TW201323067A - Device for producing desalted water and method for producing the same - Google Patents

Abstract

This invention provides a device for producing desalted water and a method for producing desalted water from raw water by the device for producing desalted water. In a desalted water producing device, preprocessing water which is produced from raw water by being preprocessed by a sand filtration device or a preprocessing device 5 such as a preprocessing membrane module having a precise ultra-filtration membrane and/or an ultra-filtration membrane, is provided to a reverse osmosis device 10 directly without passing through an intermediate tank. Thereby, a backwash can be performed through the preprocessing device 5 without damaging the stable operation of the reverse osmosis device 10.

Description

Fresh water manufacturing device and method for manufacturing fresh water

The present invention relates to a fresh water producing apparatus and a fresh water manufacturing method for treating raw water by a pretreatment apparatus to produce pretreated water, and treating the pretreated water by a reverse osmosis membrane apparatus to produce fresh water.

The fresh water manufacturing apparatus having a reverse osmosis membrane module used for desalination of seawater has the advantages of energy saving and space saving, and therefore, it is expanded in various fields. For example, there may be mentioned a water purification treatment for producing industrial water or tap water from river water, ground water or sewage treatment water, or a sewage treatment reverse osmosis membrane treatment step or a seawater desalination reverse osmosis membrane treatment step. The reverse osmosis membrane separation device used in seawater desalination or the like basically supplies the treated liquid to a predetermined pressure by a high pressure pump and supplies it to the reverse osmosis membrane module, and thereby reverse osmosis by the reverse osmosis membrane module. The dissolved component in the liquid to be treated is separated to obtain a method of permeating water.

As shown in Fig. 5, the fresh water producing apparatus including the reverse osmosis membrane module transports the liquid before the liquid is supplied from the raw water tank 1 by the raw water supply pump 3 and filters the apparatus 5. In the above-described steps, a pretreatment device such as a membrane pretreatment device comprising a sand filter device or a microfiltration membrane or an ultrafiltration membrane is generally used. The pretreated water filtered by the processing device 5 is temporarily stored in the intermediate tank 15, and the treated water is supplied to the reverse osmosis membrane module 9 of the reverse osmosis membrane device 10 by the high pressure pump 7 and processed. However, this method has the disadvantage that microorganisms are generated in the intermediate tank 15 and the reverse osmosis membrane module 9 is easily contaminated, and In the case of the tank 15, there is a case where the suction pressure of the high pressure pump 7 is insufficient. In this case, it is necessary to provide a booster pump 16 on the supply side of the high pressure pump 7, so that the equipment cost is excessive.

In order to solve this problem, for example, in the methods described in Patent Documents 1 and 2, a means for directly supplying pre-treated water to a reverse osmosis membrane device by a pretreatment apparatus and performing processing thereof has been proposed. It is characterized in that it is not necessary to provide an intermediate groove which is conventionally necessary.

On the other hand, when the current treatment device is a sand filter device or a membrane pretreatment device, the object to be removed such as turbidity, organic matter, or inorganic matter contained in the raw water is accumulated, and the filtration resistance of the pretreatment device is increased, and the result cannot be continued. Filter. Therefore, in order to suppress an increase in the filtration impedance of the pretreatment apparatus, it is necessary to periodically perform back pressure cleaning (hereinafter referred to as a backwashing step) from the pretreatment water side to the raw water side in the pretreatment apparatus. In this backwashing step, a series of previous processing steps of a plurality of series or a series of previously defined processing devices is isolated from the running series. In the absence of an intermediate tank, since the pretreatment device is directly connected to the reverse osmosis membrane device, pressure fluctuations to the reverse osmosis membrane device are caused at the beginning of the backwashing step of the pretreatment device and when the process is transferred to the operation step. There is a possibility of damaging the stable operation of the reverse osmosis membrane device.

