Patent Description:
The water purifier may filter water and may supply water to a user.

The water purifier may include a reverse osmosis filter to filter water. The reverse osmosis filter may include a reverse osmosis membrane for filtering water such that the reverse osmosis filter may be partitioned into a non-filtration side and a filtration side.

Some of water flowing into the non-filtration side of the reverse osmosis filter may be filtered while passing through the reverse osmosis membrane, and the remaining water may not pass through the reverse osmosis membrane. Water filtered while passing through the reverse osmosis membrane may flow to the filtration side, may flow through a connection line connected to the filtration side and may be discharged through a water outlet member connected to the connection line. The residential water, which is water not passing through the reverse osmosis membrane, may flow through the residential water line connected to the non-filtration side and may be drained.

Meanwhile, after the filtration of water in the reverse osmosis filter is in progress or immediately after the filtration of water is stopped, there may be a difference in total dissolved solid (TDS) concentrations of the non-filtration side and the filtration side of the reverse osmosis filter. That is, the concentration of TDS on the non-filtration side of the reverse osmosis filter may be higher than the concentration of TDS on the filtration side. However, when water filtration is not performed for more than a predetermined time after the water filtration in the reverse osmosis filter stops, water on the non-filtration side may pass through the reverse osmosis membrane due to the difference in concentration of TDSs between the non-filtration side and the filtration side of the reverse osmosis filter and may flow to the filtration side. Accordingly, the concentration of TDSs of the non-filtration side and the filtration side of the reverse osmosis filter may become the same, which may be known as a creepage phenomenon.

After the filtration of water in the reverse osmosis filter is not performed for more than a predetermined time, the filtration of water may be performed in the reverse osmosis filter, and the initially discharged water may have a high concentration of TDS due to the creepage phenomenon described above. Accordingly, after filtration of water is not performed in the reverse osmosis filter for a predetermined time or more, when the water is filtered in the reverse osmosis filter, water having a high concentration of TDS may be initially supplied to a user.

<CIT> discloses a water purifying machine. The machine comprises a reverse osmosis membrane filter, a pressure barrel, a water purifying bypass way and a flushing solenoid valve; the water purifying bypass way is provided with a first solenoid valve and a first one-way valve, one end of the water purifying bypass way is connected with an outlet of the pressure barrel, and the other end is connected with a raw-water inlet of the reverse osmosis membrane filter; and the flushing solenoid valve is arranged on a pipeline of a wastewater outlet of the reverse osmosis membrane filter.

The present disclosure has been made in recognition of at least one of the needs or problems occurring in the prior art as described above.

One aspect of the purpose of the present disclosure is to provide water having a relatively low concentration of TDS to a user.

Another aspect of the present disclosure is to flush the filtration side of a reverse osmosis filter before water filtered by the filter unit is discharged through a water outlet member, and to flush the non-filtration side of the reverse osmosis filter after the water filtered by the filter unit is discharged through the water outlet member.

A method of controlling a water purifier according to the present invention addressing the above mentioned problems is subject of the independent claim <NUM>. Refinements to said method are subject of the dependent claims.

A corresponding water purifier according to an embodiment for implementing at least one of the problems may include the following features.

The water purifier according to an embodiment of the present disclosure includes a filter unit including a reverse osmosis filter; a water outlet unit including a water outlet member connected to the filter unit; and a control unit for discharging water filtered by the filter unit to the outside through the water outlet member, wherein the reverse osmosis filter includes a reverse osmosis membrane for filtering water such that the reverse osmosis filter is partitioned into a non-filtration side and a filtration side, and wherein the control unit allows the filtration side to be flushed before water filtered by the filter unit is discharged through the water outlet member, and the control unit allows the non-filtration side to be flushed after water filtered by the filter unit is discharged through the water outlet member.

The control unit may allow the filtration side to be flushed for a predetermined time.

The control unit may allow the non-filtration side to be flushed in response to the time for which water filtered by the filter unit is discharged through the water outlet member or the amount of the water.

The non-filtration side may be connected to a water inlet valve connected to the control unit, a water inlet line including a water inlet pump, and a residential water line including a residential water valve, and the filtration side may include a water outlet valve connected to the control unit and may be connected to the water outlet member.

The water outlet line may be connected to a first flushing line including a first flushing valve connected to the control unit, and the residential water line may be connected to a second flushing line including a second flushing valve connected to the control unit.

