Washing machine with wetting water and steam control

A washing machine in which the poor heat-resistance laundry is sufficiently wet so that a plurality of water curtain layers are formed at the laundry, thereby preventing the laundry from being stained and damaged when the laundry contacts the steam. According to the present invention, cold water is supplied simultaneously with injection of the steam so that the real temperature of the steam contacting the surfaces of the laundry is lowered, thereby preventing the laundry from being stained and damaged when the laundry contacts the steam.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No. 2004-679, filed on Jan. 6, 2004, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a washing machine, and more particularly to a washing machine that is capable of washing delicate cloths with steam. The present invention also relates to a method of controlling such a washing machine.

2. Description of the Related Art

For a conventional washing machine, a washing process is set on the basis of materials of the laundry. The washing temperature and the number of rinsing times are also set on the basis of materials of the laundry. Water is heated by a heater disposed in a water tub of the washing machine so that the heated water is used as wash water.

After a prescribed amount of water is supplied to the conventional washing machine, the washing machine heats water supplied into the washing tub using the heater until the temperature of the water reaches a prescribed washing temperature. As the reverse turn of the washing tub is repeated, a detergent supplied along with the water is dissolved, whereby the washing operation is carried out.

The conventional washing machine requires an installation space for the heater, which is provided at the lower part of the washing tub for heating water. As a result, the size of the conventional washing machine is increased, which requires a corresponding increase in water. Also, a large amount of water is necessary to dissolve the detergent, which leads to further consumption of electric energy and increase of the washing time.

To this end, a washing machine has been developed that is capable of washing the laundry with steam to reduce the amount of water to be used. When hot steam contacts the laundry, however, the laundry may be damaged due to the high temperature of the steam. Furthermore, when the hot steam contacts the surfaces of the poor heat-resistant laundry, such as wool, silk, or delicate clothes, the laundry is easily damaged. When the hot steam contacts the detergent applied to the clothes, on the other hand, the detergent sticks to the clothes. As a result, the washed clothes are stained. Therefore, it is required that the washing process be carried out at a suitable washing temperature when the laundry is to be washed using steam.

SUMMARY OF THE INVENTION

Therefore, an object of the invention is to provide a washing machine that is capable of preventing the laundry from being stained and damaged due to hot steam when the laundry is washed using the steam, and further preventing the poor heat-resistant laundry from being damaged due to the hot steam when the laundry is washed using the steam.

Another object of the invention is to provide a method of controlling such a washing machine.

In accordance with one aspect, the present invention provides a washing machine comprising: a rotary drum for accommodating the laundry; a water supply unit; a steam generating unit; and a controller for controlling a washing operation, wherein when the laundry is washed with steam, the controller sets the amount of wetting water necessary to wet the laundry, controls the water supply unit so that the set amount of wetting water is supplied, and controls the steam generating unit so that the laundry is washed with the generated steam.

In accordance with another aspect, the present invention provides a washing machine comprising: a rotary drum for accommodating the laundry; a water supply unit; a steam generating unit; and a controller for controlling a washing operation, wherein, when the laundry is washed with steam, the controller sets the amount of wetting water necessary to wet the laundry, controls the water supply unit so that the set amount of wetting water is supplied, and, if the laundry has poor heat resistance, controls the steam generating unit and the water supply unit so that steam and water are simultaneously supplied into the rotary drum.

In accordance with another aspect, the present invention provides a washing machine comprising: a rotary drum for accommodating the laundry; a water supply unit; a steam generating unit; and a controller for controlling a washing operation, wherein, when the laundry, having poor heat resistance, is washed with steam, the controller resets the initial amount of wetting water necessary to wet the laundry, controls the water supply unit so that the reset amount of wetting water is supplied, and controls the steam generating unit and the water supply unit so that steam and water are simultaneously supplied into the rotary drum.

In accordance with another aspect, the present invention provides a method of controlling a washing machine that performs a washing operation using steam, comprising the steps of: setting the amount of wetting water necessary to wet the laundry in a rotary drum when a steam washing operation is selected; supplying the set amount of wetting water; and supplying steam to the wet laundry.

In accordance with another aspect, the present invention provides a method of controlling a washing machine that performs a washing operation using steam, comprising the steps of: setting the amount of wetting water necessary to wet the laundry in a rotary drum when a steam washing operation is selected; supplying the set amount of wetting water; and, when the laundry has poor heat resistance, simultaneously supplying steam and water into the rotary drum having the wet laundry accommodated therein.