Patent Document 1 proposes a method of using reverse osmosis concentrated water for backwashing of a pretreatment membrane. However, a specific operation method in the backwashing step is not described, and stable operation of the reverse osmosis membrane device may not be performed. . Further, in Patent Document 2, it is proposed that in the system in which the pretreatment device and the reverse osmosis membrane device are directly connected, the flow rate control of the pretreatment device and the flow rate control of the reverse osmosis membrane device are used, even if the system of the pretreatment device is The column is a means for stably feeding the reverse osmosis membrane device in the backwashing step. However, in the case where the flow control is used in series in the series in which the pretreatment device and the reverse osmosis membrane device are directly connected, it is possible that each flow control will mutually Interference and instability of flow control.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. Hei 10-263539

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2007-181822

An object of the present invention is to provide a fresh water producing apparatus and a method for producing fresh water for producing fresh water from raw water by the fresh water producing apparatus, wherein the fresh water producing apparatus uses raw sand by a sand filtering device or has a fine filtering membrane and/or The pre-treatment device such as the ultra-filtration membrane pretreatment unit performs pretreatment, and the previously treated water obtained is directly supplied to the fresh water production apparatus of the reverse osmosis membrane device without passing through the intermediate tank, wherein the stability of the reverse osmosis membrane device is not impaired. It is operated to perform backwashing of the pretreatment apparatus.

In order to solve the above problems, the fresh water production apparatus and the fresh water production method of the present invention have the following features.

(1) A fresh water producing apparatus comprising: a pretreatment apparatus comprising a plurality of series of pretreated water produced by treating raw water; a reverse osmosis membrane apparatus for treating the pretreated water to produce fresh water; and supplying the raw water to the pretreatment a raw water supply pump of the device; the pretreatment water is supplied to the high pressure pump of the reverse osmosis membrane device; one end is connected to the raw water supply unit and the other end is connected a first raw water supply pipe connected to the raw water supply pump; one end connected to the raw water supply pump and the other end connected to each of the series of second raw water supply pipes; and one end connected to each series of the pretreatment device The other end is connected to the first connecting pipe of the high pressure pump; and the second connecting pipe is connected to the high pressure pump at one end and connected to the reverse osmosis membrane device at the other end; wherein the fresh water manufacturing device further includes: the first connection is provided a pressure gauge for measuring the treated water pressure supplied to the pretreatment water of the high pressure pump; and a bypass pipe that is branched from the second raw water supply pipe and discharged to the outside of the system; and is disposed at the bypass A pressure control valve on the piping that controls the water pressure of the treatment.

(2) The fresh water producing apparatus according to the above (1), wherein the second raw water supply pipe includes: a flow meter that measures a flow rate of raw water supplied to each of the pretreatment apparatuses; and a control supply to the pretreatment A flow control valve for the raw water flow of each series of devices.

(3) A method for producing fresh water from raw water by the fresh water producing apparatus according to (1) or (2) above, comprising: when performing the backwashing step of the processing apparatus, The pressure water pressure control valve described above is used to control the water pressure in the process to be constant.

(4) A method for producing fresh water from raw water by the fresh water producing apparatus according to (2) above, wherein the manufacturing method includes a backwashing step of the processing apparatus, and using the aforementioned The flow meter and the flow rate control valve control the flow rate of the raw water supplied to the pretreatment device in the backwashing step to be constant.

(5) A method for producing fresh water, which is the fresh water as described in the above (4) In the manufacturing method, the pressure is controlled to be constant by using the pressure gauge and the pressure control valve.

According to the present invention, the backwashing of the pretreatment apparatus can be performed while preventing the contamination of the reverse osmosis membrane in a simple manner, and the operation can be stably performed.

[Formation of the Invention]

The invention will be described in more detail below on the basis of the embodiment shown in the drawings. Further, the present invention is not limited to the following embodiments.

The fresh water producing apparatus of the present invention includes, as shown in Fig. 1, a raw water tank 1 for storing raw water, and a pre-processing apparatus 5 comprising a plurality of series of pre-treated water for processing raw water; and processing the pre-treated water to produce fresh water. a reverse osmosis membrane device 10; a raw water supply pump 3 that supplies the raw water to the pretreatment device 5; and a pretreatment water supplied to the high pressure pump 7 of the reverse osmosis membrane device 10; one end is connected to the raw water tank 1 and the other end is connected The first raw water supply pipe 2 of the raw water supply pump 3; one end connected to the raw water supply pump 3 and the other end connected to the second raw water supply pipe 4 of each series of the pretreatment device 5; one end connected to the pretreatment device 5 Each of the other series is connected to the first connecting pipe 6 of the high pressure pump 7; the second connecting pipe 8 is connected to the high pressure pump 7 at one end and connected to the reverse osmosis membrane device 10 at the other end; A pressure gauge 11 that measures the treated water pressure of the pretreatment water supplied to the high pressure pump 7 on the first connecting pipe 6, and a bypass pipe 12 that branches off the second raw water supply pipe 4 and discharges the raw water to the outside of the system ; and set in 12 and controls the processing pressure of the pressure control valve through the pipe 13.