The control unit may open the water inlet valve, and while the control unit drives the water pump, the control unit may open the first flushing valve for a predetermined time, and thereafter, the control unit may close the first flushing valve and may open the water outlet valve.

The control unit may open the first flushing valve for at least <NUM> seconds.

The control unit may close the water outlet valve and then may open the second flushing valve.

The control unit may open the second flushing valve in response to the time for which the water outlet valve is opened or the amount of water discharged through the water outlet member and then may close the second flushing valve.

The control unit may close the second flushing valve, and thereafter, the control unit may close the water inlet valve and may stop the driving of the water inlet pump.

The residential water line may include a shut-off valve connected to the control unit, and the control unit closes the shut-off valve when the first flushing valve is opened.

As described above, according to an embodiment of the present disclosure, the filtration side of the reverse osmosis filter is flushed before the water filtered by the filter unit is discharged through the water outlet member, and the water filtered by the filter unit is discharged through the water outlet member. The non-filtration side of the reverse osmosis filter may be flushed after being discharged through the water outlet member.

Also, according to an embodiment of the present disclosure, water having a relatively low concentration of TDS may be provided to a user.

To help the understanding of the features of the present disclosure as described above, it will be described in greater detail below with respect to the water purifier related to the embodiment of the present disclosure.

The embodiments described below will be described based on the most suitable embodiments for understanding the technical features of the present disclosure, and the technical features of the present disclosure are not limited to the described embodiments, and the present disclosure may be implemented as in the embodiments described below. Accordingly, various modifications of the present disclosure may be implemented within the technical scope of the present disclosure through the embodiments described below, and these modified embodiments will fall within the technical scope of the present disclosure. Also, as for the reference characters in the accompanying drawings to help the understanding of the embodiments to be described below, related components among components performing the same operation in each embodiment are indicated by the same or extended reference characters.

Hereinafter, an embodiment of the water purifier according to the present disclosure will be described with reference to <FIG>.

<FIG> is a diagram illustrating a water purifier according to the present disclosure. <FIG> are diagrams illustrating an embodiment of operation of a water purifier according to the present disclosure.

Also, <FIG> is a graph of concentration of TDS of water flowing in a portion of a water outlet line adjacent to a reverse osmosis filter over time when water is not filtered for <NUM> minutes and <NUM> minutes in the reverse osmosis filter of a conventional water purifier, and is filtered in the reverse osmosis filter thereafter.

<FIG> is a graph of a TDS removal rate from a first cup to a fifth cup in the case in which water discharged to the outside through a water outlet member of a water outlet unit is continuously received several times with a cup of the same capacity in a conventional water purifier to which flushing of the filtration side of the reverse osmosis filter is not applied, and a water purifier according to the present disclosure to which flushing of the filtration side of the reverse osmosis filter is applied.

Also, <FIG> is a graph of changes in concentration of TDS on the non-filtration side of the reverse osmosis filter over time when water filtered by the reverse osmosis filter is discharged through the water outlet member of the water outlet unit in the water purifier according to the present disclosure, and changes in concentration of TDS on the non-filtration side of the reverse osmosis filter over time when the non-filtration side of the reverse osmosis filter after is flushed after water is discharged through the water outlet member.

An embodiment of the water purifier <NUM> according to the present disclosure may include a filter unit <NUM>, a water outlet unit <NUM>, and a control unit <NUM>.

The filter unit <NUM> may include a reverse osmosis filter <NUM>. As illustrated in <FIG>, the reverse osmosis filter <NUM> may include a reverse osmosis membrane MB for filtering water. The reverse osmosis filter <NUM> may be partitioned into a non-filtration side <NUM> and a filtration side <NUM> by the reverse osmosis membrane MB.

