Washing machine and control method thereof

Abstract

A washing machine according to an embodiment of the present invention comprises: a washing tub into which laundry is loaded; a storage tank that supplies carbon dioxide to the washing tub; a distillation tank in which liquid-phase carbon dioxide discharged from the washing tub collects; a compressor that compresses gas-phase carbon dioxide in the distillation tank and sends the compressed carbon dioxide to the washing tub or the storage tank; a cooler that condenses the gas-phase carbon dioxide, discharged from the compressor and supplied to the storage tank, into liquid-phase carbon dioxide; a differential pressure replenishment passage that connects the washing tub and a bomb provided to replenish carbon dioxide diminished through repeated washing processes; a compression replenishment passage that branches off at a point in the differential pressure replenishment passage to connect the compressor to the washing tub; and a switching valve provided at the branching point of the differential pressure replenishment passage.

Description

Washing machine and its control method

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

[0002] In a waterless washing machine using carbon dioxide, a certain amount of carbon dioxide remaining in the washing tub after a single wash cycle is vented rather than recovered. As this exhausted carbon dioxide accumulates, the carbon dioxide level in the storage tank drops below a set level. Then, a carbon dioxide tank is connected, allowing the carbon dioxide stored in the tank to be supplied directly to the washing tub, replenishing the lost carbon dioxide.

[0003] The carbon dioxide replenishment process is performed after the vacuum process, which reduces the internal pressure of the washing tub after the start of the washing process, is completed. Specifically, if the water level in the reservoir is determined to have fallen below a set level, a carbon dioxide-filled cylinder is connected to the supply line connecting the reservoir and the washing tub, allowing gaseous carbon dioxide to be supplied directly from the cylinder to the washing tub.

[0004] As carbon dioxide is supplied from the cylinder to the washing tub, the pressure inside the cylinder drops. When the pressure inside the cylinder equals the pressure in the washing tub, the cylinder ceases to supply carbon dioxide. The washing process then proceeds without the carbon dioxide being fully replenished, and the cylinder is disconnected from the supply line.

[0005] At the time of separation, the pressure inside the bomb is approximately 5 to 15 bar, and the amount of carbon dioxide remaining is approximately 2 to 5 kg per 20 kg container. There is a problem that carbon dioxide equivalent to 10 to 25% of the total amount is not used and is disposed of.

[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 washing machine according to an embodiment of the present invention comprises: a washing tub into which laundry is put; a storage tub for supplying carbon dioxide to the washing tub; a distillation tub for collecting liquid carbon dioxide discharged from the washing tub; a compressor for compressing gaseous carbon dioxide in the distillation tub and sending it to the washing tub or the storage tub; a cooler for condensing gaseous carbon dioxide discharged from the compressor and supplied to the storage tub into liquid carbon dioxide; a differential pressure replenishment channel connecting a bomb provided to replenish carbon dioxide reduced through repeated washing processes and the washing tub; a compression replenishment channel branched at a certain point of the differential pressure replenishment channel and connecting the compressor and the washing tub; and a switching valve provided at a point where the differential pressure replenishment channel branches.

[0009] The washing machine according to the present invention further includes a main valve provided at a point of the differential pressure supplementary flow path, and a sub valve provided at a point of the compression supplementary flow path.

[0010] The point at which the above-mentioned differential pressure supplementary flow path branches is characterized in that it is a point corresponding to the inlet side of the main valve based on the flow direction of carbon dioxide flowing along the above-mentioned differential pressure supplementary flow path.

[0011] The above compression supplementary flow path is a flow path connecting a point where the differential pressure supplementary flow path branches, the inlet of the compressor, the outlet of the compressor, and the washing tub, and the sub-valve is provided at any point on the flow path connecting the outlet of the compressor and the washing tub.

[0012] When the main valve is opened, carbon dioxide is supplied from the bomb to the washing tub due to the pressure difference between the bomb and the washing tub, and when the pressures of the bomb and the washing tub become equal, the main valve is closed, the switching valve is operated, and the flow direction is switched to the compression supplementary path.

[0013] When the flow direction of the carbon dioxide is switched to the compression replenishment path, the compressor operates and the sub-valve opens, so that carbon dioxide is forcibly replenished from the bomb to the washing tank.

[0014] The washing machine according to the present invention further includes a differential pressure supply path connecting the storage tank and the washing tank.

[0015] A part of the above differential pressure supplementary flow path shares the above differential pressure supply flow path, so that the outlet of the above differential pressure supplementary flow path is the same as the outlet of the above differential pressure supply flow path, and the above main valve is provided on the above differential pressure supply flow path.

[0016] The above differential pressure supplementary flow path and the above differential pressure supply flow path form independent flow paths, and the outlet of the differential pressure supplementary flow path and the outlet of the differential pressure supply flow path are respectively connected to different ports formed in the washing tank.

[0017] The outlet of the above compression supplementary flow path is characterized in that it is joined at some point of the above differential pressure supplementary flow path.