The raw water to which the present invention can be applied can be exemplified by sea water, river water, and ground water. Sewer water treatment of various raw water such as water.

In consideration of the backwashing step, the pretreatment device may be composed of a plurality of series, and in terms of the device, it may be a structure in which the sand filter device or the sand filter device is directly connected in two stages. Further, it may be a pretreatment apparatus having a fine filtration membrane and/or an ultrafiltration membrane.

The pretreatment membrane module 20 used in the pretreatment apparatus 5 is an ultrafiltration membrane that can prevent particles or polymers of 0.1 μm or more from being finely filtered, or can prevent particles or polymers of 2 nm or more and less than 0.1 μm. There is no special limit. A hollow membrane type, a flat membrane type, a spiral type, or a tubular type can be used as the microfiltration membrane and/or the ultrafiltration membrane used in the pretreatment membrane module 20, but the viewpoint of cost reduction is hollow. The membrane type is preferred. In addition, the membrane filtration method can also be a full-size filter module or a cross-filter module, but from the viewpoint of energy consumption, it is preferable to use a full-size filter module. Furthermore, it is also possible to use a pressurized module or a immersion module, but it is preferable to use a pressurized module from the viewpoint of high flow operation. In addition, an external pressure type in which the raw water is supplied from the outside of the membrane and the permeated water is obtained from the inside may be an internal pressure type in which the raw water is supplied from the inside of the membrane and the permeated water is obtained from the outside, but from the viewpoint of the simplicity of the pretreatment. It is better to press the external pressure type.

The material of the microfiltration membrane and/or the ultrafiltration membrane used in the pretreatment membrane module 20 is not particularly limited, and examples thereof include polyfluorene, polyether oxime, polyacrylonitrile, polyimine, and polyether quinone. Polyamide, polyether ketone, polyetheretherketone, polyethylene, polypropylene, ethylene-vinyl alcohol copolymer, cellulose, cellulose acetate, polyvinylidene chloride, ethylene-tetrafluoroethylene copolymer, polytetrafluoroethylene Ethylene, etc., or composite materials of these. Among them, polyvinylidene chloride Since the chemical resistance is excellent, the precision filtration membrane and/or the ultrafiltration membrane are periodically cleaned by the drug to restore the filtration function of the precision filtration membrane and/or the ultrafiltration membrane, and the length of the pretreatment membrane module is long. It is suitable for life, so it is suitable as a material for precision filtration membranes and/or ultrafiltration membranes.

The material of the casing of the pretreatment membrane module 20 may be, for example, a polyolefin such as polyethylene, polypropylene or polybutene, or a polytetrafluoroethylene (PTFE), a tetrafluoroethylene-perfluoroalkyl group or a vinyl ether copolymer ( PFA), fluorinated ethylene polypropylene copolymer (FEP), ethylene tetrafluoroethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), ethylene trifluoride-ethylene copolymer (ECTFE), polydisperse Fluorine resin such as vinyl fluoride (PVDF), chlorine resin such as polyvinyl chloride resin or polyvinylidene chloride, and polyfluorene resin, polyether oxime resin, polyallyl oxime resin, polyphenylene ether resin, Acrylonitrile-butadiene-styrene copolymer resin (ABS), acrylonitrile-styrene copolymer resin, polyphenylene sulfide resin, polyamide resin, polycarbonate resin, polyether ketone resin, polyether ether Ketone resins and the like are used singly or in combination. Further, aluminum, stainless steel, or the like is preferable to the resin, and a composite material such as a composite of a resin and a metal, a glass fiber reinforced resin, or a carbon fiber reinforced resin may be used.