In accordance with still another aspect, the present invention provides a method of controlling a washing machine that performs a washing operation using steam, comprising the steps of: when the laundry, having poor heat resistance, is washed with steam, resetting the initial amount of wetting water necessary to wet the laundry in a rotary drum; supplying the reset amount of water; and simultaneously supplying steam and water into the rotary drum having the wet laundry accommodated therein.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

FIG. 1is a view illustrating the configuration of a washing machine according to an embodiment of the present invention, for example, a drum washing machine with a steam-generating unit equipped thereto.

The drum washing machine according to the present invention includes: a first water supply pipe12for supplying water introduced from an external water pipe2to a water tub10; a third water supply pipe13for supplying the water into a rotary drum11; and a second water supply pipe14for supplying the water to a heating tank31of a steam-generating unit30.

The first water supply pipe12is provided with a first water supply valve3and a detergent storage box16. The detergent storage box16serves to store a powder detergent. The water supplied through the first water supply valve3passes through the detergent storage box16, and is then discharged along with the powder detergent through an outlet pipe16aso that the water is introduced into the water tub10.

The third water supply pipe13is provided with a third water supply valve5for supplying the water to the rotary drum11. At the end of the third water supply pipe13is disposed an injection nozzle13afor injecting the water into the rotary drum11.

At the bottom of the water tub10is disposed a drain pipe17. In the drain pipe17is mounted a pump motor18for pumping out the water and the detergent at the bottom of the water tub10, and a drain valve19. Between the pump motor18and the drain valve19is disposed a connection pipe20, which is branched from the drain pipe17. One end of the connection pipe20is connected to the drain pipe, and the other end of the connection pipe20is extended to the inlet of the rotary drum11. In the middle of the connection pipe20is formed a cylindrical detergent dissolving space20bhaving a diameter larger than that of the connection pipe20. At the end of the connection pipe20is provided an injection nozzle20afor injecting the detergent solution into the rotary drum11.

At the connection pipe20is disposed a backward-flow preventing valve21. When the drain valve19is opened while the flow channel is intercepted by the backward-flow preventing valve21, the water pumped by means of the pump motor18is discharged to the outside without flowing backward to the connection pipe above the backward-flow preventing valve21. When the drain valve19is closed while the flow channel is not intercepted by means of the backward-flow preventing valve21, the water pumped by means of the pump motor18is introduced into the connection pipe above the backward-flow preventing valve21.

To one side of the rotary drum11is mounted a drum motor23, which is rotatable in a forward or reverse direction. The rotary drum11can be alternately rotated in one direction and in the opposite direction by means of the drum motor23.

The steam-generating unit30, which heats the water supplied through a second water supply valve4, is connected to the second water supply pipe14. The steam-generating unit30is provided with the heating tank31. In the heating tank are mounted a heater for heating water to generate steam, a level sensor for detecting the level of the water, and a temperature sensor for detecting the temperature of the water. At the outlet of the steam-generating unit30is provided a steam supply valve32.

FIG. 2is a block diagram applied to the washing machine shown inFIG. 1.

The washing machine of the present invention further comprises a controller60for controlling the overall operation of the washing machine. The controller60includes a microcomputer61and a storage unit62. The storage unit62stores information for washing the laundry with steam, such as wash water level, washing time, etc.

To the inlets of the microcomputer61are connected an input unit63for setting input instructions, which are set by a user, a first level sensor64mounted at a prescribed position of the water tub for detecting the level of water filled in the water tub, a first temperature sensor65mounted at a prescribed position of the water tub for detecting the temperature of water filled in the water tub, a second level sensor34mounted at a prescribed position of the heating tank31for detecting the level of water filled in the heating tank, and a second temperature sensor35mounted at a prescribed position of the heating tank for detecting the temperature of water filled in the heating tank.

To the outputs of the microcomputer61are connected a water supply valve driving unit66for driving the first to third water supply valves3to5, the steam supply valve32, the drain valve19, and the backward-flow preventing valve21, a motor driving unit67for driving the drum motor23and the pump motor18, and a heater driving unit68for driving a steam-generating heater33.

The microcomputer61controls the overall operation of washing the laundry with steam.

