Concentrated water utilization method and concentrated water utilization device of water purification equipment

Abstract

The invention relates to the technical field of water treatment, in particular to a concentrated water utilization method and a concentrated water utilization device of water purification equipment. According to the concentrated water utilization method of the water purification equipment, the concentrated water discharged by the water purification equipment can be stored in the storage barrel, the concentrated water stored in the storage barrel can supplement water for the water utilization equipment, and the concentrated water utilization method of the water purification equipment comprises the following steps: judging whether the storage barrel is cleaned or not; when the storage barrel is cleaned, the storage barrel stops storing the concentrated water discharged by the water purifying equipment and stops supplementing water to the water consuming equipment through the concentrated water stored in the storage barrel, and the concentrated water stored in the storage barrel is discharged and the storage barrel is sterilized and disinfected. According to the concentrated water utilization device provided by the invention, the concentrated water discharged by the water purification equipment is utilized by adopting the concentrated water utilization method of the water purification equipment, so that the reutilization of the concentrated water is realized, the water resource is saved, and the safety of the utilized concentrated water is also ensured.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and in particular to a method and apparatus for utilizing concentrated water from a water purification device. Background Technology

[0002] Currently, water purification equipment produces a significant amount of concentrated wastewater while filtering and generating pure water. Directly discharging this concentrated wastewater leads to severe water waste. In related technologies, the concentrated wastewater from the purification equipment is typically supplied to toilet bowls or kitchen sinks. However, in the process of reusing this concentrated wastewater, it is usually first collected and stored in a tank for later use in other water-using devices. However, when the concentrated wastewater in the tank is not used for a long time or at high temperatures, bacteria can easily grow inside, even causing foul odors, greatly reducing the safety of the reused concentrated wastewater.

[0003] Therefore, there is an urgent need for a method and device for utilizing concentrated water from a water purification system to solve the above problems. Summary of the Invention

[0004] The purpose of this invention is to provide a method and apparatus for utilizing concentrated water from a water purification device, so as to utilize the concentrated water discharged from the water purification device, realize the reuse of concentrated water, save water resources, and ensure the safety of the concentrated water used.

[0005] To achieve this objective, the present invention adopts the following technical solution:

[0006] A method for utilizing concentrated water from a water purification device, wherein the concentrated water discharged from the water purification device can be stored in a storage tank, and the concentrated water stored in the storage tank can be used to replenish water for water-using equipment, the method for utilizing concentrated water from the water purification device includes the following steps:

[0007] Determine whether to perform a cleaning operation on the storage tank;

[0008] When the storage tank is cleaned, the storage tank stops storing the concentrated water discharged from the water purification equipment and stops using the concentrated water stored in the storage tank to replenish the water-using equipment. The concentrated water stored in the storage tank is discharged and the storage tank is sterilized and disinfected.

[0009] As an optional solution, determining whether to clean the storage tank includes the following steps:

[0010] The content of bacteria and microorganisms in the storage tank is monitored in real time;

[0011] When the bacterial and microbial content in the storage container reaches a preset value, the storage container is cleaned.

[0012] As an optional solution, determining whether to clean the storage tank includes the following steps:

[0013] When a preset time has elapsed since the last cleaning operation of the storage tank, the storage tank is then cleaned.

[0014] As an optional solution, when no cleaning operation is performed on the storage tank, and when the liquid level in the storage tank is not lower than the first preset water level, the concentrated water stored in the storage tank is used to replenish the water-using equipment.

[0015] As an optional solution, when the liquid level in the storage tank is lower than the first preset water level or when the storage tank is cleaned, the water-using equipment can be replenished with municipal water.

[0016] As an optional solution, when no cleaning operation is performed on the storage tank and when the liquid level in the storage tank is not higher than the second preset water level, the concentrated water discharged by the water purification equipment is stored in the storage tank, wherein the second preset water level is higher than the first preset water level.