Further, the reverse osmosis membrane module 9 of the reverse osmosis membrane device 10 of the present invention is obtained by concentrating a spiral element, a plate and frame type element, a tubular element using a tubular film, and a hollow type membrane. The hollow membrane element formed by the casing is connected to and received by the pressure vessel in a singular or plural series, wherein the spiral membrane is formed by a film having a flat membrane surrounding the water collection tube. The plate and frame type element is formed by attaching a flat film to both sides of the plate support plate through a spacer and stacking the layers at a certain interval. The form of the component can be For any type of person, it is preferable to use a spiral element from the viewpoint of operability and interchangeability. Further, the number of components can be arbitrarily set in accordance with the film properties. When a spiral element is used, the number of components loaded in one module is preferably one to eight in series. Further, it is also possible to arrange the reverse osmosis membrane module 9 in a plurality of parallel configurations.

The reverse osmosis membrane constituting the reverse osmosis membrane module 9 may be any one which has a chlorine removal performance, and may be used, for example, polyphthalamide or polypiperidin. A guanamine, a polyester amide, or a bridged water-soluble vinyl polymer, as a film builder, can be used for at least one side of the film having a fine layer, having a layer from the fine layer toward the inside of the film or A microporous membrane (asymmetric membrane) whose membrane surface gradually becomes larger in diameter, or a very thin separation functional layer (composite membrane) formed of other materials on the fine layer of such an asymmetric membrane. . However, in order to achieve high water production, a composite film is preferred, and in particular, a polyamine-based composite film is preferred from the viewpoints of water permeability and chemical resistance, and more preferably piperazine. Polyamide composite membrane.

For the materials of the first raw water supply pipe 2, the second raw water supply pipe 4, the first connecting pipe 6, the second connecting pipe 8, and the bypass pipe 12, a resin pipe such as a vinyl chloride pipe or a polyethylene pipe, or carbon can be used. It is possible to use either a metal pipe such as a steel pipe or a stainless steel pipe or a resin-lined inner liner in the metal pipe, but it is not necessary to consider the water quality of the raw water and the necessary pressure of the device. In particular, since the second connecting pipe 8 is mostly high-pressure, it is preferable to use a metal pipe or a liner pipe instead of a resin pipe.

As the raw water supply pump 3, a turbo pump is generally used, and as the high pressure pump 7, a turbo pump or a plunger pump is generally used.

As the raw water supply unit, a raw water tank 1 can be exemplified. As the material of the raw water tank 1, it may be any of mixed soil or a resin tank such as polyethylene, polypropylene, or FRP. In addition, when the water is directly taken from the sea, the river, the water well or the like as the object, there is a case where the raw water tank 1 is not provided.

In order to explain the backwashing step of the processing apparatus 5 before the present invention, an example of a schematic diagram of the processing apparatus 5 before the film module is used is shown in FIG. The pretreatment apparatus 5 is provided with a pretreatment membrane module 20, a raw water supply pump 21 provided in the second raw water supply pipe 4, a filter pipe 22 provided in the first connection pipe 6 on the pretreatment water side, and a filter pipe 22 provided in the backwash pipe 26. The backwash valve 23, the backwash drain valve 24 provided in the backwash drain pipe 27, and the backwash pump 25 through the backwash pipe 26 for supplying the backwash water. Others include piping for air cleaning, pumps, piping for pumping air, pumps, and the like. Further, the sand filter device has the same structure, but the present invention will be described later using the pretreatment device 5 using the membrane module as a mode.

In the present invention, the pretreatment device 5 and the reverse osmosis membrane device 10 are directly connected without passing through an intermediate tank or the like, and the pretreatment device 5 is periodically transferred from the filtration step to the backwashing step and is isolated from the operation series, so that although it is in the second Although not shown in the drawings, the same pretreatment membrane module 20 must be a plural series.

The backwashing step which is periodically performed to suppress the increase in the filtration resistance of the pretreatment membrane module 20 is carried out as follows. The pretreatment membrane module 20 of a part of the plurality of pre-process membrane modules 20 connected in parallel and independently filters the raw water while supplying the raw water to the pump 21 and filtering for the remaining pretreatment membrane module 20 to be subjected to the backwashing step. The valve 22 is set to be closed to stop the filtration, and the backwash valve 23 and the backwash drain valve 24 are opened and stored in the pretreatment membrane. The pretreatment water of the water tank is supplied to the pretreatment water side of the pretreatment membrane module 20 by the backwash pump 25. Pretreatment water or the like can be used as the backwash water. The backwash water that has passed through in the opposite direction to the pretreatment membrane is passed through the backwash drain valve 24 that is opened, and is discharged as a washing drain from the pretreatment membrane module 20 to be a backwashing step. After the backwash for a given time, the backwash pump 25 is stopped and the backwash valve is set to off.