When the laundry is washed with steam in accordance with to a first embodiment of the present invention, the total amount of the wash water required to wash the laundry is not supplied all at once. The water supply operations, which are applied to the present invention, are divided into a first water supply operation ((A) ofFIG. 3) for supplying simply water and a second water supply operation ((B) ofFIG. 3) for supplying water during washing with steam. Specifically, the first water supply operation is a primary water supply operation for supplying water to a first wash water level so that the laundry is wet when the washing operation is initiated, as shown inFIG. 3. On the other hand, the second water supply operation is a secondary water supply operation for supplying water to a second wash water level so that the water is supplemented while the laundry is washed with steam, as shown inFIG. 3. The first and second wash water levels are previously set on the basis of the weights of the laundry.

Furthermore, the first wash water level for the primary water supply is reset ((B) ofFIG. 3) when the poor heat-resistance, such as wool, silk, or delicate clothes, is to be washed. At this time, the reset first wash water level is set larger than the previously set amount of water so that the poor heat-resistance laundry is sufficiently wet. Especially for the laundry with low heat-resistance, it is necessary that the reset water level be set much higher. The reset information is stored in the storage unit62. As the first wash water level is reset, the amount of wash water through the first water supply operation is increased. Consequently, a plurality of water curtain layers are formed at the laundry, thereby preventing the laundry from being stained and damaged when the laundry contacts the hot steam.

FIG. 4is a flow chart illustrating a method of controlling a washing machine in accordance with a first embodiment of the present invention, andFIGS. 5A to 5Eare schematic views illustrating respective washing steps in accordance with the control method shown inFIG. 4especially when the laundry is washed using steam.

After the laundry to be washed is put in the rotary drum11and a door, which is not shown, is closed, the amount, the material, and the washing temperature of the laundry are set on the basis of setting instructions of a user, which are inputted from the input unit63(S101). The microcomputer61determines whether it is a washing course for washing the laundry with steam (S103). If it is not determined that the laundry is to be washed with the steam, for example, if it is another washing course for washing the laundry with cold water and a detergent, the washing operation is carried out on the basis of the corresponding washing course (S104).

If it is determined that the laundry is to be washed with the steam at Step S103, the first wash water level for the primary water supply is set by means of the microcomputer61. The first wash water level A is set on the basis of the amount of the laundry set at Step S101(S105). The information of the first wash water level A on the basis of the amount of the laundry is previously stored in the storage unit62.

The microcomputer61at Step S106determines whether the laundry includes delicate clothes. When it is determined that the laundry includes the delicate clothes, the microcomputer61resets the first wash water level at Step S107. The reset first wash water level B is set higher than the previously set first wash water level A so that the delicate clothes are sufficiently wet (S107).

The microcomputer61controls the water supply driving unit66so that the third water supply valve5is opened. Consequently, water introduced from the external water pipe2is supplied into the rotary drum through the injection nozzle13aso that the laundry is wet. At the same time, the microcomputer61controls the water supply valve driving unit66so that the first water supply valve3is opened. Consequently, a powder detergent is supplied into the water tub along with the water introduced through the first water supply pipe12. The microcomputer61also controls the motor driving unit67so that the pump motor18is driven. Consequently, the water and the powder detergent are supplied into the cylindrical detergent dissolving space20b, where the water and the powder detergent are mixed to obtain a detergent solution. After the detergent solution is obtained, the motor driving unit67is controlled by means of the microcomputer61so that the pump motor18is driven. As a result, the detergent solution in the detergent dissolving space is injected into the rotary drum through the injection nozzle20aso that the detergent solution is sprayed onto the laundry. At this time, the motor driving unit67is controlled by means of the microcomputer61so that the rotary drum is driven in the reverse direction (S109) (Refer toFIG. 5A).

While the water is supplied, the level of the water in the water tub is detected by means of the first level sensor64. The microcomputer61determines whether the detected level is the reset first wash water level B (S113). If it is determined that the detected level is not the reset first wash water level B, the rotary drum is driven in the reverse direction as shown inFIG. 5Bso that water is continuously supplied (S114).

If it is determined that the detected level is the reset first wash water level B in Step S113, the valve driving unit66is controlled by means of the microcomputer61so that the water supply is stopped as shown inFIG. 5C(S115), and the rotary drum is driven in the reverse direction for a prescribed period of time (S117).