[0017] A concentrated water utilization device utilizes the concentrated water discharged from the water purification equipment as described above, the concentrated water utilization device comprising:

[0018] A storage tank, wherein the storage tank is connected to the concentrated water drain end of the water purification equipment, and the storage tank is also connected to a water-using device; and

[0019] A sterilization component is disposed inside the storage tank and is configured to sterilize and disinfect the storage tank.

[0020] As an optional solution, the concentrate utilization device further includes:

[0021] A concentrate replenishment pipeline, wherein the inlet end of the concentrate replenishment pipeline is connected to the storage tank, and the outlet end of the concentrate replenishment pipeline is connected to the water-using equipment; and

[0022] A water pump is installed on the concentrate replenishment pipeline.

[0023] As an optional solution, multiple water-using devices are provided, and the concentrated water supply pipeline includes:

[0024] A main water supply pipe, the inlet of which is connected to the storage tank, and a water pump mounted on the main water supply pipe; and

[0025] Multiple water supply branch pipes are provided, each of which is connected to the outlet of the main water supply pipe, and the outlet of each water supply branch pipe is connected to a corresponding water-using device.

[0026] As an optional solution, the concentrate utilization device further includes:

[0027] A concentrated water drainage pipe, wherein the inlet end of the concentrated water drainage pipe is connected to the concentrated water drainage end of the water purification equipment, and the outlet end of the concentrated water drainage pipe is connected to the storage tank; and

[0028] The first solenoid valve is installed on the concentrated water drainage pipeline.

[0029] The beneficial effects of this invention are:

[0030] This invention provides a method for utilizing concentrated water from a water purification device. The concentrated water discharged from the water purification device can be stored in a storage tank, and the concentrated water stored in the storage tank can be used to replenish water for water-using devices, thereby improving the utilization rate of the concentrated water discharged from the water purification device, realizing the reuse of concentrated water, and saving water resources. Furthermore, the method for utilizing concentrated water from a water purification device provided by this invention determines whether a cleaning operation is required for the storage tank. When a cleaning operation is required, the storage tank stops storing the concentrated water discharged from the water purification device and stops using the concentrated water stored in the storage tank to replenish water for water-using devices. The concentrated water stored in the storage tank is discharged, and the storage tank is sterilized and disinfected, thereby preventing bacterial growth in the storage tank, preventing the storage tank from becoming smelly, and effectively ensuring the safety of the utilized concentrated water.

[0031] The present invention also provides a concentrated water utilization device. The concentrated water utilization device provided by the present invention utilizes the concentrated water discharged from the water purification equipment by adopting the concentrated water utilization method of the above-mentioned water purification equipment. This not only improves the utilization rate of the concentrated water discharged from the water purification equipment and realizes the reuse of concentrated water, saving water resources, but also ensures the safety of the concentrated water used. Attached Figure Description

[0032] Figure 1 This is a main flowchart of the concentrated water utilization method of the water purification equipment provided in the embodiments of the present invention;

[0033] Figure 2 This is a schematic diagram of the concentrated water utilization device provided in an embodiment of the present invention;

[0034] Figure 3 This is a detailed flowchart of the concentrated water utilization method of the water purification equipment provided in the embodiments of the present invention.

[0035] In the picture:

[0036] 10. Concentrated water utilization device; 20. Water purification equipment; 301. Water heater; 3011. First valve; 302. Kitchen water equipment; 3021. Second valve; 303. Toilet flushing tank;

[0037] 1. Storage tank; 11. Drain pipe; 12. Switch valve; 2. Concentrate water supply pipeline; 21. Main supply water pipe; 22. Branch supply water pipe; 3. Water pump; 4. Concentrate water drainage pipeline; 5. First solenoid valve; 6. Ball valve; 7. Municipal water supply pipeline; 71. Second solenoid valve. Detailed Implementation

[0038] To make the technical problems solved by the present invention, the technical solutions adopted, and the technical effects achieved clearer, the technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0039] In the description of this invention, unless otherwise explicitly specified and limited, the terms "connected," "linked," and "fixed" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0040] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0041] In the description of this embodiment, the terms "upper," "lower," "left," and "right," etc., refer to the orientation or positional relationship shown in the accompanying drawings. They are used only for ease of description and simplification of operation, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the present invention. In addition, the terms "first" and "second" are used only for distinction in description and have no special meaning.