Simultaneously with or after the backwashing, it is not shown in the drawings, but an air washing step of supplying pressurized air to the lower portion of the pretreatment membrane module 20 and washing the pretreatment membrane may be performed.

After the backwashing, although not shown in the drawing, the washing drain held on the raw water side of the pretreatment membrane module 20 is opened from the pretreatment membrane mold by opening the drain valve provided at the lower portion of the pretreatment membrane module 20. Group 20 is discharged.

By supplying the flow control valve 32 and the raw water supply valve 21 to the opening, the raw water is supplied to the pretreatment membrane module 20 that has finished the backwashing, and the stagnant flow is sucked from the open backwashing drain valve 24 to the pretreatment membrane module 20. The air on the raw water side. In this step, a flashing step of discharging the washing drainage remaining on the raw water side of the pretreatment membrane module 20 through the backwashing drain valve 24 may be applied, and at this time, the washing drainage may be drained from the drain. The valve is discharged or not discharged. After the air is withdrawn from the backwash drain valve 24, the backwashing drain valve 24 is closed, and the filter valve 22 is opened to end the backwashing step of the pretreatment membrane module 20, and the pretreatment membrane module having the backwashing step is implemented. Group 20 returns to the filtration step in the same manner as the other pretreatment membrane modules 20.

In the present invention, as described above, the pretreatment apparatus 5 includes a plurality of series shown in FIG. 2, and periodically repeats from the filtration step to the backwashing step in each series, and returns to the end of the backwashing step. To the filter step Step. When this step is transferred, the pressure in the system will change due to the increase or decrease in the number of operating series. When this pressure fluctuation is large, the reverse osmosis membrane device 10 is shut down due to the interlocking of the supply pressure of the high pressure pump 7, which has a large influence on the flow rate control of the permeable membrane device 10. Therefore, minimizing this pressure fluctuation is a preferable operating condition for the direct connection operation of the pretreatment apparatus 5 and the permeable membrane apparatus 10.

As described above, in the method for producing fresh water for producing fresh water from raw water by the fresh water producing apparatus of the present invention, as shown in Fig. 1, the reverse osmosis membrane is controlled by the backwashing step of the pretreatment apparatus 5. The pressure control unit 14 that supplies the pressure is controlled to be disposed on the first connecting pipe 6 by using the pressure control valve 13 that is disposed on the bypass pipe 12 that is branched in the second raw water supply pipe 4 and that discharges the raw water to the outside of the system. The pressure gauge 11 measures the treated water pressure of the pretreated water.

When a part of the series including the plurality of series of pretreatment apparatuses 5 is transferred from the filtration step to the backwashing step, the supply pressure of the treated water is decompressed before being supplied to the high pressure pump 7 due to the decrease in the number of operation series, but the fresh water manufacturing apparatus of the present invention and In the method for producing fresh water according to the present invention, the pressure control unit 14 automatically turns the pressure control valve 13 in the closing direction to adjust the pressure in the system to be constant. On the other hand, when the series of the backwashing steps in the pretreatment apparatus 5 is returned to the filtering step, the supply pressure of the treated water is increased before the supply to the high pressure pump 7 due to the increase in the number of operating series, but the fresh water manufacturing apparatus of the present invention is borrowed. The pressure control unit 14 automatically turns the pressure control valve 14 into the opening direction to adjust the pressure in the system to be constant.

The fresh water producing apparatus of the present invention, as shown in Fig. 3, is preferably a form other than the configuration of the fresh water producing apparatus shown in Fig. 1 described above. Further, the second raw water supply pipe 4 further includes a flow meter 31 that measures the flow rate of the raw water supplied to each series of the pretreatment device 5, and a flow rate control valve 32 that controls the flow rate of the raw water supplied to each series of the pretreatment device 5. .