The non-filtration side <NUM> of the reverse osmosis filter <NUM> may be connected to the water inlet line LI as illustrated in <FIG>. The water inlet line LI may include a water inlet valve VI and a water inlet pump PI. The water inlet line LI may be connected to a water supply source (not illustrated) such as tap water. Accordingly, when the water inlet valve VI is opened and the water inlet pump PI is driven, water from the water supply source may flow through the water inlet line LI and may flow into the filtration side <NUM> of the reverse osmosis filter <NUM> as illustrated in <FIG>. As illustrated in <FIG> and <FIG>, some of the water flowing into the non-filtration side <NUM> of the reverse osmosis filter <NUM> may be filtered while passing through the reverse osmosis membrane MB and may flow to the filtration side <NUM>, and the remaining water may not pass through the reverse osmosis membrane MB. Meanwhile, a second flushing valve VF2 may be provided in a second flushing line LF2 connected to a residential water line LL, described later, connected to the non-filtration side <NUM> of the reverse osmosis filter <NUM>. When the second flushing valve VF2 is opened, a predetermined filtration pressure may not be formed on the non-filtration side <NUM> of the reverse osmosis filter <NUM>. Accordingly, the entire water flowing into the non-filtration side <NUM> of the reverse osmosis filter <NUM> may not pass through the reverse osmosis membrane MB and may flow into the residential water line LL as illustrated in FIG. LF2, and may flow to the second flushing line LF2.

The non-filtration side <NUM> of the reverse osmosis filter <NUM> may also be connected to the residential water line LL as illustrated in <FIG>. The residential water valve VL may be provided in the residential water line LL. The residential water valve VL may allow a predetermined filtration pressure to be formed on the non-filtration side <NUM> of the reverse osmosis filter <NUM>. Accordingly, water flowing into the non-filtration side <NUM> of the reverse osmosis filter <NUM> may be filtered while passing through the reverse osmosis membrane MB and may flow to the filtration side <NUM>. Also, as illustrated in <FIG> and <FIG>, the residential water valve VL may allow the residential water, which may be not be filtered as the water has not been able to pass through the reverse osmosis membrane MB of the reverse osmosis filter <NUM>, to be drained through the residential water line LL. The configuration of the living water valve VL is not particularly limited, and any component which may allow a predetermined filtration pressure to be formed on the non-filtration side <NUM> of the reverse osmosis filter <NUM> and may allow the residential water, which may be not be filtered as the water has not been able to pass through the reverse osmosis membrane MB of the reverse osmosis filter <NUM>, to be drained may be used.

As illustrated in <FIG>, the filtration side <NUM> of the reverse osmosis filter <NUM> may be connected to a water outlet line LO. Water flowing into the non-filtration side <NUM> of the reverse osmosis filter <NUM>, filtered while passing through the reverse osmosis membrane MB, and flowing to the filtration side <NUM> may flow into the water outlet line LO as illustrated in <FIG> and <FIG>. As illustrated in <FIG>, when the first flushing valve VF1 provided in a first flushing line LF1, described later, connected to the water outlet line LO is opened, water flowing into the water outlet line LO and filtered by the reverse osmosis filter <NUM> may flow to the first flushing line LF1. Accordingly, the filtration side <NUM> of the reverse osmosis filter <NUM> may be flushed by the water filtered while passing through the reverse osmosis membrane MB. The water outlet line LO may be connected to a water outlet member <NUM> included in the water outlet unit <NUM> described later. Also, the water outlet line LO may include a water outlet valve VO. Accordingly, when the water outlet valve VO is opened, the water flowing into the water outlet line LO may flow to the water outlet member <NUM> through the water outlet line LO and may flow to the outside through the water outlet member <NUM> as illustrated in <FIG>.

Meanwhile, as illustrated in <FIG>, a first flushing line LF1 may be connected to the water outlet line LO. A first flushing valve VF1 may be provided in the first flushing line LF1. When the first flushing valve VF1 is opened, water filtered while passing through the reverse osmosis membrane MB of the reverse osmosis filter <NUM>, flowing to the filtration side <NUM>, and flowing into the water outlet line LO may flow to the first flushing line LF1 as illustrated in <FIG>. Accordingly, the filtration side <NUM> of the reverse osmosis filter <NUM> may be flushed by the water filtered while passing through the reverse osmosis membrane MB. A check valve VC may be provided in the first flushing line LF1. Water may flow from the filtration side <NUM> of the reverse osmosis filter <NUM> to the first flushing line LF1 by the check valve VC, but may not flow from the first flushing line LF1 to the filtration side <NUM> of the reverse osmosis filter <NUM>.

The second flushing line LF2 may be connected to the residential water line LL. The second flushing line LF2 may include a second flushing valve VF2. When the second flushing valve VF2 is opened, as illustrated in <FIG>, the water flowing into the non-filtration side <NUM> of the reverse osmosis filter <NUM> may not pass through the reverse osmosis membrane MB and may flow to the second flushing line LF2 through the residential water line LL. Accordingly, the non-filtration side <NUM> of the reverse osmosis filter <NUM> may be flushed by the water flowing into the non-filtration side <NUM>.