[0042] Currently, water purification equipment produces a significant amount of concentrated wastewater while filtering and generating pure water. Directly discharging this concentrated wastewater leads to severe water waste. In existing technologies, the concentrated wastewater from the purification equipment is typically supplied to toilet bowls or kitchen sinks. However, in the process of reusing this concentrated wastewater, it is usually first collected and stored in a container for later use in other water-using devices. However, when the concentrated wastewater in the container is not used for a long time or at high temperatures, bacteria can easily grow inside, even causing foul odors, significantly reducing the safety of the reused concentrated wastewater.

[0043] To solve the above problems, such as Figure 1 As shown, this embodiment provides a method for utilizing concentrated water from a water purification device. Specifically, refer to... Figure 1 and Figure 2 As shown, the concentrated water discharged from the water purification equipment 20 can be stored in the storage tank 1, and the concentrated water stored in the storage tank 1 can replenish water for water-using equipment. The method for utilizing the concentrated water from the water purification equipment includes the following steps:

[0044] Determine whether to perform a cleaning operation on storage container 1;

[0045] When cleaning the storage tank 1, the storage tank 1 stops storing the concentrated water discharged from the water purification equipment 20 and stops using the concentrated water stored in the storage tank 1 to replenish the water-using equipment. The concentrated water stored in the storage tank 1 is discharged and the storage tank 1 is sterilized and disinfected.

[0046] The concentrated water utilization method of the water purification equipment provided in this embodiment can store the concentrated water discharged from the water purification equipment 20 into the storage tank 1. The concentrated water stored in the storage tank 1 can be used to replenish water for water-using equipment, improving the utilization rate of the concentrated water discharged from the water purification equipment 20, realizing the reuse of concentrated water, and saving water resources. In addition, the concentrated water utilization method of the water purification equipment provided in this embodiment determines whether to perform a cleaning operation on the storage tank 1. When the storage tank 1 is cleaned, the storage tank 1 stops storing the concentrated water discharged from the water purification equipment 20 and stops replenishing water for water-using equipment with the concentrated water stored in the storage tank 1. The concentrated water stored in the storage tank 1 is discharged and the storage tank 1 is sterilized and disinfected, thereby avoiding the growth of bacteria in the storage tank 1 and preventing the storage tank 1 from smelling bad, effectively ensuring the safety of the concentrated water used.

[0047] Optionally, in this embodiment, as Figure 3 As shown, determining whether to perform a cleaning operation on storage tank 1 includes the following steps:

[0048] Real-time monitoring of bacterial and microbial content within storage container 1;

[0049] When the bacterial and microbial content in storage tank 1 reaches the preset value, storage tank 1 is cleaned.

[0050] The above setup effectively prevents the bacterial and microbial content in storage tank 1 from exceeding the standard, and enables timely cleaning and disinfection of storage tank 1.

[0051] Optionally, in other embodiments, determining whether to perform a cleaning operation on storage tank 1 includes the following steps: when a preset time has elapsed since the last cleaning operation on storage tank 1, then a cleaning operation is performed on storage tank 1. This setting method, by performing a cleaning operation on storage tank 1 at preset time intervals, achieves periodic cleaning of storage tank 1, facilitating operation control.

[0052] In this embodiment, as Figure 3 As shown, when no cleaning operation is performed on storage tank 1 (i.e., when the bacterial and microbial content in storage tank 1 is not detected to have reached the preset value), and when the liquid level in storage tank 1 is not lower than the first preset water level, the concentrated water stored in storage tank 1 is used to replenish the water-using equipment. This setting ensures that storage tank 1 has sufficient concentrated water to replenish the water-using equipment, thus ensuring the reliability of water supply from storage tank 1 to the water-using equipment.

[0053] Optionally, in this embodiment, when the liquid level in the storage tank 1 is lower than the first preset water level or when the storage tank 1 is cleaned (i.e. when the content of bacteria and microorganisms in the storage tank 1 is detected to reach the preset value), water is replenished to the water-using equipment through municipal water to ensure a reliable water supply to the water-using equipment.