[0018] The outlet of the above pressure differential supplementary flow path is characterized in that it is joined at a point of the above pressure differential supplementary flow path corresponding to the outlet side of the main valve based on the flow direction of carbon dioxide flowing along the above pressure differential supplementary flow path.

[0019] The outlet of the above compression supplementary flow path and the outlet of the above differential pressure supplementary flow path are characterized in that they are respectively connected to different ports formed in the washing tank.

[0020] A control method for a washing machine according to an embodiment of the present invention comprises the steps of: placing laundry into a washing tub and closing a washing tub door; lowering the pressure inside the washing tub to a vacuum state; supplying carbon dioxide from a storage tank to the washing tub; and performing a washing cycle; wherein, when the inside of the washing tub becomes a vacuum state, a level of liquid carbon dioxide inside the storage tank is sensed; and, if the sensed level is lower than a set level, a carbon dioxide replenishment process is performed to replenish carbon dioxide from a separately connected bomb to the washing tub; wherein, when the carbon dioxide replenishment process is started, a main valve installed on a differential pressure replenishment passage connecting the bomb and the washing tub is opened, and a natural replenishment process is performed in which carbon dioxide naturally flows from the bomb to the washing tub due to a pressure difference between the bomb and the washing tub; wherein, if the pressure of the bomb and the pressure of the washing tub become equal before the pressure of the washing tub reaches a replenishment set pressure, the main valve is closed to stop the natural replenishment process; and wherein, if a forced replenishment process using the compressor is performed, the main valve is closed.

[0021] The above-mentioned supplementary set pressure is characterized by being a pressure inside the washing tank detected when an amount of carbon dioxide corresponding to the reduced water level is supplied to the washing tank.

[0022] The supply of carbon dioxide through the above-mentioned forced replenishment process is characterized in that it is carried out along a forced replenishment path connecting the bomb, the compressor, and the washing tub, and is selectively carried out by opening and closing a sub-valve provided on the forced replenishment path connecting the compressor and the washing tub.

[0023] When the above-mentioned forced replenishment process starts, the compressor operates with the opening of the sub-valve, so that the carbon dioxide inside the bomb is sucked into the compressor and then compressed and supplied to the washing tank.

[0024] When the pressure of the washing tank reaches the supplementary set pressure, the compressor is stopped, the sub-valve is closed, and the washing process is subsequently performed.

[0025] Before the pressure of the washing tank reaches the supplementary set pressure, if the suction pressure of the compressor decreases below the replacement pressure of the bomb, the compressor is stopped and the sub-valve is closed.

[0026] A control method of a washing machine according to an embodiment of the present invention is characterized in that a bomb replacement alarm is generated simultaneously or sequentially with the closing of the sub-valve.

[0027] A control method of a washing machine according to an embodiment of the present invention is characterized in that the washing process is continuously performed after the sub-valve is closed or the bomb replacement alarm is generated.

[0028] According to the washing machine and its control method according to the embodiment of the present invention having the above configuration, the following effects are obtained.

[0029] Specifically, during the carbon dioxide replenishment process, if the cylinder pressure falls below the replenishment completion pressure and the carbon dioxide replenishment is difficult solely through the differential pressure between the cylinder and the washing tub, the cylinder can be connected to a compressor, which supplies the carbon dioxide inside the cylinder to the washing tub. This effectively maximizes the utilization of the carbon dioxide remaining inside the cylinder. As a result, the amount of unused and discarded carbon dioxide can be minimized, resulting in cost savings.

[0030] Figure 1 is a drawing showing the configuration of a washing machine according to an embodiment of the present invention.

[0031] Figures 2 to 7 are diagrams showing the flow of carbon dioxide throughout the entire washing process.

[0032] Figure 8 is a drawing showing a process of naturally replenishing carbon dioxide from a bomb to a washing tub, and Figure 9 is a drawing showing a process of forcibly replenishing carbon dioxide from a bomb to a washing tub.

[0033] Figure 10 is a flowchart explaining the carbon dioxide replenishment process.

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

[0035] FIG. 1 is a drawing showing the configuration of a washing machine according to an embodiment of the present invention.

[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 tank (11) in which laundry is put and the entire washing process is performed, a storage tank (12) in which carbon dioxide supplied to the washing tank (11) is stored, a distillation tank (14) in which liquid carbon dioxide after the washing process is stored, a cooler (15) for changing the phase of gaseous carbon dioxide recovered to the storage tank (12) into liquid carbon dioxide during the recovery process, and a compressor (13) for compressing gaseous carbon dioxide stored in the distillation tank (14) and supplying it to the washing tank or compressing gaseous carbon dioxide in the washing tank and recovering it to the storage tank (12). In addition, a bomb (16) filled with carbon dioxide may be connected to a carbon dioxide supply line connecting the storage tank (12) and the washing tank (11).