The filter unit <NUM> may further include a pre-treatment filter <NUM> and a post-treatment filter <NUM> as illustrated in <FIG>.

The pre-filter <NUM> may be connected to the water inlet line LI. For example, the pre-treatment filter <NUM> may be connected to a portion of the water inlet line LI before the water inlet pump PI and the water inlet valve VI. However, the portion of the water inlet line LI to which the pretreatment filter <NUM> is connected is not particularly limited, and may be connected to any portion of the water inlet line LI before the reverse osmosis filter <NUM>. When the water inlet valve VI is opened, the water of the water supply source may be filtered by the pre-treatment filter <NUM> and may flow to the non-filtration side <NUM> of the reverse osmosis filter <NUM> as illustrated in <FIG>.

The post-treatment filter <NUM> may be connected to the water outlet line LO. For example, the post-treatment filter <NUM> may be connected to a portion of the water outlet line LO between a portion to which the first flushing line LF1 is connected and the water outlet valve VO. Accordingly, as illustrated in <FIG>, the water filtered by the reverse osmosis filter <NUM> may be filtered by the post-treatment filter <NUM> and may flow to the water outlet unit <NUM> through the water outlet line LO.

The water filter included in the filter unit <NUM> in addition to the reverse osmosis filter <NUM> is not limited to the above-described pre-treatment filter <NUM> and post-treatment filter <NUM>, and any water filter able to filter water may be used. Also, the number of water filters included in the filter unit <NUM> in addition to the reverse osmosis filter <NUM> is not particularly limited, and any number of the filters may be provided. Alternatively, only the reverse osmosis filter <NUM> may be included in the filter unit <NUM>.

The water outlet unit <NUM> may include a water outlet member <NUM>. The water outlet member <NUM> may be connected to the filter unit <NUM>. For example, the water outlet member <NUM> may be connected to the water outlet line LO and may be connected to the filter unit <NUM> as illustrated in <FIG>. Accordingly, when the water outlet valve VO of the water outlet line LO is opened, the water filtered by the filter <NUM> may flow to the water outlet member <NUM> through the water outlet line LO as illustrated in <FIG>. Also, the water flowing to the water outlet member <NUM> may be discharged to the outside through the water outlet member <NUM> and may be supplied to a user.

The control unit <NUM> may allow the water filtered by the filter unit <NUM> to be discharged to the outside through the water outlet member <NUM>.

The control unit <NUM> may be connected to the water inlet valve VI, the water inlet pump PI, and the water outlet valve VO. Also, the control unit <NUM> may be connected to the first flushing valve VF1 and the second flushing valve VF2.

When the control unit <NUM> opens the water inlet valve VI and drives the water inlet pump PI, as illustrated in <FIG>, the water of the water supply source may flow into the pre-treatment filter <NUM> of the filter unit <NUM> through the water inlet line LI and may be filtered. Water filtered by the pre-treatment filter <NUM> may flow into the non-filtration side <NUM> of the reverse osmosis filter <NUM> of the filter unit <NUM> through the water inlet line LI. Some of the water flowing into the non-filtration side <NUM> of the reverse osmosis filter <NUM> may be filtered while passing through the reverse osmosis membrane MB and may flow to the filtration side <NUM> of the reverse osmosis filter <NUM>. In this state, when the control unit <NUM> opens the water outlet valve VO, the water filtered while passing through the reverse osmosis membrane MB and flowing to the filtration side <NUM> of the reverse osmosis filter <NUM> may flow to the water outlet member <NUM> of the water outlet unit <NUM> through the water outlet line LO. The water flowing to the water outlet member <NUM> of the water outlet unit <NUM> may be discharged to the outside through the water outlet member <NUM> and may be supplied to a user.

Meanwhile, as illustrated in <FIG>, the control unit <NUM> may allow the filtration side <NUM> of the reverse osmosis filter <NUM> of the filter unit <NUM> to be flushed before the water filtered by the filter unit <NUM> is discharged through the water outlet member <NUM> of the water outlet unit <NUM>.