[0054] Optionally, in this embodiment, as Figure 3 As shown, when no cleaning operation is performed on storage tank 1 (i.e., when the bacterial and microbial content in storage tank 1 does not reach the preset value), and when the liquid level in storage tank 1 is not higher than the second preset water level, the concentrated water discharged by the water purification device 20 is stored in storage tank 1. The second preset water level is higher than the first preset water level. This configuration avoids the waste of concentrated water discharged by the water purification device 20. It should be noted that when the liquid level in storage tank 1 is higher than the second preset water level or when a cleaning operation is performed on storage tank 1, the concentrated water discharged by the water purification device 20 can be directly discharged into the sewer to avoid overflow of concentrated water from storage tank 1 and to avoid interference with the cleaning operation of storage tank 1.

[0055] like Figure 2As shown, this embodiment also provides a concentrated water utilization device 10. The concentrated water utilization device 10 of this embodiment utilizes the concentrated water utilization method of the aforementioned water purification equipment to utilize the concentrated water discharged from the water purification equipment 20. The concentrated water utilization device 10 includes a storage tank 1 and a sterilization component (not shown in the figure). The storage tank 1 can be connected to the concentrated water drain end of the water purification equipment 20 and can also be connected to a water-using device. The sterilization component is disposed inside the storage tank 1 and is used to sterilize and disinfect the storage tank 1. The concentrated water utilization device 10 of this embodiment utilizes the concentrated water discharged from the water purification equipment 20 by adopting the concentrated water utilization method of the aforementioned water purification equipment. This not only improves the utilization rate of the concentrated water discharged from the water purification equipment 20 and realizes the reuse of concentrated water, saving water resources, but also ensures the safety of the utilized concentrated water.

[0056] Optionally, in this embodiment, the sterilization component can be a UV germicidal lamp or other forms of germicidal lamp, and the specific form of the sterilization component in this embodiment is not limited.

[0057] Optionally, in this embodiment, a drain pipe 11 is provided on the storage tank 1, and a switch valve 12 is provided on the drain pipe 11. When cleaning the storage tank 1, the switch valve 12 is opened so that the concentrated water stored in the storage tank 1 is discharged through the drain pipe 11. When the cleaning operation of the storage tank 1 is completed and the concentrated water is stored through the storage tank 1, the switch valve 12 is closed to prevent the concentrated water in the storage tank 1 from being discharged.

[0058] In this embodiment, the concentrated water utilization device 10 further includes a liquid level detection component (not shown in the figure). The liquid level detection component is disposed inside the storage tank 1 and is used to detect the liquid level inside the storage tank 1. The liquid level detection component determines whether the liquid level inside the storage tank 1 is lower than a first preset water level and whether the liquid level inside the storage tank 1 is higher than a second preset water level. Specifically, the liquid level detection component can be a liquid level gauge.

[0059] In this embodiment, the concentrated water utilization device 10 further includes a bacterial detection component (not shown in the figure). The bacterial detection component is disposed inside the storage tank 1 and is used to detect the content of bacterial microorganisms in the storage tank 1, thereby determining whether the content of bacterial microorganisms has reached a preset value based on the detection value of the bacterial detection component. Specifically, the bacterial detection component can be a bacterial detection sensor.

[0060] In this embodiment, as Figure 2As shown, the concentrated water utilization device 10 also includes a concentrated water supply pipeline 2 and a water pump 3. The inlet end of the concentrated water supply pipeline 2 is connected to the storage tank 1, and the outlet end is connected to the water-using equipment. The water pump 3 is installed on the concentrated water supply pipeline 2. With this configuration, when water needs to be supplied to the water-using equipment via the storage tank 1, the water pump 3 can be activated to pump the concentrated water from the storage tank 1 into the water-using equipment through the concentrated water supply pipeline 2. By installing the water pump 3 on the concentrated water supply pipeline 2, the water pressure supplied by the storage tank 1 to the water-using equipment is ensured, guaranteeing the stability and reliability of the water supply from the storage tank 1 to the water-using equipment.