[0038] An exhaust port (DP) is provided on one side of the above washing tank (11), and a vacuum pump (19) is installed at a certain point of the exhaust path connected to the exhaust port (DP).

[0039] The washing tank (11), storage tank (12), distillation tank (14), and compressor (13) are connected to each other by pipes to form a circulation path. In detail, the circulation path may include a differential pressure supply path (101), a compression supply path (102), a recovery path (103), a differential pressure supplement path (104), a compression supplement path (105), a discharge path (106), and a liquid supply path (107). These paths are described in detail below with reference to the drawings. In addition to these paths, it should be noted that the paths described below may be designed to overlap in some sections, or all paths may form independent paths.

[0040] And, the supply of carbon dioxide by differential pressure described below means that carbon dioxide is supplied by a phenomenon in which carbon dioxide naturally flows from a chamber with high pressure to a chamber with low pressure.

[0041] Inside the storage tank (12), carbon dioxide in a gaseous state and carbon dioxide in a liquid state are stored together, and as the washing and rinsing process is performed, carbon dioxide circulates between the storage tank (12) and the washing tank (11).

[0042] Below, the flow of carbon dioxide throughout the entire washing process is described in detail with reference to the drawings.

[0043] In addition, a main valve (17) is installed at a certain point in the pipe (channel) connecting the storage tank (12) and the washing tank (11), specifically, at a point adjacent to the washing tank (11). In addition, a sub-valve (18) is installed at a certain point in the pipe (channel) connecting the outlet of the compressor (13) and the washing tank (11), and the main valve (17) and the sub-valve (18) are opened or closed in the carbon dioxide replenishment process.

[0044] Figures 2 to 7 are diagrams showing the flow of carbon dioxide throughout the entire washing process.

[0045] Referring to Fig. 2, when a user opens the door of the washing tub (11), puts in laundry, closes the door, and presses the washing start button, the vacuum pump (19) connected to the exhaust port (DP) 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).

[0046] Referring to Fig. 3, when the inside of the washing tub (11) becomes a vacuum state, the differential pressure supply passage (101) connecting the storage tank (12) and the washing tub (11) is opened so that the carbon dioxide in a gaseous state stored in the storage tank (12) is supplied to the washing tub (11) by the pressure difference. At this time, the main valve (17) is opened to enable the flow of carbon dioxide. It should be noted that, in addition to the main valve (17), additional valves may be installed on the differential pressure supply passage (101).

[0047] The pressure inside the storage tank (12) is approximately 50 bar, and as carbon dioxide moves from the storage tank (12) to the washing tank (11) through the differential pressure supply path (101), the internal pressure of the storage tank (12) drops and the internal pressure of the washing tank (11) increases. Then, when the pressure of the storage tank (12) and the pressure of the washing tank (11) become equal to each other and reach a balanced pressure state, the on-off valves including the main valve (17) are closed, thereby closing the differential pressure supply path (101). When the flow of the gaseous carbon dioxide stops, it can be considered that the supply of the gaseous carbon dioxide is completed.

[0048] Referring to Fig. 4, when the supply of carbon dioxide in a gaseous state is completed, the liquid carbon dioxide stored in the storage tank (12) is supplied to the washing tank (11) through the liquid supply path (107) connecting the storage tank (12) and the washing tank (11). The liquid supply path (107) is a path indicated by a dotted arrow in the drawing. Here, the storage tank (12) is located at a higher point than the washing tank (11), so that the liquid carbon dioxide can be supplied to the washing tank (11) by gravity.

[0049] In detail, as liquid carbon dioxide is supplied to the washing tank (11) through the liquid supply path (107), the pressure inside the washing tank (11) may increase, thereby slowing down the supply speed of the liquid carbon dioxide. To prevent this phenomenon, a ventilation process is performed in parallel to suppress the increase in pressure inside the washing tank (11) by discharging the gaseous carbon dioxide supplied inside the washing tank (11) and returning it to the storage tank (12).

[0050] The path indicated by the solid arrow in the drawing is a path through which gaseous carbon dioxide is recovered from the washing tank (11) toward the storage tank (12), and can be defined as a so-called reverse ventilation path (108). The reverse ventilation path (108) passes through the washing tank (11), the compressor (13), and the cooler (15) and is connected to the storage tank (12).

[0051] The compressor (13) sucks in and compresses the gaseous carbon dioxide inside the washing tub (11) and returns it to the storage tank (12), and at this time, the cooler (15) is kept in a stopped state so that the carbon dioxide discharged from the washing tub (11) returns to the storage tank (12) in a gaseous state. Alternatively, it is not excluded that the cooler (15) operates so that the carbon dioxide returns to the storage tank (12) in a liquid state.

[0052] Meanwhile, the supply of the liquid carbon dioxide is carried out for a set period of time, and when the set period of time has elapsed, the valve (not shown) installed in the liquid supply path (107) is closed to stop the supply of carbon dioxide. At the same time, the reverse ventilation path (108) is also closed to stop the ventilation process.

