WO2014045804A1

WO2014045804A1 - Water purification device and method for manufacturing purified water

Info

Publication number: WO2014045804A1
Application number: PCT/JP2013/072726
Authority: WO
Inventors: 丸木　祐治
Original assignee: 株式会社タカギ
Priority date: 2012-09-19
Filing date: 2013-08-26
Publication date: 2014-03-27
Also published as: JP2014057926A

Abstract

[Problem] To provide technology for increasing backwashing efficiency in a water purification device provided with membrane modules and a method for manufacturing purified water using the same. [Solution] This water purification device is characterized by being provided with: a raw water supply path; a raw water supply means that is disposed in the raw water supply path and feeds the raw water; a plurality of raw water branch paths that branches the raw water supply path into at least two or more branches; a plurality of membrane modules that is disposed in the plurality of raw water branch paths and purify the raw water; an elimination pathway connected on the upstream side of a membrane means that is provided in the plurality of membrane modules and purifies the raw water; a plurality of purified water branch paths connected to the downstream side of the plurality of membrane modules; and a purified water path into which the plurality of purified water branch paths is combined.

Description

Water purification device and water purification method

The present invention relates to a water purifier and a method for producing purified water.

In recent years, small water purifiers for the purpose of removing residual chlorine (hypochlorous acid), musty odor, turbidity, microorganisms and the like from tap water have become widespread. In these water purifiers, residual chlorine in tap water, activated carbon that removes off-flavors and odors, ceramic filters, microfiltration membranes that remove turbidity and microorganisms, hollow fiber membranes, and the like were used. When such a water purifier is provided in a residence or the like, it is often installed under a kitchen faucet or sink, and tap water has been purified to be suitable for drinking and cooking.

On the other hand, there was a need to use purified tap water in the entire area of buildings such as buildings and hotels, or to purify well water and use it in the entire area of the building. Installing the vessel is cumbersome. Therefore, a water purification system that attaches a large water purification device to an entrance for introducing tap water or the like into a building, purifies the tap water collectively, and supplies the entire building to water has begun to spread. These large water purifiers are also composed of activated carbon, ceramic filters, microfiltration membranes, etc., just like small water purifiers. By passing these, residual chlorine and turbidity in tap water are removed, and a plurality of water purifiers in the building are removed. Supply purified water to the place where it is used.

As such a large water purification apparatus, a filtration apparatus using a membrane module is known (for example, Patent Documents 1 to 3). In Patent Document 1, a plurality of membrane modules, an introduction line for introducing a stock solution to the primary side of each of the membrane modules, and a secondary side of each of the membrane modules are connected and filtered by the membrane module. A filtration liquid discharge line for discharging the filtrate, and at the time of backwashing, the flow path of the introduction line communicating with the membrane module to be backwashed is provided in the introduction line in a filtration device that is closed A filtrate supply pump for supplying a filtrate at a predetermined flow rate to the membrane module; a filtrate pump for pumping the filtrate while being provided in the filtrate discharge line; and a filtrate pump for the filtrate discharge line And a flow path between the downstream side of the membrane module and the secondary side of each of the membrane modules, and the membrane module to be backwashed during backwashing. The flow path from the membrane module to be backwashed during backwashing is opened and connected to the primary side of each of the membrane modules and the backwash line through which the filtrate flows as backwashing liquid. A cleaning liquid discharge line through which the backwash liquid that has passed through the membrane module is discharged, pressure detection means for detecting the pressure of the filtrate on the suction side of the filtrate pressure feed pump, and detected by the pressure detection means And a control means for controlling the drive of the filtrate pumping pump based on the pressure.

In Patent Document 2, in a method of operating a membrane separation apparatus having a plurality of membrane modules having a common permeate line, the permeate from other membrane modules is used when backwashing is performed in some membrane modules. There is disclosed a method of operating a membrane separation device, characterized in that it is supplied to the secondary side of the membrane module to be backwashed by the discharge pressure and then pressurized gas is supplied to the secondary side.

Patent Document 3 discloses that in a membrane filtration apparatus including a plurality of membrane modules, a membrane passage that performs backwashing is directly passed with membrane permeated water obtained from another membrane module and backwashed. Equipped with a fluid passage switching mechanism for switching, a compressor and air piping for supplying pressurized air to each membrane module, stops the introduction of raw water into the membrane module performing backwashing, and instead pressurizes from the compressor Introduce air to the primary side of the membrane module for backwashing and introduce permeated water from other membrane modules to the secondary side of the membrane module for backwashing to perform backwashing or backwashing. A membrane filtration device configured to supply pressurized air to the secondary side of a membrane module that performs washing, mix in backwash water, and backwash with a gas-liquid mixed fluid. The main pipe is connected, and the raw water main pipe Branch pipes are branched, the end side of each raw water branch pipe is connected to the raw water inlet of each membrane module, each raw water branch pipe is provided with an open / close valve, and the concentrated water outlet of each membrane module is connected via the pipe The three-way valve is connected to an inflow port of the three-way valve, and each of the three-way valves has two outflow ports. One of the outflow ports is connected to a branch pipe for circulating the concentrated water. Connected to the main pipe, one end of the branch pipe for backwash drainage is connected to the other outflow port of the three-way valve, and the other end of the branch pipe is connected to the main pipe for backwash drainage discharge One end of a branch pipe for extracting permeate is connected to the permeate outlet of the membrane module, and the other end of the branch pipe is connected to a main pipe for extracting permeate, Raw water branch piping The end side of the air branch pipe is connected to the portion between each on-off valve and each membrane module, the upstream end side of each air branch pipe is connected to the air main pipe, and this air main pipe is connected to the compressor. A membrane filtration device characterized by this is disclosed.

JP 2011-177653 A JP 2001-190935 A Japanese Patent No. 4178178

When a filtration device that uses a membrane module as the filtration means is continuously used, foreign matter is clogged in the filtration membrane provided in the membrane module, and the filtration efficiency is lowered. In order not to lower the filtration efficiency of the membrane module of the filtration device, it is necessary to back-wash the membrane module. However, in the conventional filtration device, it cannot be said that the back-washing efficiency is sufficient. Moreover, in order to install a filtration apparatus in buildings such as buildings and hotels, it is required to reduce the size of the filtration apparatus.
This invention is made | formed in view of the said situation, Comprising: It aims at providing the novel water purifier with high backwashing efficiency, and the manufacturing method of the purified water using the same. Moreover, this invention makes it the further subject to size reduction of the large water purification apparatus which supplies purified water to the whole buildings, such as a condominium and a building.

The water purifier of the present invention includes a raw water supply channel, a raw water supply unit that is disposed in the raw water supply channel, and that feeds raw water, a plurality of raw water branch channels that branch the raw water supply channel into at least two, A plurality of membrane modules that are disposed in the raw water branch path and that purify the raw water, a discharge path that is connected upstream of the membrane means that purifies the raw water included in the plurality of membrane modules, and a downstream side of the plurality of membrane modules And a plurality of water purification branches and the water purification paths where the plurality of water purification branches merge.

