recovery process according to another embodiment of the present invention.

[0161] The secondary gas recovery process according to the present embodiment is characterized in that the natural recovery process is performed first, and then the forced recovery process is performed.

[0162] In detail, when the internal pressure of the washing tank (110) reaches a set pressure corresponding to the compression ratio, the first gas recovery process ends and the second gas recovery process starts.

[0163] When the secondary gas recovery process begins, as described in Fig. 11, the natural recovery path is opened (S31), and the gaseous carbon dioxide inside the washing tank (110) is recovered to the gas storage tank (150) by the pressure difference.

[0164] Then, the pressure inside the washing tank is periodically detected (S32), and it is determined whether the current detected pressure has reached a level pressure state where it is the same as the previous detected pressure (S33).

[0165] In detail, if it is determined that the inside of the washing tub (110) has reached an equilibrium pressure, the natural recovery path is closed and the natural recovery process is terminated (S34). Then, it is determined whether the current sensed pressure, i.e., the pressure in the equilibrium state, is higher than the atmospheric pressure (S35). If it is determined that the current sensed pressure is higher than the atmospheric pressure, the forced recovery path is opened and the compressor is operated (S36), so that the gaseous carbon dioxide inside the washing tub (110) is forcibly recovered to the gas storage tank (150). Then, the forced recovery process is performed until the pressure of the washing tub (110) reaches the atmospheric pressure.

[0166] On the other hand, if the current detection pressure is determined to be lower than the atmospheric pressure, the ventilation hole is opened so that the internal pressure of the washing tank (110) rises to the atmospheric pressure.

[0167] And, if the current detected pressure is determined to be equal to the atmospheric pressure (S37), the natural recovery process is terminated. In this state, the user can easily open the door of the washing tub (110) and take out the laundry.

[0168] Figure 14 is a configuration diagram of a washing machine according to another embodiment of the present invention.

[0169] Referring to FIG. 14, a washing machine (10a) according to another embodiment of the present invention may further include a mixer (170), a detergent container (171), and an additive container (172) in addition to the configuration of the washing machine (10) according to the previous embodiment.

[0170] In detail, the mixer (170) can be defined as a space where the detergent stored in the detergent container (171), the additive stored in the additive container (172), and the gaseous carbon dioxide stored in the gas storage tank (150) are mixed.

[0171] The above mixer (170) can be connected to any point on the storage tank-side gas phase sub-channel (2011) between the point where the vacuum channel (202) branches and the switching valve (190) or the opening / closing valve (V5). Each of the detergent container (171) and the additive container (172) can be connected to the mixer (170).

[0172] And, when the first gas supply process begins, the gaseous carbon dioxide stored in the gas storage tank (150), detergent, and additives can be mixed in the mixer (170) and then supplied to the washing tank (110).

[0173] Since the other washing operations are the same as the washing operations performed in the washing device (10) according to the previous embodiment, duplicate descriptions are omitted.

Claims

1. Washing tub where laundry is put; A distillation tank connected to the washing tank, supplying carbon dioxide to the washing tank or storing carbon dioxide recovered from the washing tank; A compressor connected to the washing tank and the distillation tank, and compressing gaseous carbon dioxide stored in the washing tank or the distillation tank; A condensing cooler that liquefies the gaseous carbon dioxide that has passed through the compressor; A gas storage tank in which gaseous carbon dioxide recovered from the washing tank is stored after washing is completed; and A washing machine including a washing path connecting the washing tank, the distillation tank, the compressor, the cooler, and the gas storage tank.

2. In paragraph 1, A washing machine further comprising a vacuum pump for evacuating the washing tank or the gas storage tank.

3. In paragraph 2, The above gas storage tank, A washing machine characterized by a container in which the carbon dioxide remaining after being first recovered from the washing tank to the distillation tank is secondarily recovered and stored.

4. In paragraph 3, A washing machine characterized in that, after washing is completed, the carbon dioxide recovered and stored in the gas storage tank is resupplied into the washing tank, which is in a vacuum state, during the next washing process.

5. In paragraph 4, The above laundry euro is, A washing machine including a washing tank vacuum passage connecting the washing tank and the vacuum pump in a washing tank vacuuming process.