In the case in which filtration of water is not performed for a predetermined time or more in the reverse osmosis filter <NUM> of the filter unit <NUM>, due to a difference in total dissolved solid (TDS) concentrations between the non-filtration side <NUM> and the filtration side <NUM> of the reverse osmosis filter <NUM>, the water on the non-filtration side <NUM> may pass through the reverse osmosis membrane MB and may flow to the filtration side <NUM>. Accordingly, the concentrations of TDS of the non-filtration side <NUM> and the filtration side <NUM> of the reverse osmosis filter <NUM> may become the same, which may be called a creepage phenomenon. Due to this creepage phenomenon, water having a relatively high concentration of TDS may be present on the filtration side <NUM> of the reverse osmosis filter <NUM>.

In the present disclosure, as described above, before the water filtered by the filter unit <NUM> is discharged through the water outlet member <NUM>, as illustrated in <FIG>, the filtration side <NUM> of the reverse osmosis filter <NUM> of the filter unit <NUM> may be flushed. Accordingly, water having a relatively high concentration of TDS may be prevented on the filtration side <NUM> of the reverse osmosis filter <NUM>. Accordingly, when water having a relatively high concentration of TDS is not present on the filtration side <NUM> of the reverse osmosis filter <NUM>, water having a relatively low concentration of TDS may be provided to a user.

The control unit <NUM> may allow the filtration side <NUM> of the reverse osmosis filter <NUM> to be flushed for a predetermined time.

For example, the control unit <NUM> may open the water inlet valve VI and may drive the water inlet pump PI, and in this state, the control unit <NUM> may open the first flushing valve VF1 for a predetermined time, and thereafter, the control unit <NUM> may close the first flushing valve VF1. Also, the control unit <NUM> may open the water outlet valve VO.

Accordingly, the filtration side <NUM> of the reverse osmosis filter <NUM> of the filter unit <NUM> may be filtered while passing through the reverse osmosis membrane MB and may be flushed for a predetermined time by the water flowing through the filtration side <NUM>. Also, water having a relatively low concentration of TDS may be present on the filtration side <NUM> of the reverse osmosis filter <NUM>.

In this case, the control unit <NUM> may open the first flushing valve VF1 for at least <NUM> seconds or more.

<FIG> is a graph of TDS concentration of water flowing in a portion of the water outlet line adjacent to the reverse osmosis filter over time when water is not filtered for <NUM> minutes and <NUM> minutes in the reverse osmosis filter of a conventional water purifier, and is filtered in the reverse osmosis filter thereafter. As illustrated in <FIG>, in the conventional water purifier, when the filtration is resumed by the reverse osmosis filter <NUM>, the portion of the water outlet line LO adjacent to the reverse osmosis filter <NUM> may not be affected by the creepage phenomenon, such that water having a relatively low concentration of TDS may flow for about <NUM> seconds. Thereafter, after <NUM> seconds, the water having a relatively high concentration of TDS due to the creepage phenomenon, which has been discharged from the filtration side <NUM> of the reverse osmosis filter <NUM>, may flow through the portion of the water outlet line LO adjacent to the reverse osmosis filter <NUM>. Accordingly, flushing of the filtration side <NUM> of the reverse osmosis filter <NUM> may be performed only when the first flushing valve VF1 is opened for at least <NUM> seconds.

As the filtration side <NUM> of the reverse osmosis filter <NUM> is flushed, as illustrated in <FIG>, the concentration of TDS of the water flowing through the water outlet line LO adjacent to the reverse osmosis filter <NUM> may gradually decrease. As illustrated in <FIG>, when the first flushing valve VF1 is opened for about <NUM> seconds, the concentration of TDS of the water flowing through the water outlet line LO adjacent to the reverse osmosis filter <NUM> may be lowered to about a reference concentration of TDS. Also, when the first flushing valve VF1 is opened for about <NUM> seconds, the concentration of TDS may be lowered to a level of the concentration of TDS of water which the creepage phenomenon may not affect. Meanwhile, when the first flushing valve VF1 is opened for more than <NUM> minute, a relatively large amount of water may be used for flushing the filtration side <NUM> of the reverse osmosis filter <NUM>. Also, to receive the water filtered by the filter unit <NUM>, a user may have to wait a relatively long time. Accordingly, it may be preferable to allow the filtration side <NUM> of the reverse osmosis filter <NUM> to be flushed by opening the first flushing valve VF1 for <NUM> seconds or more and <NUM> minute or less.