Preferably, the discharge path is provided with a discharge valve that opens and closes the discharge path, and the raw water branch path is provided with an inflow valve that opens and closes the flow path of the raw water branch path.

The membrane module includes a raw water area to which raw water is supplied, a membrane means for purifying the raw water, and a purified water area from which purified water purified by the membrane means flows out, and the discharge path is in the raw water area of the membrane module. It is preferable that they are connected. Examples of the membrane means include a microfiltration membrane and an ultrafiltration membrane. Moreover, the said discharge path may be connected to the raw | natural water branch path downstream of the inflow valve which opens and closes the flow path of a raw | natural water branch path.

The water purifier of the present invention preferably has an inverter control unit for controlling the raw water supply means so as to pulsate the water pressure of the raw water. It is preferable that a flow path including microbubble generating means is formed in parallel in the water purification branch.

The water purifier of the present invention preferably includes a raw water tank and means for supplying a chemical solution to the raw water tank.

In the water purification method of the present invention, during normal filtration operation, raw water is supplied in parallel to a plurality of membrane modules having at least a first membrane module and a second membrane module, and the raw water is filtered through the plurality of membrane modules. In the reverse cleaning operation, the raw water is supplied to one of the first membrane module or the second membrane module while pulsating the water pressure of the raw water, the raw water is filtered, and at least a part of the obtained purified water is reversed. As washing water, the other membrane module is backwashed from the downstream side to the upstream side of the other membrane module, and the other membrane module is backwashed.

At the time of backwashing operation, raw water is supplied to the first membrane module while pulsating the water pressure of the raw water and filtered, and at least a part of the obtained purified water is used as backwash water from the downstream side of the second membrane module. Back flow to the side, back washing the second membrane module, supplying raw water to the second membrane module while pulsating the water pressure of raw water, filtering, and backwashing at least a part of the purified water obtained It is preferable to back-wash the first membrane module as water by flowing backward from the downstream side of the first membrane module to the upstream side.

Further, during the reverse cleaning operation, the raw water may be pulsated so that the ratio (Pmax / Pmix) of the maximum pressure value Pmax to the minimum pressure value Pmin of the raw water water pressure is 1.3 or more and 2.5 or less. preferable.

The water purification apparatus of the present invention can be suitably used for the method for producing water purification of the present invention.

According to the present invention, a water purifier with high backwashing efficiency can be obtained. The water purifier of the present invention can be reduced in size. According to the method for producing purified water of the present invention, purified water having excellent hygiene can be stably provided.

It is a figure which shows typically the water purifier of one Embodiment of this invention. It is a figure which shows typically the water purifier of another embodiment of this invention. It is a figure which shows typically the water purifier of another embodiment of this invention. It is a disassembled perspective view of the fluid discharge pipe structure which is a microbubble generator. It is a perspective view of the fluid discharge pipe structure which is a microbubble generator. It is a longitudinal cross-sectional view of the fluid discharge pipe structure which is a microbubble generator. It is explanatory drawing which shows many each rhombus convex part with the regularity of the shaft body for a flip-flop phenomenon generation | occurrence | production. It is explanatory drawing which shows the rhombus convex part of the shaft body for flip-flop phenomenon generation | occurrence | production. It is explanatory drawing of the spiral blade formed in a spiral blade main body. It is a figure which shows the water flow state at the time of the normal filtration driving | operation of the water purifier of embodiment. It is a figure which shows the water flow state at the time of the reverse washing operation | movement of the water purifier of embodiment. It is a graph which shows the pressure change of the raw | natural water supplied to a membrane module. It is a figure which shows the water flow state at the time of the reverse washing operation | movement of the water purifier of embodiment. It is a front view of the water purifier of one embodiment of the present invention. It is a right view of the water purifier of FIG. It is a left view of the water purifier of FIG. It is a rear view of the water purifier of FIG. It is a top view of the water purifier of FIG. It is a bottom view of the water purifier of FIG. It is a flowchart of the water purifier of FIG.

(1) Water purifier First, the water purifier of the present invention will be described with reference to the drawings. FIG. 1 is a diagram schematically showing the configuration of the water purifier of the present invention. The water purifier 1 of the present invention is disposed in the raw water supply path 3, the raw water supply path 3, and the raw water supply means P1 that feeds the raw water, and a plurality of raw water branch paths that branch the raw water supply path 3 into at least two or more. 5A, 5B, and a plurality of

membrane modules

9A, 9B that are disposed in the plurality of raw

water branch paths

5A, 5B and purify the raw water, and upstream of the membrane means 9c that purifies the raw water included in the

membrane modules

9A, 9B. The

discharge paths

7A and 7B to be connected, the plurality of water

purification branch paths

11A and 11B connected to the downstream side of the plurality of

membrane modules

9A and 9B, and the water purification path 13 where the plurality of water

purification branch paths

11A and 11B merge. It is characterized by providing. In the present invention, the side to which raw water is supplied (left side in FIG. 1) is referred to as the upstream side, and the side from which purified water is discharged (right side in FIG. 1) is referred to as the downstream side.

The raw water supply path 3 supplies raw water to be subjected to purification treatment such as tap water and well water. The raw water supply channel 3 may be directly connected to a water main supplied to a building such as an apartment, an apartment, a building, a hotel, or a plurality of detached houses, or a raw water for storing tap water from the water main. You may connect to the aquarium. The raw water supply path 3 is constituted by a pipe line having a predetermined pipe diameter. The raw water supply path 3 preferably includes an inflow valve (first valve V1) for opening and closing the raw water supply path 3. For example, the inflow valve may be a check valve.

In the raw water supply path 3, raw water supply means P1 for sending raw water is disposed. Examples of the raw water supply means P1 include a vertical multi-stage centrifugal pump, a horizontal multi-stage centrifugal pump, and a positive displacement pump. Among these, it is preferable to use a vertical multistage centrifugal pump as the raw water supply means P1 because the raw water is stably pressurized and fed.

The downstream end of the raw water supply path 3 is connected at the branch point 4 to the upstream ends of the raw

water branch paths

5A and 5B that branch the raw water supply path 3 into a plurality. The raw

water branch paths

5A and 5B are constituted by pipe lines having a predetermined pipe diameter. The raw

water branch paths

5A and 5B include inflow valves (second valve V2 and third valve V3) for opening and closing the raw

water branch paths

5A and 5B, respectively. The downstream ends of the raw

water branch paths

5A and 5B are connected to

membrane modules

9A and 9B that purify the raw water.

The

membrane modules

9A and 9B remove foreign matters such as fine particles and turbidity in the raw water, purify the raw water, and discharge the purified water. The

membrane modules

9A and 9B include membrane means 9c for purifying raw water, and a substantially cylindrical container 9d for housing the membrane means 9c. In the

membrane module

9A, 9B, the raw water region 9e to which raw water is supplied and the purified water purified by the membrane means flow in between the membrane means 9c for purifying the raw water inside the substantially cylindrical container 9d. It is preferable to provide the purified water area 9f.