In the final stage of the backwashing step, when the pretreatment apparatus 5 is a membrane module as described above, the raw water is supplied and the air remaining on the raw water side of the treatment membrane module 20 is discharged from the backwash drain valve 24. Further, when the pretreatment device 5 is a sand filter device, in the final stage of the backwashing step, as the positive washing step, in order to stabilize the filter material for a certain period of time after the backwashing, it is necessary to supply raw water and wash the drain valve or the like from the backwashing valve. discharge.

In any case, it is connected to the other series that continue to operate, and the raw water is supplied from the second raw water supply pipe 4 that maintains the predetermined pressure, and the pretreatment device 5 that performs the backwashing step passes through the backwash drain valve 24 and the reverse The drain pipe 27 is drained and discharged to the drain side in which the outside of the system is open to the atmosphere. Therefore, a large amount of raw water temporarily flows to the pretreatment device 5 in which the backwashing step is performed, and the pressure in other systems that continue to operate is significantly decompressed. .

Then, in the method for producing fresh water for producing fresh water from raw water by the fresh water producing apparatus of the present invention, the configuration shown in Fig. 3 is characterized in that when the raw water must be supplied to the pretreatment device 5 in the backwashing step. The flow control unit 33 that controls the flow rate of the raw water supplied to the pretreatment device 5 and the flow rate control valve 32 that controls the flow rate of the raw water supplied to each series of the pretreatment device 5 are used to control the respective series for the pretreatment device 5. The set flow meter 31 measures the raw water flow rate supplied to each series of the pretreatment device 5.

Flowing the raw water supply amount in the backwashing step as described above The amount control reduces the pressure of the other series of raw water supply pipes 4 that continue to operate, and supplies the raw water to the pretreatment apparatus 5 in the backwashing step.

Further, the raw water flow rate control in the pretreatment apparatus 5 in the backwashing step using the flow meter 31 and the flow rate control valve 32 may be used for the raw water flow rate control in the pretreatment apparatus 5 in the filtration step, only before The reverse osmosis membrane device 10 in the subsequent stage of the treatment device 5 generally also controls the flow rate of the treated water before being supplied to the reverse osmosis membrane device 10. In this case, the flow rate control is connected in series, and the control effects are divergent due to the interference effects of the respective controls. Therefore, the raw water flow rate control system of the processing apparatus 5 of the present invention is used only for the raw water supply in the backwashing step, the flow rate control is not performed during the filtration step, and it is preferable to use the flow rate control valve 32 to be fully opened. .

The pressure gauge 11 is preferably an electronic pressure transmitter. Moreover, the material of the liquid contact portion is selected in consideration of the raw water quality in the same manner as the material of the piping of the first connecting pipe 6.

The pressure control valve 13 and the flow control valve 32 may be any of an electrically operated valve and an air actuated valve. However, in consideration of reactivity, it is preferable to use an air actuating valve having a positioner. The valve body is generally a globe valve, a butterfly valve, or the like.

The pressure control unit 14 and the flow rate control unit 33 are generally PID controlled, and may be controlled by using a PID control function of a PLC or DCS that controls the entire fresh water production apparatus, or by newly using a PID single-loop controller.

Furthermore, in order to change the pressure when the steps of the pretreatment device 5 are shifted The reduction is preferably such that the switching speed of the raw water supply pump 21 for the transfer of the steps and the filter valve 22 provided on the pretreated water side is moderated as much as possible. Therefore, when the raw water supply pump 21 and the filter valve 22 are of the air type, it is preferable to provide a speed controller or a positioner.

As described above, since the supply pressure to the reverse osmosis membrane device 10 can always be constant, it is not necessary to stop the reverse osmosis membrane device 10 and does not affect the flow rate control of the reverse osmosis membrane device 10, and can be stably operated. Reverse osmosis membrane device 10.

The present invention has been described in detail with reference to the particular embodiments of the invention, and various modifications and changes can be made without departing from the spirit and scope of the invention.

The present patent application is based on Japanese Patent Application No. 2011-201349, filed on Sep. 15, 2011, and Japanese Patent Application No. 2012-05839.