Consequently, the delicate clothes are sufficiently wetted. At this time, the microcomputer61controls the valve driving unit66to open the second water supply valve4so that a prescribed amount of water is filled in the heating tank31. The second water supply valve4is closed based on the basis of the water level detected by means of the second level sensor34. At the same time, the microcomputer61controls the heater driving unit68so that the heater33is driven. As the heater is driven, the water in the heating tank31is heated. When the water is heated and thus steam is generated in the heating tank, the microcomputer61controls the valve driving unit66so that the steam supply valve32is opened. As a result, the hot steam generated in the heating tank is injected into the rotary drum through the injection nozzle14aof the second water supply pipe14. Also, the microcomputer61controls the motor driving unit67so that the rotary drum is driven in the reverse direction. At this time, the sufficiently wet delicate clothes are not stained or damaged although the clothes contact the hot steam, whereby the steam washing operation is satisfactorily carried out (S119) (Refer toFIG. 5D).

While the laundry is washed with the steam, the water level in the water tub is detected by means of the first level sensor64(S121). It is determined by means of the microcomputer61whether the detected level is the second wash water level C for steam washing (S123). If it is determined that the detected level is not the second wash water level C, the rotary drum is driven in the reverse direction as shown inFIG. 5Eso that a prescribed amount of water is supplemented (S124), and it is returned to Step S119so that the steam washing operation is carried out.

If it is determined that the detected level is the second wash water level C in Step S123, the water supply is stopped, and it is determined by means of the microcomputer61whether the steam washing operation is to be completed (S125). If it is determined that the steam washing operation is not to be completed, it is retuned to Step S119so that the steam washing operation is carried out.

If it is determined that the steam washing operation is to be completed in Step S125, prescribed rinsing and dewatering operations are carried out (S127).

According to a second embodiment of the present invention, cold water is supplied simultaneously when the steam is injected so that the temperature of the steam contacting the surface of the poor heat-resistant laundry, such as wool, silk, or delicate clothes, is lowered, thereby preventing the laundry from being stained and damaged when the laundry contacts the steam.

FIGS. 6A and 6Bare flow charts illustrating a method of controlling a washing machine in accordance with a second embodiment of the present invention, andFIGS. 7A to 7Eare schematic views illustrating respective washing steps in accordance with the control method shown inFIGS. 6A and 6Bespecially when the laundry is washed using steam.

After the laundry to be washed is put in the rotary drum11and a door, which is not shown, is closed, the amount, the material, and the washing temperature of the laundry are set on the basis of setting instructions of a user, which are inputted from the input unit63(S201). The microcomputer61determines whether it is a washing course for washing the laundry with steam (S203). If it is not determined that the laundry is to be washed with the steam, for example, if it is another washing course for washing the laundry with cold water and a detergent, the washing operation is carried out on the basis of the corresponding washing course (S204).

If it is determined that the laundry is to be washed with the steam at Step S203, the first wash water level for the primary water supply is set by means of the microcomputer61. The first wash water level A is set on the basis of the amount of the laundry set at Step S201(S205). The information of the first wash water level A on the basis of the amount of the laundry is previously stored in the storage unit62.

The microcomputer61controls the water supply valve driving unit66so that the third water supply valve5is opened. Consequently, water introduced from the external water pipe2is supplied into the rotary drum through the injection nozzle13aso that the laundry is wetted. At the same time, the microcomputer61controls the water supply valve driving unit66so that the first water supply valve3is opened. Consequently, a powder detergent is supplied into the water tub along with the water introduced through the first water supply pipe12. The microcomputer61also controls the motor driving unit67so that the pump motor18is driven. Consequently, the water and the powder detergent are supplied into the cylindrical detergent dissolving space20b, where the water and the powder detergent are mixed to obtain a detergent solution. After the detergent solution is obtained, the motor driving unit67is controlled by means of the microcomputer61so that the pump motor18is driven. As a result, the detergent solution in the detergent dissolving space is injected into the rotary drum through the injection nozzle20aso that the detergent solution is sprayed onto the laundry. At this time, the motor driving unit67is controlled by the microcomputer61so that the rotary drum is driven in the reverse direction (S207) (Refer toFIG. 7A).

While the water is supplied, the level of the water in the water tub is detected by the first level sensor64. The microcomputer61determines whether the detected level is the first wash water level A (S211). If it is determined that the detected level is not the first wash water level A, the rotary drum is driven in the reverse direction as shown inFIG. 7Bso that water is continuously supplied (S212).