Examples of the membrane means 9c included in the

membrane modules

9A and 9B include a reverse osmosis membrane (RO membrane), a nanofiltration membrane (NF membrane), a microfiltration membrane (MF membrane), and an ultrafiltration membrane (UF membrane). A filtration membrane can be mentioned. The reverse osmosis membrane (RO membrane) has a high water flow pressure during filtration, so that the raw water supply means P1 needs to have high performance or a large size. In addition, the power cost during operation may be high, and the amount of water used is also high because waste water is required. Therefore, from the viewpoint that raw water can be filtered at a relatively low pressure and at a low cost, the membrane means 9c included in the membrane module includes a nanofiltration membrane (NF membrane), a microfiltration membrane (MF membrane), and an ultrafiltration membrane. (UF membrane) is preferable, a microfiltration membrane (MF membrane) and an ultrafiltration membrane (UF membrane) are more preferable, and an ultrafiltration membrane (UF membrane) is more preferable. The

membrane modules

9A and 9B may be either an external pressure type or an internal pressure type, and preferably an internal pressure type.

The

membrane modules

9A and 9B are provided with a raw water inlet 9g and a purified water outlet 9h, and further with a concentrated water outlet 9i for discharging concentrated water. The raw water inlet 9g and the concentrated water outlet 9i are connected to the raw water area 9e of the

membrane modules

9A and 9B, and the purified water outlet 9h is connected to the purified water area 9f of the

membrane modules

9A and 9B.

The water purifier of the present invention has a discharge path connected to the upstream side of the membrane means 9c included in the membrane module. The discharge path is a flow path for discharging the backwash water when the membrane module is mainly backwashed. The said discharge path should just be connected to the upstream of the membrane means 9c with which

membrane module

9A, 9B is equipped, for example, the aspect connected to the raw | natural water area | region 9e of

membrane module

9A, 9B, it connects with raw |

natural water branch

5A, 5B Or a mode of connecting to both the raw water region 9e of the

membrane modules

9A and 9B and the raw

water branch paths

5A and 5B.

1, one ends of the

discharge paths

7A and 7B are connected to the concentrated water discharge ports 9i of the

membrane modules

9A and 9B. The

discharge passages

7A and 7B are preferably composed of pipe passages having a predetermined pipe diameter, and are provided with valves (fourth valve V4 and fifth valve V5) for opening and closing the respective passages. The

discharge paths

7A and 7B may further merge.

FIG. 2 shows a modification of the aspect in which the discharge path is provided. The water purification apparatus 1 of the aspect shown in FIG. 2 includes

discharge paths

7A and 7B connected to the raw water areas 9e of the

membrane modules

9A and 9B, and

discharge paths

15A and 15B connected to the raw

water branch paths

5A and 5B. In such an embodiment, the backwash water can be discharged from any of the

discharge paths

7A and 7B or the

discharge paths

15A and 15B. The

discharge passages

15A and 15B are each configured by a pipe passage having a predetermined pipe diameter, and are provided with discharge valves (sixth valve V6 and seventh valve V7) for opening and closing the discharge passage. The

discharge paths

15A and 15B are connected to the raw

water branch paths

5A and 5B on the downstream side of the inflow valves (second valve V2 and third valve V3) of the raw

water branch paths

5A and 5B, respectively.

The upstream ends of the purified

water branch paths

11A and 11B are connected to the downstream side of the

membrane modules

9A and 9B. The purified

water branch paths

11A and 11B are connected to the purified water discharge port 9h of the

membrane modules

9A and 9B. The downstream sides of the purified

water branch paths

11A and 11B are formed so that the purified

water branch paths

11A and 11B connected at the junction 17 and connected to the plurality of membrane modules communicate with each other. By connecting the purified water branch paths 11 A and 11 B, the purified water discharged from one membrane module can be made to flow backward to the other membrane module.

The

raw water branch

5A and 5B are preferably provided with

pressure gauges

14A and 14B for measuring the pressure of the raw water flowing in the raw water branch. Moreover, it is preferable that the

pressure gauges

16A and 16B which measure the pressure of the purified water which flows through the inside of the purified water branch are provided in the purified

water branches

11A and 11B.

The purified water path 13 is connected to the junction 17 of the purified

water branch paths

11A and 11B. The water purification channel 13 is provided with a valve (eighth valve V8) for opening and closing the water purification channel 13. The water purification path 13 is composed of a pipe having a predetermined pipe diameter. It is preferable that the purified water path 13 is provided with a purified water discharge path 19 for discharging purified water. The purified water discharge path 19 is constituted by a pipeline having a predetermined pipe diameter, and includes a valve (a ninth valve V9) for opening and closing the purified water discharge path 19.

In the embodiment of FIGS. 1 and 2, the membrane module has been described based on the form having the first membrane module and the second membrane module, but the membrane module is not particularly limited as long as it is 2 or more. For example, the aspect which has two or more pairs of membrane module sets which consist of a 1st membrane module and a 2nd membrane module can be mentioned. Since the water purifier of the present invention has a plurality of pairs of membrane module sets each composed of a first membrane module and a second membrane module, the amount of raw water treated can be increased.

1 and 2, the purified water obtained from one membrane module in a filtered state is configured to be used as backwash water for another membrane module to be backwashed. That is, the ratio of the number of membrane modules in a filtered state to the membrane module to be backwashed is 1: 1. However, the purified water obtained from a plurality of membrane modules in a filtered state may be merged and used as backwash water for one membrane module to be backwashed, or 1 in a filtered state. You may comprise so that the purified water obtained from one membrane module may be branched and used as the backwash water of the several membrane module used as the backwash object. However, in the case of membrane module in filtration state: membrane module to be backwashed = multiple: 1, the pressure of backwashing water becomes too high, and there is a risk of damaging the filtration membrane provided in the membrane module to be backwashed . On the other hand, when the membrane module in the filtered state: the membrane module to be backwashed = 1: many, the pressure of backwashing water is lowered, so that the backwashing efficiency may be lowered. Therefore, it is preferable that the ratio of the number of membrane modules in a filtered state and the number of membrane modules to be backwashed is 1: 1.

The water purifier 1 of the present invention preferably includes a control means 21. The control means 21 preferably includes, for example, an inverter control unit 23, a valve control unit 25, a membrane differential pressure calculation unit 27, a display 29, a manual switch 31, a timer 33, and the like.

It is particularly preferable that the water purifier 1 of the present invention has an inverter control unit 23 that controls the raw water supply means P1. It is preferable to control the raw water pressure supplied by the raw water supply means by controlling the raw water supply means P1 with an inverter. For example, the inverter control unit 23 controls the raw water supply means P1 so that the pressure of the raw water becomes substantially constant during the normal filtration operation, and controls the raw water supply means P1 so that the pressure of the raw water pulsates during the reverse cleaning operation. To do.