6. In paragraph 4, The above laundry euro is, In the above first gas supply process, a first gas supply path is included that connects the gas storage tank and the washing tank in a vacuum state, A washing machine characterized in that the carbon dioxide stored in the gas storage tank is naturally supplied by the pressure difference between the gas storage tank and the washing tank.

7. In paragraph 4, The above laundry euro is, In the secondary gas supply process, a secondary gas supply path is included that connects the distillation tank and the washing tank, A washing machine characterized in that the carbon dioxide stored in the distillation tank is naturally supplied by the pressure difference between the washing tank and the distillation tank until the pressure inside the washing tank increases to a set pressure.

8. In paragraph 4, The above laundry euro is, A washing machine comprising a storage tank vacuuming path connecting the storage tank and the vacuum pump in a storage tank vacuuming process.

9. In paragraph 4, The above laundry euro is, In the liquid supply process, a liquid supply path is included that connects the distillation tank, the compressor, the cooler, and the washing tank, A washing machine characterized in that the gaseous carbon dioxide stored in the distillation tank is liquefied while passing through the cooler and then supplied to the washing tank.

10. In paragraph 9, The above liquid supply flow rate is: Connecting the outlet of the compressor and the inlet of the cooler, and including a condensation path passing through the interior of the distillation tank, Carbon dioxide flowing along the above condensation path is first condensed while exchanging heat with liquid carbon dioxide stored in the distillation tank, A washing machine characterized in that carbon dioxide passing through the above condensation path is secondarily condensed while passing through the above cooler.

11. In paragraph 4, The above laundry euro is, In the drain operation, a drain path is included connecting the washing tank and the distillation tank, A washing machine characterized in that after the washing cycle or rinsing cycle is completed, the liquid carbon dioxide inside the washing tank is discharged to the distillation tank.

12. In paragraph 4, The above laundry euro is, In the first gas recovery process, a first gas recovery path is included that connects the washing tank, the compressor, the distillation tank, and the cooler, The carbon dioxide inside the washing tank is sucked into the compressor, Carbon dioxide discharged from the compressor is first condensed while passing through a heat dissipation passage penetrating the inside of the washing tank and exchanging heat with the carbon dioxide remaining inside the washing tank. Carbon dioxide passing through the above heat dissipation path is condensed for the second time while exchanging heat with the liquid carbon dioxide inside the distillation tank while passing through the condensation path penetrating the inside of the distillation tank. A washing machine characterized in that carbon dioxide passing through the condensation path is liquefied while passing through the cooler and then recovered to the distillation tank.

13. In paragraph 4, The above laundry euro is, A washing machine including a secondary gas recovery path connecting the washing tank and the storage tank in a secondary gas recovery process.

14. In paragraph 13, The above secondary gas recovery path is, Including a natural recovery path directly connecting the washing tank and the gas storage tank in a vacuum state, A washing machine characterized in that the carbon dioxide gas remaining in the washing tank is naturally recovered by the pressure difference between the washing tank and the gas storage tank.

15. In paragraph 14, The above secondary gas recovery path is, Including a forced recovery path connecting the washing tank, the compressor, and the gas storage tank, A washing machine characterized in that the gaseous carbon dioxide remaining in the washing tub after the natural recovery is forcibly recovered from the washing tub to the gas storage tank by the compressor.

16. In paragraph 6, A mixer placed on the primary gas supply path; a detergent container connected to the above mixer; and Further comprising an additive container connected to the above mixer, A washing machine characterized in that carbon dioxide supplied from the gas storage tank, detergent supplied from the detergent container, and additive supplied from the additive container are mixed in the mixer and then supplied to the washing tub.

17. When laundry is placed inside the washing machine and the washing machine door is closed, the washing process is performed. The above washing process is, Washing machine vacuuming process in which the inside of the washing machine is lowered into a vacuum state; A gas supply process in which gaseous carbon dioxide is supplied into the washing tank; A liquid supply process in which liquid carbon dioxide is supplied into the washing tank; Laundry administration; Rinsing cycle; Drainage process to drain contaminated liquid carbon dioxide; A primary gas recovery process for recovering carbon dioxide gas inside the washing tank to a distillation tank; and A control method for a washing machine including a secondary gas recovery process for recovering gaseous carbon dioxide inside a washing tank to a gas storage tank.