[0053] Here, the reverse ventilation path (108) does not pass through the cooler (15), but does not exclude the possibility of forming a separate independent path (108a) indicated by a dashed line in the drawing.

[0054] In addition, although the reverse ventilation path (108) is illustrated as sharing a portion of the differential pressure supply path (101) and the main valve (17), it should be noted that this is not limited thereto. For example, it may be possible for a ventilation port to be installed on one side of the washing tub (11), and for the suction end of the reverse ventilation path (108) to be connected to the ventilation port.

[0055] Once the supply of carbon dioxide gas and liquid carbon dioxide is complete, washing takes place within the washing tub (11). Here, the term "washing tub (11)" can be understood as a term including a fixed tub and a drum rotating within the tub. Accordingly, during the washing process, the drum rotates, mixing the laundry placed within the drum with the liquid carbon dioxide, thereby completing the washing process.

[0056] Then, when the set time has elapsed and the washing process is completed, a process of discharging liquid carbon dioxide mixed with contaminants separated from the laundry is performed.

[0057] Referring to Fig. 5, as indicated by the dotted arrow, the discharge path (106) is opened to discharge liquid carbon dioxide, and the liquid carbon dioxide inside the washing tank (11) is discharged to the distillation tank (14).

[0058] At this time, as the liquid carbon dioxide exits the washing tub (11), the pressure inside the washing tub (11) decreases, which may slow down the discharge rate of the liquid carbon dioxide. To prevent this phenomenon, a ventilation process is also performed to maintain the pressure inside the washing tub (11) at the same level.

[0059] That is, the gaseous carbon dioxide stored in the distillation tank (14) is supplied to the washing tank (11) by the compressor (13) along the forward ventilation path (109) connecting the distillation tank (14), the compressor (13), and the washing tank (11). Here, since the gaseous carbon dioxide is supplied to the washing tank (11) for ventilation, the ventilation path (109) that is opened during the discharge process of the liquid carbon dioxide can be defined as a forward ventilation path.

[0060] As liquid carbon dioxide is supplied from the washing tank (11) to the distillation tank (14), the water level of the distillation tank (14) increases, but since gaseous carbon dioxide escapes into the washing tank (11) by the operation of the compressor (13), the pressure inside the distillation tank (14) does not change.

[0061] Meanwhile, when all of the contaminated liquid carbon dioxide remaining inside the washing tank (11) is discharged to the distillation tank (14), a liquid carbon dioxide supply process for rinsing is performed.

[0062] Referring to Fig. 6, liquid carbon dioxide inside the storage tank (12) is supplied to the washing tank (11) through the liquid supply path (107). Here, since the inside of the washing tank (11) is filled with gaseous carbon dioxide, only liquid carbon dioxide for rinsing is supplied to the washing tank (11).

[0063] And, as the liquid carbon dioxide inside the storage tank (12) is discharged, the water level decreases. To compensate for this, the compressor (13) operates so that the gaseous carbon dioxide stored inside the distillation tank (14) is changed into a liquid phase and then supplied to the storage tank (12).

[0064] In detail, the flow path connecting the distillation tank (14), the compressor (13), the cooler (15) and the storage tank (12) can be defined as a liquid supplement flow path (110), and is indicated by an arrow connecting a solid line and a dotted line in the drawing.

[0065] As the water level inside the storage tank (12) decreases, in order to compensate for this, the compressor (13) sucks and compresses the gaseous carbon dioxide from the distillation tank (14) and sends it to the refrigerator (15). Then, the gaseous carbon dioxide discharged from the compressor (13) is condensed while passing through the refrigerator (15), changes into liquid carbon dioxide, and then flows into the storage tank (12).

[0066] When the liquid carbon dioxide required for the rinsing process is supplied to the washing tank (11), the rinsing process is performed. Then, when the rinsing process is completed, a process of discharging both the gaseous carbon dioxide and the liquid carbon dioxide inside the washing tank (11) is performed.

[0067] Referring to Fig. 7, when washing and rinsing are completed, an ideal carbon dioxide recovery process for recovering gaseous carbon dioxide into a storage tank (12) and a liquid carbon dioxide discharge process for discharging liquid carbon dioxide into the distillation tank (14) are performed simultaneously.

[0068] The discharge path (106) and discharge process of the above liquid carbon dioxide have already been described in the description of the discharge process before rinsing, so a duplicate description will be omitted.

[0069] And, first, regarding the gaseous carbon dioxide recovery process performed together with the liquid carbon dioxide emission, the gaseous carbon dioxide recovery path (111) indicated by a solid line in the drawing can be defined as a path connecting the washing tank (11), the compressor (13), the distillation tank (14), the refrigerator (15), and the storage tank (12).

[0070] In detail, in order to recover the vaporous carbon dioxide, the valves installed on the vaporous carbon dioxide recovery path (111), including the main valve (11), are opened to allow the flow of carbon dioxide.