The membrane differential pressure calculation unit 23 receives the measurement values of the pressure gauges 14A, 14B, 16A, and 16B, and calculates the pressure difference between the

membrane modules

9A and 9B. For example, according to the pressure difference data, the membrane differential pressure calculation unit 23 instructs the valve control unit 25 to switch the valve so that the normal filtration operation or the reverse cleaning operation is performed.

The valve control unit 25 opens and closes the valve based on manual switch operation data, membrane differential pressure data supplied by the membrane differential pressure calculation unit, time data supplied by a timer, and the like. The valve controller and each valve are preferably connected by wire or wirelessly.

For example, the timer measures the time of normal filtration operation and the time of backwash operation, and when each operation time reaches a predetermined time, the valve control unit 25 performs normal filtration operation or backwash operation. In addition, the switching of the valve can be instructed.

The display can display, for example, the pressure value received from the pressure gauge, the membrane differential pressure, the current operation process, and the like.

FIG. 3 shows another embodiment of the water purifier of the present invention. It is also preferable that the water purifier 1 of the present invention includes means for supplying a chemical solution to purified water or raw water. Examples of the means for supplying the chemical liquid include a chemical liquid tank and a pump for supplying the chemical liquid. For example, the water purifier 1 of the present invention includes a raw water tank 35, a chemical liquid tank 37 for supplying a chemical liquid such as a nucleating agent, a flocculant, or a pH adjuster to the raw water tank 35, and the chemical liquid as a raw material. It is preferable to have a pump P3 for supplying to the water tank 35. With such a configuration, in the raw water tank 35, impurities such as charged metal ions, arsenic, fluorine, silica, and chlorine contained in the raw water can be aggregated. The obtained agglomerates are supplied to the membrane module together with the raw water, and are removed as foreign substances by the membrane means. The water purifier 1 of the present invention may include a plurality of chemical tanks. In particular, it is preferable to include a chemical tank that stores a nucleating agent or a flocculant and a chemical tank that stores a pH adjuster. Such a configuration facilitates adjustment to a pH range in which the nucleating agent or the flocculant has a high working efficiency.

Moreover, it is preferable that the water purifier 1 of this invention has the chemical | medical solution tank 41 for adding chemical | medical solutions, such as hypochlorous acid and sodium hypochlorite, to the purified water, and the pump P2 for sending a chemical | medical solution. . In FIG. 3, the purified water obtained by the water purification apparatus 1 of the present invention is shown to be supplied to the water receiving tank 45, but the water receiving tank 45 is not necessarily required.

It is also preferable that the raw water tank 35 and the water receiving tank 45 include level meters L1 and L2. For example, based on the water level data of the raw water tank 35 measured by the level meter L1, the valve control unit 25 switches the valve so that the normal filtration operation and the reverse cleaning operation are switched when a certain amount of raw water is processed. You may be instructed.

As shown in FIG. 3, it is also preferable that the water purifier 1 of the present invention includes

microbubble generators

47A and 47B in parallel with the

water purification branches

11A and 11B. By setting it as such a structure, a microbubble can be mixed in backwash water at the time of backwash operation. The

microbubble generators

47A and 47B are connected in parallel to the purified

water branch paths

11A and 11B via, for example, three-way valves 49A and 49B and

pipe lines

48A and 48B having a predetermined pipe diameter. When using three-way balf 49A, 49B to back flow backwash water only in the purified

water branch

11A, 11B, backflow water back in parallel to the purified

water branch

11A, 11B and the

microbubble generators

47A, 47B In addition, it is possible to select a case where the backwash water is caused to flow backward only through the

microbubble generators

47A and 47B. By adopting the configuration shown in FIG. 3 as a configuration including the microbubble generator, the size and cost of the device can be reduced. On the other hand, when expanding the control range of the supply amount of microbubbles or improving the accuracy of the supply amount, water is supplied to the

microbubble generators

47A and 47B from another water supply flow path to generate microbubbles. You may make it supply the backwash water containing the microbubble derived | led-out from

apparatus

47A, 47B through the flow path which connects the purified

water branch path

11A, 11B from

microbubble generator

47A, 47B.

Examples of the method for generating microbubbles include a pore method, a pressure dissolution method, an ultrasonic method, a gas-liquid mixing / shearing method, an ultra-high speed swirling method, and a flip-flop phenomenon generating method. Among these, since it is easy to install in the water purifier 1 of this invention, it is preferable to employ | adopt a super-high-speed turning system, a flip-flop phenomenon generation system, etc.

As the microbubble generator used in the water purifier 1 of the present invention, for example, a fluid discharge ring structure as disclosed in Japanese Patent No. 3835543 is preferable. The fluid discharge ring structure includes a cylinder body, an inlet side connection member having a through hole provided at one end of the cylinder body, a discharge side connection member having a through hole provided at the other end of the cylinder body, and an outer periphery. A spiral blade body having a spiral blade and built in the cylinder body near the inlet side connection member, and a flip-flop phenomenon generating shaft body built in the cylinder body near the discharge side connection member, and the flip-flop The shaft body for the phenomenon of occurrence of a phenomenon is formed with a frustoconical end at one end and a conical end at the other end. It is characterized by being formed with regularity.

4 to 9 are views relating to the fluid discharge pipe structure 101, FIG. 4 is an exploded perspective view of the fluid discharge pipe structure, FIG. 5 is a perspective view of the fluid discharge pipe structure, and FIG. 6 is a fluid discharge pipe structure. FIG. 7 is an explanatory diagram showing a large number of rhombus convex portions having regularity of the flip-flop phenomenon generating shaft, and FIG. 8 is an explanation showing one rhombus convex portion of the flip-flop phenomenon generating shaft. FIG. 9 is an explanatory view of the spiral blade formed in the spiral blade body.

As shown in FIGS. 4 to 6, the fluid discharge pipe structure 101 includes a cylinder body 102, an inlet side connection member 104 having a through hole 103, a discharge side connection member 106 having a through hole 105, and a spiral blade body. 107 and a flip-flop phenomenon generating shaft 108.

More specifically, the cylinder main body 102 (see FIGS. 4 and 6) is a straight cylindrical metal tube formed to have a predetermined diameter and length, and is provided at the inlet side on the inner peripheral surfaces of both ends. The internal thread 109,110 which can attach the connecting member 104 and the discharge side connecting member 106 by screwing together is formed.

In addition, the inlet side connecting member 104 (see FIGS. 4 and 6) having the through hole 103 includes a flange portion 111 formed substantially at the center, a hexagonal nut portion 112 formed on one side of the flange portion 111, It has a cylindrical portion 114 formed on the other side of the flange portion 111 with a male screw 113 that can be screwed to the female screw 109 of the cylindrical main body 102. A tapered portion 115 is formed inside the flange portion 111. The diameter of the through hole 103a on the nut portion 112 side is smaller than the diameter of the through hole 103b of the cylindrical portion 114, and the tapered portion 115 is located between the through hole 103a and the through hole 103b and penetrates from the through hole 103a side. It is formed so as to gradually expand the diameter toward the hole 103b.