18. In paragraph 17, The above gas supply administration is, A primary gas supply process in which the carbon dioxide gas recovered in the above gas storage tank is naturally supplied to the washing tank by a pressure difference; and A control method for a washing machine including at least one of a secondary gas supply process in which gaseous carbon dioxide stored in the distillation tank is naturally supplied to the washing tank by a pressure difference.

19. In paragraph 18, When the above first gas supply process is completed, a storage tank vacuuming process is performed to make the gas storage tank into a vacuum state, A control method for a washing machine, characterized in that one of the storage tank vacuuming process and the secondary gas supply process is performed before the other.

20. In paragraph 17, The above liquid supply administration is, The first liquid supply process performed before the above washing process; and A method for controlling a washing machine including a secondary liquid supply process performed before the above rinsing process.

21. In paragraph 17, The above drain process is, The first drain operation performed after the above washing operation; and A method for controlling a washing machine including a secondary drain operation performed after the above rinsing operation.

22. In paragraph 17, The above first gas recovery process is, When the internal pressure of the washing machine reaches the set pressure, it is terminated. A control method for a washing machine, characterized in that the above-mentioned set pressure is a pressure corresponding to the compression ratio of the compressor.

23. In paragraph 22, The above secondary gas recovery process is, A control method for a washing machine including a natural recovery process in which carbon dioxide remaining in the washing tank after the first gas recovery process is recovered to the gas storage tank by a pressure difference.

24. In paragraph 23, When the above natural recovery process begins, The natural recovery path connecting the above washing tank and the above gas storage tank is opened, A control method for a washing machine, characterized in that the natural recovery path is closed when the pressure inside the washing tank reaches a constant pressure state.

25. In paragraph 24, When the pressure inside the washing tank is higher than the atmospheric pressure in the above-mentioned equilibrium state, the gaseous carbon dioxide remaining inside the washing tank is exhausted into the atmosphere. When the pressure inside the washing tub is lower than atmospheric pressure, the ventilation hole of the washing tub is opened. A control method for a washing machine, characterized in that when the pressure inside the washing tank is equal to atmospheric pressure, the secondary gas recovery process is terminated.

26. In paragraph 22, The above secondary gas recovery process is, A control method for a washing machine including a forced recovery process in which carbon dioxide remaining in the washing tank after the first gas recovery process is forcibly recovered to the gas storage tank by a compressor.

27. In paragraph 26, When the above mandatory recovery process begins, The compressor operates with the forced recovery path connecting the washing tank, the compressor, and the gas storage tank open, A control method for a washing machine, characterized in that the above-mentioned forced recovery process is performed until the pressure inside the washing tub reaches atmospheric pressure.

28. In paragraph 22, The above secondary gas recovery process is, A natural recovery process in which the carbon dioxide remaining in the washing tank after the first gas recovery process is naturally recovered into the gas storage tank; A control method for a washing machine including a forced recovery process in which carbon dioxide remaining in the washing tank after the natural recovery process is forcibly recovered to the gas storage tank by a compressor.

29. In paragraph 28, When the above natural recovery process begins, The natural recovery path connecting the above washing tank and the above gas storage tank is opened, When the pressure inside the washing tank reaches a constant pressure state, the natural recovery path is closed. If the pressure inside the washing tank is higher than the atmospheric pressure in the above-mentioned equilibrium state, the forced recovery process is performed, When the pressure inside the washing tub is lower than atmospheric pressure, the ventilation hole of the washing tub is opened. A control method for a washing machine, characterized in that when the pressure inside the washing tank is equal to atmospheric pressure, the secondary gas recovery process is terminated.

30. In paragraph 29, When the above mandatory recovery process begins, The compressor operates with the forced recovery path connecting the washing tank, the compressor, and the gas storage tank open, A control method for a washing machine, characterized in that the above-mentioned forced recovery process is performed until the pressure inside the washing tub reaches atmospheric pressure.

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