[0071] In the drawing, the suction end of the gaseous carbon dioxide recovery path (111) is shown to overlap with a portion of the differential pressure supply path (101), but this is not limited thereto. In other words, a port for recovery of gaseous carbon dioxide is provided on one side of the washing tank (11), and the suction end of the gaseous carbon dioxide recovery path (111) is connected to the port for recovery of gaseous carbon dioxide to form an independent path.

[0072] In addition, a portion of the gaseous carbon dioxide recovery path (111) extending from the outlet of the compressor (13) is designed to pass through the inside of the washing tub (11). The high-temperature gaseous carbon dioxide flowing along the path extending into the inside of the washing tub (11) does not mix with the gaseous carbon dioxide remaining inside the washing tub (11) and only releases heat.

[0073] Here, as the liquid carbon dioxide inside the washing tub (11) is discharged to the distillation tank (14), the temperature and pressure inside the washing tub (11) may decrease, which may delay the discharge of the liquid carbon dioxide. However, the decrease in the temperature inside the washing tub (11) can be minimized by heat exchange occurring in the passage portion extending inside the washing tub (11), thereby preventing the phenomenon of delayed discharge of the liquid carbon dioxide. In addition, when the laundry is taken out after washing is completed, the temperature inside the washing tub is significantly lower than the outside temperature, which can prevent the phenomenon of moisture condensing on the surface of the laundry when the laundry is taken out.

[0074] In addition, a portion of the path connecting the washing tank (11) and the cooler (15) among the above-mentioned carbon dioxide recovery paths (111) passes through the distillation tank (14) and only performs heat exchange without mixing of fluids.

[0075] In detail, the high-temperature, high-pressure gaseous carbon dioxide passing through the compressor (13) passes through the washing tank (11) and then the distillation tank (14), releasing heat into gaseous and liquid carbon dioxide inside the distillation tank (14). Then, the liquid carbon dioxide inside the distillation tank (14) vaporizes, increasing the amount of gaseous carbon dioxide. In addition, the gaseous carbon dioxide inside the distillation tank (14), which is reduced in the ventilation process described in Fig. 6, is replenished in the recovery process.

[0076] Meanwhile, the gaseous carbon dioxide passing through the distillation tank (14) after heat exchange is transformed into liquid carbon dioxide through a third heat exchange that releases heat while passing through the cooler (15) and is then finally recovered to the storage tank (12).

[0077] Through this recovery process, the gaseous carbon dioxide in the washing tank (11) is converted into a liquid phase and recovered to the storage tank (12), and the liquid carbon dioxide in the washing tank (11) is recovered to the distillation tank (14).

[0078] Meanwhile, the compressor (13) has its own allowable compression ratio, which can be defined as discharge pressure / suction pressure. In addition, if the compressor (13) is operated under conditions exceeding the allowable compression ratio, the reliability of the compressor (13) may be exceeded, which may result in damage to the compressor or deterioration in performance.

[0079] 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 a small amount of gaseous carbon dioxide remaining inside the washing tub (11) is discharged to the outside through the exhaust path connected to the exhaust port (DP).

[0080] Figure 8 is a drawing showing the process of naturally replenishing carbon dioxide from a bomb to a washing tank.

[0081] Referring to Fig. 8, if it is determined that the level of carbon dioxide remaining in the storage tank (12) is below the set level, a carbon dioxide replenishment process is performed. Whether or not the carbon dioxide replenishment process is performed is determined when laundry is placed inside the washing tank (11) and the pressure in the washing tank (11) becomes vacuum. That is, the internal water level of the storage tank (12) is detected when the pressure in the washing tank (11) becomes vacuum and carbon dioxide can be supplied from the storage tank (12) to the washing tank (11).

[0082] And, if the detected water level is lower than the set water level, carbon dioxide corresponding to the lowered water level is replenished from the outside, and the amount of carbon dioxide corresponding to the calculated water level difference is converted to the pressure of the washing tub (11) at the time of completion of the replenishment and stored in the control unit of the washing machine (10) in the form of a lookup table.

[0083] For example, if the reduced water level is 1 cm and the amount of carbon dioxide corresponding to the reduced water level is supplied to the vacuumed washing tank (11), and the pressure inside the washing tank (11) increases to 10 bar, the pressure increase amount of the washing tank (11) corresponding to the reduced water level of 1 cm is set to 10 bar. Such data can be obtained through multiple experiments, and data on the washing tank pressure for each reduced water level through multiple experiments is stored in the form of a lookup table.

[0084] In detail, in order to replenish carbon dioxide as the carbon dioxide level decreases, a storage container filled with carbon dioxide, i.e., a bomb (16), is connected to the differential pressure supply path (101). Then, the main valve (17) is opened so that carbon dioxide is naturally supplied from the bomb (16) to the washing tank (11) by differential pressure.

[0085] Initially, carbon dioxide is supplied from the bomb (16) to the washing tank (11) due to the pressure difference between the inside of the bomb (16) and the vacuum state of the washing tank (11).