On the inner peripheral surface of the cylindrical portion 114, a stepped portion 114a is formed by forming an inner diameter near the tapered portion 115 slightly smaller than other inner diameters. The length from the end 114b of the cylindrical portion 114 to the stepped portion 114a is equal to the entire length of the spiral blade main body 107 described later, and when the spiral blade main body 107 is housed in the cylindrical portion 114, the end 107a of the spiral blade main body 107 is The end 107b of the spiral blade main body 107 is flush with the end 114b of the cylindrical portion 114. When the spiral blade body 107 is housed in the cylindrical portion 114, a space portion 129 is formed between the end 107 a of the spiral blade body 107 and the small diameter end 115 a of the tapered portion 115. The nut portion 112 has an internal thread 116 on the inner peripheral surface so that other pipes can be screwed and connected.

The discharge-side connecting member 106 (see FIGS. 4 and 6) having the through hole 105 includes a flange portion 117 formed near one end, a hexagonal nut portion 118 formed on one side of the flange portion 117, and a flange portion 117. On the other side, a cylindrical portion 120 having a male screw 119 that can be screwed to the female screw 110 of the cylindrical main body 102 is formed. A tapered portion 121 is formed inside the cylindrical portion 120. The diameter of the through hole 105a on the nut part 118 side is smaller than the diameter of the through hole 105b of the cylindrical part 120. The tapered portion 121 is formed in a truncated conical hole shape whose diameter is gradually enlarged from the intermediate portion to the end of the cylindrical portion 120. The nut portion 118 has an internal thread 122 on the inner peripheral surface so that other pipes can be screwed and connected.

The spiral blade main body 107 (see FIGS. 4 and 6) is obtained by processing a short cylindrical member made of a metal having an outer diameter close to the inner peripheral surface of the cylinder main body 102 during storage, and has a circular cross section. It consists of a shaft part 123 and three

spiral blades

124a, 124b, 124c. Each of the

blades

124a, 124b, 124c is positioned by shifting the positions of the

end portions

125a, 125b, 125c by 120 degrees in the circumferential direction of the shaft portion 123. Thus, it is spirally formed counterclockwise.

Each of the

blades

124a, 124b, 124c has a spiral shape as described above at an angle of 75 ° to 76 ° with respect to the horizontal line 126 on the outer periphery of the shaft portion 123 when viewed in plan as shown in FIG. Is formed. The width of the groove, which is the interval between the

blades

124a, 124b, 124c, is 8 mm, the thickness of each

blade

124a, 124b, 124c is 2 mm, and further, from the outer end 127 of each

blade

124a, 124b, 124c to the shaft portion 123. The depth to the outer peripheral surface 128 is 9 mm. Further, both

end portions

125a, 125b, and 125c of the

blades

124a, 124b, and 124c are formed in an acute angle in a blade shape.

The flip-flop phenomenon generating shaft 108 (see FIGS. 4 and 6 to 8) has an outer diameter close to the inner peripheral surface of the cylinder main body 102 when stored, and is about 4/5 of the length of the cylinder main body 102. A metal cylindrical member having a length of 3 mm is processed, and a large number of rhombus convex portions 132 are formed with a predetermined regularity on the outer peripheral surface 131 of the shaft portion 130 having a circular cross section.

That is, the flip-flop phenomenon generating shaft 108 is formed with a frustoconical end portion 134a located on the spiral blade body 107 side when housed in the cylinder body 102, and on the discharge side connecting member 106 side. The other end portion 134b is formed in a conical shape. The other end portion 134b has a top portion 134c formed at 60 °, is positioned in the tapered portion 121 of the discharge-side connecting member 106, and is opposed to the inclined inner surface 121a of the tapered portion 121 with a certain interval. is there.

Further, on the outer peripheral surface 131 of the shaft portion 130 of the shaft body 108 for generating the flip-flop phenomenon, a large number of rhombus convex portions 132 having a predetermined regularity are formed. Each rhombus convex portion 132 is formed so as to protrude outward from the outer peripheral surface 131 by grinding a cylindrical member.

That is, each rhombus convex portion 132 (see FIG. 7) includes a plurality of lines 136 having a constant interval in a direction (circumferential direction) of 90 ° with respect to the longitudinal direction of the cylindrical member, and 60 with respect to the longitudinal direction. Cross the line 137 at regular intervals with an angle of ° (or 62 °), grind between the

lines

136 and 136 one by one, and jump between the

diagonal lines

137 and 137 It is ground every time and formed so as to protrude from the outer peripheral surface 131 of the shaft portion 130 one by one in the vertical direction (circumferential direction) and right and left (longitudinal direction of the shaft portion 130).

By forming each rhombus convex portion 132 in this manner, a large number of rhombus convex portions 132 are arranged with a predetermined regularity on the outer peripheral surface 131 of the shaft portion 130 between both

end portions

134a and 134b. .

As described above, the fluid discharge pipe structure 101 (FIG. 4) configured by the cylinder main body 102, the inlet-side connection member 104, the discharge-side connection member 106, the spiral blade main body 107, and the flip-flop phenomenon generating shaft 108. (See FIG. 6), the discharge-side connecting member 106 is screwed and attached to one end of the cylinder body 102, and the other end 134b of the conical shape of the flip-flop phenomenon generating shaft 108 is inserted into the cylinder body 102 from the other end. Next, the spiral blade main body 107 is inserted, and finally the inlet side connecting member 104 is screwed into one end of the tube main body 102 and attached.

At this time, the tip 133 (see FIG. 6) of one end of the frustoconical shape of the shaft 108 for generating the flip-flop phenomenon comes into contact with one side (one end 107b) of the spiral blade body 107. The spiral blade body 107 is sandwiched between the flip-flop phenomenon generating shaft 108 and the stepped portion 114 a of the inlet side connecting member 104 and is accommodated in the cylinder body 102.

The flow when purified water passes through the fluid discharge pipe structure 101 will be described. The purified water that has flowed from the through-hole 103 of the inlet side connection member 104 (see FIG. 4) hits the flat end 107 a of the spiral blade body 107.

The purified water passes between the

blades

124a, 124b, and 124c formed in the counterclockwise direction of the spiral blade body 107. At this time, the purified water is sent to the frustoconical one end portion 134a of the flip-flop phenomenon generating shaft 108 as a strong tornado flow by the

blades

124a, 124b, 124c. The purified water is then fed between a plurality of rhombus-shaped convex portions 132 having a predetermined regularity formed on the outer peripheral surface 131 of the shaft portion 130 (a plurality of flow paths).