Meanwhile, the minimum opening time of the first flushing valve VF1 for flushing the filtration side <NUM> of the reverse osmosis filter <NUM> may be less than <NUM> seconds or more than <NUM> seconds depending on the installation environment of the water purifier <NUM>.

Here, the TDS removal rate may be represented as below, where the concentration of TDS of the raw water may indicate the concentration of TDS of the water of the water supply source, and the concentration of TDS of the purified water may indicate the concentration of TDS of the water passing through the filter unit <NUM> and discharged through the water outlet member <NUM> of the water outlet unit <NUM>.

A relatively high TDS removal rate may indicate that the concentration of TDS of the purified water may be relatively low, and a relatively low TDS removal rate may indicate that the concentration of TDS of the purified water may be relatively high.

As illustrated in <FIG>, in the case of the conventional water purifier to which the flushing of the filtration side <NUM> of the reverse osmosis filter <NUM> is not applied, and the case of the water purifier <NUM> to which the flushing of the filtration side <NUM> of the reverse osmosis filter <NUM> is applied, water having relatively low TDS which was not affected by the creepage phenomenon was put in the first cup through the water outlet member <NUM> of the water outlet unit <NUM>. Also, water having a relatively high TDS affected by the creepage phenomenon was put in the second glass through the water outlet member <NUM> of the water outlet unit <NUM>, and the TDS removal rate was the lowest. Also, the concentration of TDS of the water discharged to the outside through the water outlet member <NUM> of the water outlet unit <NUM> gradually decreased toward the fifth cup, and the TDS removal rate of the water contained in the glass increased.

In this case, in the case of the conventional water purifier to which flushing of the filtration side <NUM> of the reverse osmosis filter <NUM> is not applied, as illustrated in <FIG>, a difference between the TDS removal rate in the second cup and the TDS removal rate in the fifth cup was relatively large. However, in the case of the water purifier <NUM> according to the present disclosure to which the flushing of the filtration side <NUM> of the reverse osmosis filter <NUM> is applied, the difference between the TDS removal rate in the second cup and the TDS removal rate in the fifth cup was relatively small. Accordingly, it is indicated that the water purifier <NUM> according to the present disclosure to which the flushing of the filtration side <NUM> of the reverse osmosis filter <NUM> is applied may provide water having a relatively low concentration of TDS to a user as compared to the conventional water purifier to which the flushing of the filtration side <NUM> of the reverse osmosis filter <NUM> is not applied.

Meanwhile, the control unit <NUM> may allow the water filtered by the filter unit <NUM> to be discharged through the water outlet member <NUM> of the water outlet unit <NUM> and may allow the non-filtration side <NUM> of the reverse osmosis filter <NUM> to be flushed. Accordingly, the concentration of TDS of water present on the non-filtration side <NUM> of the reverse osmosis filter <NUM> may be relatively low. Accordingly, the creepage phenomenon may not occur, or even when the creepage phenomenon occurs, water having a relatively low concentration of TDS may be present on the filtration side <NUM> of the reverse osmosis filter <NUM>. Accordingly, water having a relatively low concentration of TDS may be provided to a user.

The control unit <NUM> may allow the non-filtration side <NUM> of the reverse osmosis filter <NUM> to be flushed in response to the time for which the water filtered by the filter unit <NUM> is discharged through the water outlet member <NUM> of the water outlet unit <NUM> or the amount of the water.

For example, the control unit <NUM> may close the water outlet valve VO and then may open the second flushing valve VF2. Also, the control unit <NUM> may open the second flushing valve VF2 in response to the time for which the water outlet valve VO is opened or the amount of water discharged through the water outlet member <NUM> of the water outlet unit <NUM>.

<FIG> is a graph of changes in concentration of TDS on the non-filtration side of the reverse osmosis filter over time when water filtered by the reverse osmosis filter is discharged through the water outlet member of the water outlet unit in the water purifier according to the present disclosure, and changes in concentration of TDS on the non-filtration side of the reverse osmosis filter over time when the non-filtration side of the reverse osmosis filter after is flushed after water is discharged through the water outlet member.