[0086] Meanwhile, as carbon dioxide moves from the bomb (16) to the washing tub (11), the pressure inside the bomb (16) decreases and the pressure inside the washing tub (11) increases, and finally, the pressure inside the bomb (16) and the pressure inside the washing tub (11) become the same, resulting in a state where there is no movement of carbon dioxide.

[0087] When the pressure of the washing tank (11) reaches the replenishment set pressure (or replenishment completion pressure) before reaching a state where there is no movement of carbon dioxide, the main valve (17) is closed to stop the supply of carbon dioxide and allow the washing process to be performed.

[0088] If, at the point where the pressure of the above-mentioned bomb (16) and the pressure of the washing tank (11) become the same, the pressure of the washing tank (11) does not reach the replenishment set pressure, forced replenishment is performed through the compressor.

[0089] The carbon dioxide replenishment process described in Fig. 8 can be defined as natural replenishment.

[0090] Figure 9 is a drawing showing the process of forcibly replenishing carbon dioxide from a bomb to a washing tank.

[0091] Referring to Fig. 9, when the pressure of the bomb (16) and the pressure of the washing tub (11) are the same, the compressor (13) is driven so that the carbon dioxide remaining in the bomb (16) is forcibly sucked in by the compressor (13), compressed, and then supplied to the washing tub (11).

[0092] For this type of forced replenishment, a compression replenishment path (105) branching from a point (P) of the differential pressure replenishment path (104) and connecting the compressor and the washing tank (11) may be added.

[0093] In detail, the branch point (P) can be defined as any point of the differential pressure supplementary flow path (104) connecting the bomb (16) and the washing tank (11).

[0094] In another aspect, when the differential pressure supplementary flow path (104) shares the compression supply flow path (101), the branch point (P) can be defined as any point of the differential pressure supply flow path (101) connecting the storage tank (12) and the washing tank (11).

[0095] And, in any case, the branch point (P) can be described as being formed on the inlet side of the main valve (17) based on the flow of carbon dioxide from the storage tank (12) to the washing tank (11).

[0096] In addition, a switching valve, for example, a three-way valve, may be installed at the branch point (P) so that the flow of carbon dioxide flowing toward the main valve (17) can be switched toward the compressor (13).

[0097] In addition, the outlet of the compression supplementary flow path (105) may be combined with the differential pressure supply flow path (101) at the outlet side of the main valve (17). Alternatively, the washing tank (11) may be provided with a separate supplementary port to which the outlet of the compression supplementary flow path (105) is connected, and a structure in which the outlet of the compression supplementary flow path (105) is connected to the separate supplementary port is also possible.

[0098] In addition, the sub-valve (18) is installed in the compression replenishment path (105) to selectively block the flow of carbon dioxide. That is, when the pressure of the storage tank (11) reaches the replenishment set pressure, the sub-valve (18) is closed, thereby stopping the supply of carbon dioxide from the bomb (16) to the washing tank (11).

[0099] The carbon dioxide replenishment process described in Fig. 9 can be understood as a forced replenishment process.

[0100] In summary, the present invention is characterized in that, in order to replenish carbon dioxide corresponding to the reduced water level inside the storage tank (12), carbon dioxide is first replenished from the cylinder through natural replenishment using a differential pressure phenomenon, and secondly, carbon dioxide is replenished from the cylinder through forced replenishment using a compressor.

[0101] Below, the carbon dioxide replenishment process described above with reference to the drawings will be described in more detail with reference to a flow chart.

[0102] Figure 10 is a flowchart explaining the carbon dioxide replenishment process.

[0103] Referring to Fig. 10, when laundry is put into the washing tub (11) and the pressure inside the washing tub (11) becomes vacuum by the vacuum pump (19), the level of carbon dioxide filled inside the storage tank (12) is detected.

[0104] And, if it is determined that the detected water level is lower than the set water level corresponding to the replenishment limit line, the internal pressure of the washing tank (11) corresponding to the reduced water level is calculated. In other words, the amount of carbon dioxide corresponding to the reduced water level is calculated, and when the calculated carbon dioxide is supplied to the washing tank (11), the internal pressure value of the washing tank (11) is calculated. The reduced water level - carbon dioxide amount - washing tank pressure value is stored in the memory of the washing machine (10) in the form of a lookup table.

[0105] In detail, when the detected carbon dioxide level is determined to be lower than the set level, the carbon dioxide-filled bomb (16) is connected to the differential pressure replenishment path (104) of the washing machine (10). In this state, the carbon dioxide replenishment process begins, and as the first step, the main valve (17) installed in the differential pressure replenishment path (104) is opened (S11). When the main valve (17) is opened, carbon dioxide is directly supplied from the bomb (16) to the washing tub (11), and at this time, it is supplied naturally by the pressure difference without a separate power source (S12). In other words, carbon dioxide is replenished through natural replenishment using the differential pressure phenomenon.