The purified water that passes between the plurality of rhombic convex portions 132 having a regularity (a plurality of flow paths) becomes a turbulent flow and generates innumerable minute vortices (a flip-flop phenomenon is a flow of fluid). It flows toward the other end part 134b of the shaft 108 for generating the flip-flop phenomenon while causing a phenomenon that the direction is periodically changed alternately and flows. The purified water that has flowed into the other end 134b of the conical shape is erased by a tornado flow more than the flip-flop phenomenon due to the size of the gap space with the discharge-side connecting member 106, but the Coanda effect (fluid) When the fluid flows along the wall surface, the phenomenon that the fluid is attracted to the wall surface due to the pressure drop between the fluid and the wall surface is amplified, and the entanglement phenomenon is induced to be discharged from the through-hole 105 of the discharge side connecting member 106. The

The water purifier of the present invention is a large water purifier that can be supplied to a building such as an apartment, an apartment, a building, a hotel, or a plurality of detached houses. The supply amount of purified water of the water purification apparatus of the present invention is appropriately set according to the number of supply destinations and the amount of water used. For example, assuming a case where one water purification device is installed in one apartment building of 100 to 200 units, the supply amount of purified water of the water purification device of the present invention is preferably 3000 L / hour or more, more preferably 4000 L / hour or more. 5000 L / hour or more is more preferable, 8000 L / hour or less is preferable, 7000 L / hour or less is more preferable, and 6000 L / hour or less is more preferable.

(2) Manufacturing method of the purified water of this invention Next, the manufacturing method of the purified water of this invention is demonstrated. In the water purification method of the present invention, during normal filtration operation, raw water is supplied in parallel to a plurality of membrane modules having at least a first membrane module and a second membrane module, and the raw water is filtered through the plurality of membrane modules. At the time of reverse cleaning operation, the raw water is supplied to one of the first membrane module or the second membrane module while pulsating the water pressure of the raw water and filtered, and at least a part of the obtained purified water is reversed. As washing water, the other membrane module is backwashed from the downstream side to the upstream side of the other membrane module, and the other membrane module is backwashed.

In a more preferred embodiment of the production method of the present invention, at the time of backwashing operation, raw water is supplied to the first membrane module while pulsating the water pressure of the raw water and filtered, and at least a part of the obtained purified water is backwashed. Back flow from the downstream side of the second membrane module to the upstream side, back washing the second membrane module, and further, supplying raw water to the second membrane module while pulsating the water pressure of the raw water and filtering, At least a part of the purified water thus obtained is backwashed from the downstream side of the first membrane module to the upstream side, and the first membrane module is backwashed.

First, the normal filtration operation process will be described with reference to the drawings. FIG. 10 is a diagram showing a water flow state of the purification device 1 of the present invention during normal filtration operation. As shown in FIG. 10, during the normal filtration operation, the first to third valves V1 to V3 and the eighth valve V8 are released, and the fourth to fifth valves V4 to V5 and the ninth valve V9 are closed. Thus, a raw water treatment line is formed in which the raw water supply path 3, the raw

water branch paths

5A and 5B, the purified

water branch paths

11A and 11B, and the purified water path 13 communicate with each other through the

membrane modules

9A and 9B. The valve opening / closing operation may be automatic control by the valve control unit or may be manually controlled.

The raw water supply means P1 pressurizes the raw water and sends it to the raw water supply path. The pressure of the raw water is preferably set as appropriate according to the allowable pressure of the membrane module to be used. For example, in the case of an ultrafiltration membrane (UF membrane) and a microfiltration membrane (MF membrane), the allowable pressure is about 0.35 MPa, and the pressure Pf of the pressurized raw water is preferably 0.2 MPa or more, 0.25 MPa or more is more preferable, 0.28 MPa or more is more preferable, 0.35 MPa or less is preferable, 0.32 MPa or less is more preferable, and 0.30 MPa or less is more preferable. When the pressure Pf of the pressurized raw water exceeds the allowable pressure, the filtration membrane is easily damaged. Moreover, if the pressure Pf of the pressurized raw water is too low, the flow rate of the raw water is reduced. Note that, unlike the reverse cleaning operation, the pressure Pf of the raw water is preferably substantially constant during the normal filtration operation.

The raw water branches at the branch point 4 and is supplied to the first and

second membrane modules

9A and 9B through the raw

water branch paths

5A and 5B. The raw water is filtered by the first and

second membrane modules

9A and 9B. Foreign matter and turbidity contained in the raw water are removed by the membrane module. When the raw water is filtered by the first and

second membrane modules

9A and 9B, the fourth and fifth valves V4 and V5 are opened, and the concentrated water is filtered while being discharged from the

discharge passages

7A and 7B. A method may be adopted. Moreover, you may employ | adopt the dead end system which closes the 4th and 5th valve | bulb V4, V5, and filters raw | natural water. When the dead end method is adopted, foreign matter accumulates in the reservoirs in the

membrane modules

9A and 9B, so the fourth and fifth valves V4 and V5 are occasionally released to discharge the foreign matter. It is preferable to do.

The purified water discharged from the first and

second membrane modules

9A and 9B merges at the junction 17 through the purified

water branch paths

11A and 11B, and flows out to the purified water path 13, respectively.

Chemicals may be added to the purified water as necessary. As shown in FIG. 3, the chemical liquid is supplied from the chemical liquid tank 41 to the purified water flowing through the water purification path 13 via the pump P2. Although it does not specifically limit as said chemical | medical solution, For example, hypochlorous acid, sodium hypochlorite, hypochlorous acid aqueous solution, etc. can be mentioned. Among these, it is preferable to use a sodium hypochlorite aqueous solution. By adding sodium hypochlorite, it ionizes to hypochlorite ions in water, and part of it reacts with water to form hypochlorous acid. In the purified water discharged from the water purifier by these sterilizing powers, for example, it is possible to prevent the growth of bacteria in the piping from the water purifier of the present invention to each use location, and the purified water until the user uses it for drinking etc. Safety can be maintained.

When sodium hypochlorite is added to purified water, the chlorine concentration in the obtained purified water is preferably 0.3 mg / L or more in consideration of the relationship between sterilizing power and chlorine removal efficiency in the secondary water purification device. 0.4 mg / L or more is more preferable, 0.5 mg / L or more is more preferable, 0.8 mg / L or less is preferable, and 0.7 mg / L or less is more preferable. By containing chlorine in the purified water in this way, even when the raw water is tap water containing chlorine, even if the chlorine is removed in the process of removing impurities in the water purification device of the present invention, the purified water flowing out from the device Chlorine can be contained, and even when water containing no chlorine is used as raw water, chlorine can be added, and the sanitation is excellent.