If it is determined that the detected level is the first wash water level A in Step S212, the valve driving unit66is controlled by means of the microcomputer61so that the water supply is stopped as shown inFIG. 7C(S213), and the rotary drum is driven in alternating directions for a prescribed period of time (S215).

The microcomputer61controls the valve driving unit66to open the second water supply valve4so that a prescribed amount of water is filled in the heating tank31. The second water supply valve4is closed on the basis of the water level detected by means of the second level sensor34. At the same time, the microcomputer61controls the heater driving unit68so that the heater33is driven. As the heater is driven, the water in the heating tank is heated. When the water is heated and thus steam is generated in the heating tank, the microcomputer61controls the valve driving unit66so that the steam supply valve32is opened.

When it is determined that the laundry includes the delicate clothes, the valve driving unit66is controlled by means of the microcomputer61so that the third water supply valve5is opened.

As a result, the hot steam is injected into the rotary drum through the injection nozzle14aof the second water supply pipe14. At the same time, cold water is supplied into the rotary drum through the injection nozzle13aof the third water supply pipe13. Also, the microcomputer61controls the motor driving unit67so that the rotary drum is driven in the reverse direction. At this time, the hot steam and cold water are simultaneously injected into the rotary drum Consequently, the delicate clothes are not stained or damaged although the clothes contact the hot steam, whereby the steam washing operation is satisfactorily carried out (S207) (Refer toFIG. 7D).

When it is determined that the laundry does not include the delicate clothes at Step S216, the washing operation proceeds to Step S218where steam is injected into the drum and the drum is driven in the reverse direction so that the laundry is washed.

While the laundry is washed, the temperature of the water is detected by means of the first temperature sensor65(S219). It is determined by means of the microcomputer61whether the detected temperature is below the steam washing temperature for steam washing (S221). If it is determined that the detected temperature is not below the steam washing temperature for steam washing, it is returned to Step S217.

If it is determined that the detected temperature is below the steam washing temperature for steam washing at Step S221, the water level in the water tub is detected by means of the first level sensor64(S223). It is determined by means of the microcomputer61whether the detected level is the second wash water level C for steam washing (S225). If it is determined that the detected level is not the second wash water level C, the rotary drum is driven in the reverse direction as shown inFIG. 7Eso that a prescribed amount of water is supplemented (S256), and it is returned to Step S217so that the steam washing operation is carried out.

If it is determined that the detected level is the second wash water level C in Step S225, the water supply is stopped, and it is determined by means of the microcomputer61whether the steam washing operation is to be completed (S227). If it is determined that the steam washing operation is not to be completed, it is returned to Step S217so that the steam washing operation is carried out.

If it is determined that the steam washing operation is to be completed in Step S227, prescribed rinsing and dewatering operations are carried out (S229).

As apparent from the above description, the amount of wetting water to be supplied is set on the basis of the materials of the laundry according to the first embodiment of the present invention, thereby eliminating bad effects caused when the laundry is washed with steam. According to the second embodiment of the present invention, steam and water are simultaneously supplied into a rotary drum so that the real temperature of the steam contacting the surfaces of the laundry is lowered, thereby eliminating bad effects caused when the laundry is washed with the steam. Although not described in the above-mentioned embodiments, it is possible that the construction for setting the amount of wetting water to be supplied based on the basis of the materials of the laundry as in the first embodiment and the construction for simultaneously supplying the steam and the water as in the second embodiment are simultaneously applied to a washing machine, whereby the poor heat-resistant laundry is satisfactorily washed with the steam.

When the laundry is washed with steam, a predetermined amount of wetting water is supplied to the laundry, before the steam is supplied, so that the laundry is wet with the wetting water in accordance with the first embodiment of the present invention, Consequently, the laundry is not damaged due to the steam having a high temperature. Furthermore, when the poor heat-resistant laundry, such as wool, silk, or delicate clothes, is to be washed with steam, the amount of wetting water is increased so that the steam washing operation is carried out while the laundry is sufficiently wet, therby preventing the laundry from being stained and damaged when the laundry contacts the steam. When the poor heat-resistant laundry, such as wool, silk, or delicate clothes, is to be washed with steam, steam and cold water are simultaneously injected into the rotary drum in accordance with the second embodiment of the present invention, thereby preventing the laundry from being stained and damaged when the laundry contacts the steam.