1‧‧‧ original sink

2‧‧‧1st raw water supply piping

3‧‧‧ Raw water supply pump

4‧‧‧2nd raw water supply piping

5‧‧‧Pre-treatment device

6‧‧‧1st connection piping

7‧‧‧High pressure pump

8‧‧‧2nd connection piping

9‧‧‧ reverse osmosis membrane module

10‧‧‧ reverse osmosis membrane device

11‧‧‧ pressure gauge

12‧‧‧Bypass piping

13‧‧‧Pressure control valve

14‧‧‧ Pressure Control Department

15‧‧‧Intermediate trough

16‧‧‧ booster pump

20‧‧‧Pretreatment membrane module

21‧‧‧ Raw water supply valve

22‧‧‧Filter valve

23‧‧‧Backwash valve

24‧‧‧Backwash drain valve

25‧‧‧Backwash pump

26‧‧‧Backwashing piping

27‧‧‧Backwash drainage piping

31‧‧‧ Flowmeter

32‧‧‧Flow control valve

33‧‧‧Flow Control Department

Fig. 1 is a schematic flow chart showing an apparatus of an example of the fresh water producing apparatus of the present invention.

Fig. 2 is a schematic view showing an example of a processing apparatus before the use of the membrane module of the present invention.

Fig. 3 is a schematic flow chart showing the apparatus of another example of the fresh water producing apparatus of the present invention.

Fig. 4 is a schematic view showing another example of the processing apparatus before the film module of the present invention is used.

Fig. 5 is a schematic flow chart showing an example of a conventional fresh water producing apparatus.

1‧‧‧ original sink

2‧‧‧1st raw water supply piping

3‧‧‧ Raw water supply pump

4‧‧‧2nd raw water supply piping

5‧‧‧Pre-treatment device

6‧‧‧1st connection piping

7‧‧‧High pressure pump

8‧‧‧2nd connection piping

9‧‧‧ reverse osmosis membrane module

10‧‧‧ reverse osmosis membrane device

11‧‧‧ pressure gauge

12‧‧‧Bypass piping

13‧‧‧Pressure control valve

14‧‧‧ Pressure Control Department

31‧‧‧ Flowmeter

32‧‧‧Flow control valve

33‧‧‧Flow Control Department

Claims (5)

A fresh water manufacturing device comprising: a pretreatment device comprising a plurality of series of pretreated water for treating raw water; a reverse osmosis membrane device for treating the pretreated water to produce fresh water; and a raw water supply pump The raw water is supplied to the pretreatment device; the high pressure pump supplies the pretreated water to the reverse osmosis membrane device; the first raw water supply pipe is connected to the raw water supply unit at one end and to the raw water supply pump at the other end; the second raw water The supply pipe is connected to the raw water supply pump at one end and to the respective series of the pretreatment device at the other end; the first connecting pipe is connected at one end to each series of the pretreatment device and at the other end to the high pressure pump; The second connecting pipe is connected to the high pressure pump at one end and to the reverse osmosis membrane device at the other end; wherein the fresh water producing device further includes a pressure gauge provided on the first connecting pipe and measuring the supply to the high pressure pump The treated water pressure of the pretreated water; the bypass pipe is branched on the second raw water supply pipe and the raw water is discharged to the outside of the system; and the pressure control valve Lines disposed on the bypass piping and controlling the process pressure. The fresh water producing apparatus according to the first aspect of the invention, wherein the second raw water supply pipe has a measurement supply to the front side a flow meter for the raw water flow of each series of the device; and a flow control valve for controlling the flow rate of the raw water supplied to each series of the foregoing pretreatment device. A method for producing fresh water, which is a method for producing fresh water from raw water by the fresh water producing apparatus of claim 1 or 2, comprising: using the aforementioned pressure gauge and the pressure control valve to cause the water pressure to be treated Controlled in a certain way. A method for producing fresh water, which is a method for producing fresh water fresh water from raw water by the fresh water producing apparatus of the second aspect of the patent application, the manufacturing method comprising the backwashing step of the foregoing processing apparatus, and using the foregoing flow meter and the foregoing The flow rate control valve controls the flow rate of the raw water supplied to the pretreatment device in the backwashing step to be constant. The method for producing fresh water according to the fourth aspect of the invention, wherein the pressure gauge is controlled to be constant by using the pressure gauge and the pressure control valve.