It is also preferable to add a nucleating agent, a flocculant or a pH adjuster to the raw water and then filter with a membrane module. By adding a nucleating agent, a flocculant, or a pH adjuster to the raw water, impurities such as charged metal ions, arsenic, fluorine, silica, and chlorine contained in the raw water can be agglomerated. The obtained agglomerates have a large particle size and are easily removed by precipitation or filtration. When a nucleating agent is used, there is an effect of binding at an ion level, and minute metal ions in water can be aggregated with little remaining. On the other hand, when an aggregating agent is used, when impurities are included in high turbidity, there is an advantage that impurities can be efficiently aggregated and removed in large quantities, but minute metal ions cannot be completely removed. Therefore, a nucleating agent should be used when heavy metals such as arsenic, lead, and iron are present as ions in water, and a flocculant should be used when removing large amounts of impurities in water. . As the nucleating agent, for example, a ferric hydroxide colloid solution can be used. As the pH adjuster, sodium hydroxide or the like can be used when adjusting from the acid side to the alkali side, and dilute hydrochloric acid or carbonic acid can be used when adjusting from the alkali side to the acid side. As the flocculant, for example, polyaluminum chloride generally called PAC and aluminum sulfate generally called sulfate band can be used. For example, a chemical solution such as a nucleating agent or a flocculant may be added from the chemical solution tank 37 to the raw water tank 35 provided on the upstream side of the raw water supply path 3 via the pump P3 as shown in FIG. However, it may be added directly to the raw water flowing in the raw water supply path 3.

Next, the reverse cleaning operation process will be described with reference to the drawings. At the time of backwashing operation, the raw water is supplied to one of the first membrane module or the second membrane module while pulsating the raw water pressure and filtered, and at least a part of the obtained purified water is used as the backwash water. The other membrane module is backwashed by flowing backward from the downstream side of the membrane module to the upstream side.

Hereinafter, the case where the first membrane module is operated in the filtered state and the second membrane module is back-washed will be specifically described with reference to FIG. In order to place the first membrane module in the filtration state and the second membrane module in the backwash state, the first and second valves V1, V2, the fifth valve V5, and the eighth valve V8 are released, and the third, fourth, The valves V3 and V4 and the ninth valve V9 are closed. The valve opening / closing operation may be automatic control by the valve control unit or may be manually controlled. By this valve operation, a raw water treatment line is formed in which the raw water supply path 3, the raw water branch path 5A, the purified water branch path 11A, and the purified water path 13 communicate with each other through the membrane module 9A. Further, a backwash line is formed in which the purified water branch path 11B and the discharge path 7B communicate with each other via the second membrane module 9B.

At least a part of the purified water discharged from the first membrane module 9A flows back through the purified water branch 11B as backwash water, and passes from the purified water discharge port 9h downstream of the second membrane module 9B to the second membrane module 9B. invade. The backwash water that has entered the second membrane module 9B passes through the membrane means 9c disposed in the second membrane module 9B, and flows out from the upstream concentrated water discharge port 9i to the discharge path 7B. At this time, the foreign matter adhering to the membrane means 9c of the second membrane module 9B is released and flows out into the discharge path 7B together with the backwash water. The foreign matter adhering to the backwash water and the second membrane module 9B is discharged out of the water purifier from the discharge path 7B connected to the concentrated water discharge port 9i.

Further, the remaining portion of the purified water discharged from the first membrane module 9A flows out to the purified water channel 13. Thereby, it is possible to continue discharging a certain amount of purified water while backwashing the second membrane module 9B. Note that the eighth valve V8 may be closed and all the purified water discharged from the first membrane module 9A may be backwashed water.

In the above, as the backwash line, a line in which the purified water branch path 11B, the second membrane module 9B, and the discharge path 7B communicate with each other is adopted. For example, as shown in FIG. 2, the purified water branch path 11B, A line in which the raw water branch 5B and the discharge path 15B communicate with each other via the second membrane module 9B may be adopted.

During the reverse cleaning operation, the raw water supply means P1 supplies raw water to the first membrane module 9A while pulsating the water pressure of the raw water. Supplying the raw water to the first membrane module 9A while pulsating the water pressure of the raw water pulsates the purified water discharged from the first membrane module 9A, that is, the backwash water pressure, so that the reverse of the second membrane module 9B This is because the cleaning efficiency is increased. As a method of pulsating the water pressure of the raw water, for example, it is preferable to continuously change the rotation speed of the raw material supply means P1 by the inverter control unit 23.

FIG. 12 is a graph schematically showing changes in pressure of raw water during normal filtration operation and backwash operation. The area of T0 represents the pressure Pf of the raw water during the normal filtration operation, and the area of T1 represents the pressure change of the raw water during the reverse cleaning operation. As is apparent from FIG. 12, it is preferable that the pressure Pf of the raw water is substantially constant during the normal filtration operation, and the pressure of the raw water is pulsated during the back washing operation. When the normal filtration operation and the reverse cleaning operation are alternately switched by a timer and the membrane module is periodically back cleaned, the normal filtration operation time T0 is preferably as long as possible. For example, the quality of raw water Or, it may be set appropriately according to the raw water treatment amount. Therefore, the normal filtration operation time T0 may vary within a range of several minutes, several hours to several days. On the other hand, the time T1 during the reverse cleaning operation is preferably as short as possible from the viewpoint of increasing the water purification efficiency. The time T1 during the reverse cleaning operation is preferably 0.5 minutes to 20 minutes, more preferably 1 minute to 10 minutes, and further preferably about 5 minutes to 7 minutes.

It is preferable to pulsate the pressure of the raw water during the reverse cleaning operation. The pulsation of the pressure of the raw water means that the pressure of the raw water changes periodically or aperiodically. More preferably, the pressure of the raw water during the reverse cleaning operation is periodically changed between a high pressure and a low pressure, and more preferably continuously changed between the high pressure and the low pressure.

As the pressure of the raw water during the reverse cleaning operation, for example, a mode in which the pressure is changed so as to draw a sine curve as shown in FIG. By continuously changing between the high pressure and the low pressure, it is possible to reduce the burden of pressure increase / decrease on the filtration membrane. FIG. 12A shows a mode in which the pressure of the raw water during the reverse cleaning operation is changed so as to draw a sine curve. For example, as shown in FIG. Then, the magnitude of the pressure change may be changed so as to attenuate. This is because it is considered that the influence of the first pressure increase / decrease is large in the removal of foreign matters during reverse cleaning.

Further, the pressure of the raw water during the reverse cleaning operation is periodically increased as shown in FIG. 12C, for example, by linearly increasing and decreasing between the maximum pressure value Pmax and the minimum pressure value Pmin. You may make it change to low pressure. Further, as shown in FIG. 12D, after the pressure is linearly decreased from the maximum pressure value Pmax to the minimum pressure value Pmin, the minimum pressure value Pmin is maintained for a predetermined time, and the minimum pressure value Pmin is changed to the maximum pressure value. The pressure may be linearly increased to the value Pmax, the maximum pressure value Pmax may be maintained for a predetermined time, and periodically changed between high pressure and low pressure.

When pulsating the pressure of the raw water during the reverse cleaning operation, the ratio (Pmax / Pmix) of the maximum pressure value Pmax to the minimum pressure value Pmin is preferably 1.3 or more, more preferably 1.5 or more, and 2.5 or less. Is preferably 2.3 or less, more preferably 2.0 or less. If the value of the ratio (Pmax / Pmix) is greater than or equal to the lower limit, the pressure difference becomes large and the reverse cleaning ability increases. Moreover, if the value of the ratio (Pmax / Pmix) is less than or equal to the upper limit, the filtration membrane is less likely to be damaged due to the pressure difference of the raw water.