[0061] In this embodiment, the concentrated water utilization device 10 further includes a concentrated water drain pipe 4 and a first solenoid valve 5. The inlet end of the concentrated water drain pipe 4 is connected to the concentrated water drain end of the water purification device 20, and the outlet end of the concentrated water drain pipe 4 is connected to the storage tank 1. The first solenoid valve 5 is installed on the concentrated water drain pipe 4. When the concentrated water discharged from the water purification device 20 is stored in the storage tank 1, the first solenoid valve 5 is opened so that the concentrated water discharged from the water purification device 20 can be discharged into the storage tank 1 through the concentrated water drain pipe 4.

[0062] Specifically, the concentrated water utilization device 10 is equipped with a control system. The level detection component, bacteria detection component, sterilization component, switching valve 12, water pump 3, and first solenoid valve 5 are all communicatively connected to the control system. It should be noted that the level detection component and bacteria detection component are always operational, the first solenoid valve 5 is normally open, and the switching valve 12, sterilization component, and water pump 3 are normally closed. When the bacteria detection component detects that the bacterial microbial content in the storage tank 1 reaches a preset value, the control system controls the first solenoid valve 5 to close, the switching valve 12 to open, and the sterilization component to open, thereby cleaning the storage tank 1. Furthermore, when the level detection component detects that the liquid level in the storage tank 1 is higher than a second preset water level, the control system controls the first solenoid valve 5 to close. When the level detection component detects that the liquid level in the storage tank 1 is not lower than the first preset water level, and the water-using equipment needs water, the control system controls the water pump 3 to open.

[0063] Optionally, in this embodiment, multiple water-using devices are provided. The concentrated water supply pipeline 2 includes a main supply pipe 21 and multiple supply branch pipes 22. The inlet end of the main supply pipe 21 is connected to the storage tank 1, and the water pump 3 is installed on the main supply pipe 21. The multiple supply branch pipes 22 are all connected to the outlet end of the main supply pipe 21, and the outlet end of each supply branch pipe 22 is connected to a corresponding water-using device. By setting multiple parallel supply branch pipes 22, the concentrated water stored in the storage tank 1 can supply water to multiple water-using devices, meeting the user's needs.

[0064] Specifically, in this embodiment, as Figure 2 As shown, the concentrated water utilization device 10 also includes multiple ball valves 6, which are normally open, and each water supply branch pipe 22 is equipped with a ball valve 6. All ball valves 6 are communicatively connected to the control system. When maintenance is required on the water-using equipment or when the equipment does not require water replenishment, the ball valve 6 on the corresponding water supply branch pipe 22 can be closed to ensure the normal water supply operation of the concentrated water utilization device 10 to other water-using equipment.

[0065] An example is provided, such as Figure 2 As shown, the multiple water-using devices are a water heater 301, a kitchen water-using device 302, and a toilet flushing basin 303. The water heater 301 is equipped with a first valve 3011 at its outlet. When the first valve 3011 is opened, it is determined that the water heater 301 needs to be replenished with water. The kitchen water-using device 302 is equipped with a second valve 3021 at its outlet. When the second valve 3021 is opened, it is determined that the kitchen water-using device 302 needs to be replenished with water. The toilet flushing basin 303 is equipped with a level gauge. When the level gauge detects that the water level in the toilet flushing basin 303 is lower than the standard water level, it is determined that the toilet flushing basin 303 needs to be replenished with water.

[0066] Optionally, in this embodiment, as Figure 2 As shown, the concentrated water utilization device 10 also includes multiple municipal water supply pipes 7, which are connected to corresponding water-using equipment. Each municipal water supply pipe 7 is equipped with a second solenoid valve 71, which is connected to the control system. Each second solenoid valve 71 is normally closed. When the bacterial detection component detects that the bacterial microbial content in the storage tank 1 reaches a preset value or the liquid level detection component detects that the liquid level in the storage tank 1 is lower than the first preset water level, and the water-using equipment needs to use water at this time, the control system controls the second solenoid valve 71 corresponding to the water-using equipment that needs to be replenished to open.