[0106] During the process of replenishing carbon dioxide into the washing tub (11), the internal pressure of the washing tub (11) is detected in real time, and it is determined whether the washing tub pressure has reached the replenishment set pressure (S13). Here, the replenishment set pressure or replenishment completion pressure refers to the internal pressure of the washing tub (11) at the point in time when carbon dioxide corresponding to the reduced water level is supplied to the washing tub (11).

[0107] If the pressure of the washing tank (11) is determined to be higher than the replenishment setting pressure, the main valve (17) is closed (S14), the carbon dioxide replenishment process is terminated, and then the washing process is performed.

[0108] On the other hand, if the pressure of the washing tank (11) is determined to be less than the replenishment setting pressure, it is determined whether the opening time of the main valve (17) has reached the set time (S15). If the opening time of the main valve (17) has not reached the set time, the open state of the main valve (17) is maintained to allow the replenishment of carbon dioxide to continue.

[0109] However, if it is determined that the opening time of the main valve (17) has elapsed the set time, the main valve (17) is closed (S16). If the opening time of the main valve (17) has elapsed the set time while the pressure of the washing tub (11) has not reached the supplementary set pressure, it means that the pressure of the bomb (16) is the same as the pressure of the washing tub (11) while the pressure of the washing tub (11) has not reached the supplementary set pressure, and thus carbon dioxide is not supplied to the washing tub (11) even after the elapse of time.

[0110] Therefore, in this state, the main valve (16) is closed to stop natural replenishment through the differential pressure replenishment path (104) and switch to forced replenishment using the compressor (13).

[0111] Specifically, when the main valve (17) is closed, the sub-valve (18) is opened (S17). Then, the carbon dioxide supply path is switched from a certain point of the differential pressure supplement path (104) to the compression supplement path (105) passing through the compressor (13).

[0112] And, with the opening of the sub valve (18), the compressor (13) is driven (S18), and as a result, the carbon dioxide discharged from the bomb (16) flows along the differential pressure supplementary flow path (104), and from the branch point (P), flows along the compression supplementary flow path (105) connecting the compressor (13) and the washing tub (11) and is supplied to the washing tub (11).

[0113] Meanwhile, after switching from natural replenishment to forced replenishment, it is determined whether the pressure of the washing tank (11) has reached the replenishment setting pressure (S19), and if it is determined that the replenishment setting pressure has been reached, the compressor (13) is stopped (S20) and the sub valve (180) is closed (S21).

[0114] On the other hand, if it is determined that the pressure of the washing tank (11) has not reached the replenishment setting pressure even after switching to forced replenishment, it is determined whether the suction pressure of the compressor (13) is lower than the bomb replacement pressure (S22).

[0115] Even though the replenishment method has been changed from natural replenishment to forced replenishment using a compressor (13), the fact that the pressure of the washing tank (11) does not reach the replenishment setting pressure can be seen as a situation in which the pressure inside the bomb (16) is lower than the allowable suction pressure of the compressor (13), and thus the compressor (13) cannot inhale the carbon dioxide remaining in the bomb (16).

[0116] Accordingly, in this case, the operation of the compressor (13) is stopped (S23), the sub valve (18) is closed, and a notification signal indicating the replacement of the bomb is output (S25), after which the carbon dioxide replenishment process is terminated and the washing process is performed immediately.

[0117] At this stage, rather than allowing subsequent processes to proceed without fully replenishing the reduced carbon dioxide, the washing process is performed with incomplete replenishment of carbon dioxide, and the insufficient carbon dioxide is replenished in the next washing process.

[0118] And, after the bomb replacement notification signal, the replaced bomb (16) can be discarded or reused after being recharged with carbon dioxide.

Claims

1. Washing tub where laundry is put; A storage tank for supplying carbon dioxide to the above washing tank; A distillation tank in which liquid carbon dioxide discharged from the washing tank is collected; A compressor that compresses the gaseous carbon dioxide in the distillation tank and sends it to the washing tank or the storage tank; A cooler that condenses gaseous carbon dioxide discharged from the compressor and supplied to the storage tank into liquid carbon dioxide; A pressure replenishment path connecting the washing tub and the bomb provided to replenish the carbon dioxide reduced through repeated washing processes; A compression supplementary flow path branching from any point of the above differential pressure supplementary flow path and connecting the compressor and the washing tank; and A washing machine including a switching valve provided at a point where the above-mentioned differential pressure supplementary flow path branches.

2. In paragraph 1, A main valve provided at any point of the above pressure supplementary flow path, A washing machine further comprising a sub-valve provided at any point of the above compression replenishment flow path.

3. In paragraph 2, The point where the above pressure supplementary flow branch is A washing machine characterized in that the point corresponds to the inlet side of the main valve based on the flow direction of carbon dioxide flowing along the pressure difference supplementary path.