As illustrated in <FIG>, by flushing the non-filtration side <NUM> of the reverse osmosis filter <NUM> for the time for which water is discharged through the water outlet member <NUM>, the concentration of TDS of the water present on the non-filtration side <NUM> of the reverse osmosis filter <NUM> may be lowered to the concentration of TDS of the initial discharge of the water outflow member <NUM>. Accordingly, by flushing the non-filtration side <NUM> of the reverse osmosis filter <NUM> by opening the second flushing valve VF2 in response to the time for which the water outlet valve VO is opened or the amount of water discharged through the water outlet member <NUM> of the water outlet unit <NUM>, the concentration of TDS of the water present on the non-filtration side <NUM> of the reverse osmosis filter <NUM> may become relatively low.

For example, the non-filtration side <NUM> of the reverse osmosis filter <NUM> may be flushed by opening the second flushing valve VF2 for one time or more to two times or less the time for which the water outlet valve VO is opened. Also, the second flushing valve VF2 may be opened to flush the non-filtration side <NUM> of the reverse osmosis filter <NUM> by one time or more to two times or less the amount of water discharged through the water outlet member <NUM> of the water outlet unit <NUM>. In this case, when the non-filtration side <NUM> of the reverse osmosis filter <NUM> is flushed by opening the second flushing valve VF2 more than twice the time for which the water outlet valve VO is opened, a relatively large amount of water may be used for flushing the filtration side <NUM> of the reverse osmosis filter <NUM>. Also, even when the second flushing valve VF2 is opened to flush the non-filtration side <NUM> of the reverse osmosis filter <NUM> by more than twice the amount of water discharged through the water outlet member <NUM> of the water outlet unit <NUM>, a relatively large amount of water may be used for flushing the non-filtration side <NUM> of the reverse osmosis filter <NUM>. Accordingly, it may be preferable to flush the non-filtration side <NUM> of the reverse osmosis filter <NUM> by opening the second flushing valve VF2 by one time or more to two times or less the time for which the water outlet valve VO is opened, or to open second flushing valve VF2 to flush the non-filtration side <NUM> of the reverse osmosis filter <NUM> by one time or more to two times or less the amount of water discharged through the water outlet member <NUM> of the water outlet unit <NUM>.

Accordingly, after opening the second flushing valve VF2 to flush the non-filtration side <NUM> of the reverse osmosis filter <NUM>, the control unit <NUM> may close the second flushing valve VF2. Thereafter, the control unit <NUM> may close the water inlet valve VI and may stop the driving of the water inlet pump PI.

Hereinafter, another embodiment of the water purifier according to the present disclosure will be described with reference to FIG.

Here, another embodiment of the water purifier according to the present disclosure may be different from the water purifier according to the present disclosure described with reference to <FIG> in that the residential water line LL may include the shut-off valve VS connected to the control unit <NUM> and the control unit <NUM> may close the shut-off valve VS when the first flushing valve VF1 is opened.

Accordingly, in the description below, the different configurations will be mainly described, and the other configurations may be replaced with the descriptions described with reference to <FIG> above.

In another embodiment of the water purifier <NUM> according to the present disclosure, a shut-off valve VS connected to the control unit <NUM> may be provided in the residential water line LL. Also, when the first flushing valve VF1 is opened to flush the filtration side <NUM> of the reverse osmosis filter <NUM>, the control unit <NUM> may close the shut-off valve VS. Accordingly, more water from the non-filtration side <NUM> of the reverse osmosis filter <NUM> may flow through the reverse osmosis membrane MB and may flow to the filtration side <NUM> of the reverse osmosis filter <NUM> and may flush the filtration side <NUM>. Accordingly, the flushing of the filtration side <NUM> of the reverse osmosis filter <NUM> may be more properly performed.

Claim 1:
A method of controlling a water purifier (<NUM>) by a control unit (<NUM>) of the water purifier (<NUM>), the method comprising:
(a) flushing a filtration side (<NUM>) of a reverse osmosis filter (<NUM>) of a filter unit (<NUM>) of the water purifier (<NUM>) before water is discharged in step (b), wherein the reverse osmosis filter (<NUM>) includes a reverse osmosis membrane (MB) for filtering water such that the reverse osmosis filter (<NUM>) is partitioned into a non-filtration side (<NUM>) and the filtration side (<NUM>);
(b) discharging water filtered by the filter unit (<NUM>) to the outside through a water outlet member (<NUM>) of a water outlet unit (<NUM>) of the water purifier (<NUM>) connected to the filter unit (<NUM>); and
(c) flushing the non-filtration side (<NUM>) after water is discharged in step (b).