[0067] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. Those skilled in the art can make other variations or modifications based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for utilizing concentrated water from a water purification device, characterized in that, The concentrated water discharged by the water purification equipment (20) can be stored in the storage tank (1), and the concentrated water stored in the storage tank (1) can replenish water for water-using equipment. The method for utilizing the concentrated water of the water purification equipment includes the following steps: Determine whether to perform a cleaning operation on the storage tank (1); When the storage tank (1) is cleaned, the storage tank (1) stops storing the concentrated water discharged by the water purification equipment (20) and stops replenishing the water-using equipment with the concentrated water stored in the storage tank (1). The concentrated water stored in the storage tank (1) is discharged and the storage tank (1) is sterilized and disinfected.

2. The method for utilizing concentrated water from the water purification equipment according to claim 1, characterized in that, The determination of whether to perform a cleaning operation on the storage tank (1) includes the following steps: The content of bacteria and microorganisms in the storage tank (1) is monitored in real time; When the content of bacteria and microorganisms in the storage tank (1) is detected to reach a preset value, the storage tank (1) is cleaned.

3. The method for utilizing concentrated water from the water purification equipment according to claim 1, characterized in that, The determination of whether to perform a cleaning operation on the storage tank (1) includes the following steps: When the time since the last cleaning operation of the storage tank (1) reaches a preset time, the storage tank (1) is cleaned.

4. The method for utilizing concentrated water from a water purification device according to any one of claims 1 to 3, characterized in that, When no cleaning operation is performed on the storage tank (1), and when the liquid level in the storage tank (1) is not lower than the first preset water level, the concentrated water stored in the storage tank (1) is used to replenish the water-using equipment.

5. The method for utilizing concentrated water from the water purification equipment according to claim 4, characterized in that, When the liquid level in the storage tank (1) is lower than the first preset water level or when the storage tank (1) is cleaned, the water-using equipment is replenished with municipal water.

6. The method for utilizing concentrated water from the water purification equipment according to claim 4, characterized in that, When no cleaning operation is performed on the storage tank (1), and when the liquid level in the storage tank (1) is not higher than the second preset water level, the concentrated water discharged by the water purification equipment (20) is stored in the storage tank (1), wherein the second preset water level is higher than the first preset water level.

7. A concentrated water utilization device, characterized in that, The concentrated water discharged from the water purification equipment (20) is utilized using the concentrated water utilization method of the water purification equipment according to any one of claims 1 to 6, wherein the concentrated water utilization device comprises: A storage tank (1) is connected to the concentrated water drain end of the water purification device (20), and the storage tank (1) is also connected to a water-using device; and A sterilization component is disposed inside the storage tank (1) and is configured to sterilize and disinfect the storage tank (1).

8. The concentrated water utilization device according to claim 7, characterized in that, The concentrated water utilization device also includes: A concentrate replenishment pipeline (2), wherein the inlet end of the concentrate replenishment pipeline (2) is connected to the storage tank (1), and the outlet end of the concentrate replenishment pipeline (2) is connected to the water-using equipment; and A water pump (3) is installed on the concentrate replenishment pipeline (2).

9. The concentrated water utilization device according to claim 8, characterized in that, The water-using equipment is provided in multiple locations, and the concentrated water supply pipeline (2) includes: A water supply main pipe (21), the inlet end of which is connected to the storage tank (1), and a water pump (3) mounted on the water supply main pipe (21); and Multiple water supply branch pipes (22) are connected to the outlet end of the main water supply pipe (21), and the outlet end of each water supply branch pipe (22) is connected to a corresponding water-using device.

10. The concentrated water utilization device according to claim 7, characterized in that, The concentrated water utilization device also includes: A concentrated water drainage pipe (4) is provided, with its inlet end connected to the concentrated water drainage end of the water purification equipment (20) and its outlet end connected to the storage tank (1). The first solenoid valve (5) is installed on the concentrated water drainage pipeline (4).

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