4. In paragraph 3, The above compression supplementary euro is, The point where the above pressure supplementary flow path branches, the flow path connecting the inlet of the compressor, the outlet of the compressor, and the washing tank, A washing machine characterized in that the sub-valve is provided at any point on the flow path connecting the outlet of the compressor and the washing tub.

5. In paragraph 4, When the main valve is opened, carbon dioxide is supplied from the bomb to the washing tank due to the pressure difference between the bomb and the washing tank. When the pressure of the above-mentioned bomb and the above-mentioned washing tank becomes equal, the above-mentioned main valve is closed, A washing machine characterized in that the above switching valve operates to switch the flow direction to the compression replenishment path.

6. In paragraph 5, When the flow direction of the above carbon dioxide is switched to the above compression supplementary path, A washing machine characterized in that the compressor operates and the sub-valve opens, so that carbon dioxide is forcibly supplied from the bomb to the washing tub.

7. In any one of paragraphs 1 to 6, A washing machine further comprising a differential pressure supply path connecting the storage tank and the washing tank.

8. In paragraph 7, A part of the above pressure relief flow path shares the above pressure relief supply flow path, so that the outlet of the above pressure relief flow path is the same as the outlet of the above pressure relief supply flow path, A washing machine characterized in that the main valve is provided on the differential pressure supply path.

9. In paragraph 7, The above differential pressure supplementary flow path and the above differential pressure supply flow path form independent flow paths, A washing machine characterized in that the outlet of the pressure differential supplementary flow path and the outlet of the pressure differential supply flow path are respectively connected to different ports formed in the washing tub.

10. In paragraph 1, The outlet of the above compression supplementary flow is, A washing machine characterized in that the pressure relief valve is joined at any point of the above pressure relief valve.

11. In paragraph 10, The outlet of the above pressure relief flow is, A washing machine characterized in that the carbon dioxide flowing along the differential pressure supplementary flow path is combined at a point of the differential pressure supplementary flow path corresponding to the outlet side of the main valve, based on the flow direction of the carbon dioxide flowing along the differential pressure supplementary flow path.

12. In paragraph 1, A washing machine characterized in that the outlet of the compression supplementary flow path and the outlet of the differential pressure supplementary flow path are respectively connected to different ports formed in the washing tub.

13. The step where laundry is placed inside the washing tub and the washing tub door is closed; A step in which the pressure inside the washing tank is lowered to a vacuum state; A step of supplying carbon dioxide from a storage tank to the washing tank; and Includes a step in which the washing process is performed, When the inside of the washing machine is in a vacuum state, A step of detecting the level of liquid carbon dioxide inside the storage tank; and If the detected water level is lower than the set water level, a step of performing a carbon dioxide replenishment process for replenishing carbon dioxide to the washing tank from a separately connected bomb is included. When the above carbon dioxide replenishment process begins, A control method for a washing machine, comprising a step of opening a main valve installed on a pressure difference replenishment path connecting the bomb and the washing tub, and performing a natural replenishment process in which carbon dioxide naturally flows from the bomb to the washing tub due to a pressure difference between the bomb and the washing tub, When the pressure of the above-mentioned drum becomes equal to the pressure of the above-mentioned drum before the pressure of the above-mentioned drum reaches the replenishment set pressure, The above main valve is closed, thereby stopping the natural replenishment process; and A control method for a washing machine, comprising a step of performing a forced replenishment process using the compressor.

14. In paragraph 13, The above supplementary setting pressure is, A control method for a washing machine, characterized in that the pressure inside the washing tub is detected when an amount of carbon dioxide corresponding to the reduced water level is supplied to the washing tub.

15. In paragraph 14, The supply of carbon dioxide through the above forced replenishment process is It is formed along a forced replenishment path connecting the above-mentioned bomb, the above-mentioned compressor, and the above-mentioned washing tank, A control method for a washing machine, characterized in that it is selectively performed by opening and closing a sub-valve provided on a forced replenishment path connecting the compressor and the washing tub.

16. In paragraph 15, When the above forced replenishment process begins, A control method for a washing machine, characterized in that the compressor operates with the opening of the sub-valve, so that carbon dioxide inside the bomb is sucked into the compressor and then compressed and supplied to the washing tub.

17. In paragraph 16, When the pressure of the above washing tank reaches the above supplementary setting pressure, The above compressor stops, The above sub-valve is closed, A control method for a washing machine, characterized in that the washing process is performed continuously.

18. In paragraph 16, If the suction pressure of the compressor decreases below the replacement pressure of the bomb before the pressure of the washing tank reaches the supplementary set pressure, The above compressor stops, A control method for a washing machine, characterized in that the above sub-valve is closed.

19. In paragraph 18, A control method for a washing machine, characterized in that a bomb replacement alarm is generated simultaneously or sequentially with the closing of the above sub-valve.

20. In paragraph 19, A control method for a washing machine, characterized in that the washing process is continuously performed after the sub-valve is closed or the bomb replacement alarm is generated.

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