Further, the maximum pressure value Pmax may be appropriately set according to the permissible pressure of the filtration membrane provided in the membrane module. For example, when an ultrafiltration membrane or a microfiltration membrane is used as the filtration membrane, the maximum pressure value Pmax is preferably 0.15 MPa or more, more preferably 0.17 MPa or more, particularly preferably 0.18 MPa or more, and 0.25 MPa. The following is preferable, 0.20 MPa or less is more preferable, and 0.19 MPa or less is particularly preferable. If the maximum pressure value Pmax becomes too large, the filtration membrane of the membrane module may be damaged. In addition, if the maximum pressure value Pmax is too small, the difference between the maximum pressure value Pmax and the minimum pressure value Pmin becomes small, which may reduce the back cleaning effect.

For example, when an ultrafiltration membrane or a microfiltration membrane is used as the filtration membrane, the minimum pressure value Pmin is preferably 0.10 MPa or more, more preferably 0.12 MPa or more, particularly preferably 0.13 MPa or more, and 0.20 MPa. The following is preferable, 0.15 MPa or less is more preferable, and 0.14 MPa or less is particularly preferable. If the minimum pressure value Pmin becomes too large, the difference between the maximum pressure value Pmax and the minimum pressure value Pmin becomes small, and the back cleaning effect may be reduced. If the minimum pressure value Pmin is too small, the back cleaning effect may be reduced due to the resistance of the film.

The frequency (f) for periodically changing the water pressure of the raw water is, for example, preferably 5 cycles / minute or more, more preferably 7 cycles / minute or more, further preferably 10 cycles / minute or more, and 20 cycles / minute or less. Preferably, 15 cycles / min or less is more preferable, and 12 cycles / min or less is more preferable. If the frequency becomes too high, the pressure increases and decreases sharply, and the membrane of the membrane module may be damaged. In addition, if the frequency is too small, the increase or decrease in pressure is too small, and the back cleaning effect may be reduced.

Also, the reciprocal of the frequency (f) (cycles / minute) means a period (T) (minutes) in which one cycle is performed. In the present invention, the value [(Pmax / Pmin) · T] (unit: minute) obtained by multiplying the ratio (Pmax / Pmin) of the maximum pressure value Pmax to the minimum pressure value Pmin by the period (T) (minutes) is 3 or more. Is preferable, 5 or more is more preferable, 7 or more is more preferable, 20 or less is preferable, 15 or less is more preferable, and 10 or less is more preferable. If the value of [(Pmax / Pmin) · T] becomes too large, the degree of pressure change becomes abrupt and the filtration membrane is easily damaged. Moreover, if the value of [(Pmax / Pmin) · T] becomes too small, the back cleaning effect may be insufficient.

Next, the case where the second membrane module 9B is operated in the filtered state and the first membrane module 9A is backwashed will be described with reference to FIG. In order to operate the second membrane module 9B in the filtration state and put the first membrane module 9A in the backwash state, the first, third valves V1, V3, the fourth valve V4, and the eighth valve V8 are released, The same operation may be performed by closing the second valve V2, the fifth valve V5, and the ninth valve V9. The valve opening / closing operation may be automatic control by the valve control unit or may be manually controlled. By this valve operation, a raw water treatment line is formed in which the raw water supply path 3, the raw water branch path 5B, the purified water branch path 11B, and the purified water path 13 communicate with each other through the second membrane module 9B. Moreover, the purified water branch path 11A and the discharge path 7A form a backwash line communicating with the first membrane module 9A.

In the above, as the backwash line, the purified water branch path 11A and the discharge path 7A adopted the backwash line communicated via the first membrane module 9A. For example, as shown in FIG. As the backwash line, a line in which the purified water branch path 11A, the raw water branch path 5A, and the discharge path 15A communicate with each other via the first membrane module 9A may be adopted.

In the method for producing purified water according to the present invention, it is preferable to perform the operations of the following (1) to (3) while switching appropriately.
(1) Normal filtration operation in which raw water is filtered by both the first membrane module and the second membrane module (2) Back washing operation in which the first membrane module is put into the filtration state and the second membrane module is put in the back washing state (3) Backwash operation in which the second membrane module is in the filtration state and the first membrane module is in the backwash state The operation is switched, for example, by manual switch operation data, differential pressure data supplied by the membrane differential pressure calculator, or a timer It is preferable to carry out based on time data or the like.

The operation time T0 of the normal filtration operation may be appropriately set according to the quality of raw water, the treatment speed, and the like. Therefore, the normal filtration operation time T0 may vary within a range of several minutes, several hours to several days. The time T1a of the back washing operation in which the first membrane module 9A is filtered and the second membrane module 9B is back washed is preferably 30 seconds or more, more preferably 1 minute or more, particularly preferably 5 minutes or more, 20 Minutes or less is preferable, 10 minutes or less is more preferable, and 7 minutes or less is particularly preferable. The time T1b of the back washing operation in which the second membrane module 9B is in the filtration state and the first membrane module 9A is in the back washing state is preferably 30 seconds or more, more preferably 1 minute or more, particularly preferably 5 minutes or more, 20 Minutes or less is preferable, 10 minutes or less is more preferable, and 7 minutes or less is particularly preferable.

In the method for producing purified water of the present invention, it is also preferable to mix microbubbles in the backwash water for washing the membrane module. The microbubbles mixed in the backwash water give vibration to the filtration membrane when passing through the filtration membrane. As a result, foreign matter adhering to the filtration membrane is released, and the back cleaning efficiency is increased. A microbubble is a fine bubble having a diameter of 10 μm to several tens of micrometers or less when it is generated. The reason for the occurrence is that the microbubbles may contract and change into micro-nano bubbles. Micro-nano bubbles are fine bubbles having a diameter of several hundred nanometers to less than 10 μm.

In order to enhance the reverse cleaning effect, the volume average particle diameter of microbubbles (including micronanobubbles) is preferably 500 μm or less, more preferably 100 μm or less, and even more preferably 10 μm or less. The lower limit of the volume average particle diameter of microbubbles (including micronanobubbles) is not particularly limited, but is preferably 1 nm, more preferably 10 nm, and even more preferably 100 nm. When the volume average particle diameter of microbubbles (including micronanobubbles) becomes too small, the generation cost increases and the backwashing effect tends to be saturated. Further, the proportion of microbubbles (including micro-nano bubbles) having a particle diameter of 500 μm or less and 1 nm or more in all bubbles is preferably 50% by volume or more, more preferably 70% by volume or more, and still more preferably 90% by volume or more. In addition, the particle diameter and volume average particle diameter of microbubbles (including micro-nano bubbles) are the particle diameter and volume average particle diameter at the outlet of the microbubble generator.

The ratio (V1 / V2) of the total volume V1 of the generated microbubbles (including micro-nanobubbles) to the volume V2 of the backwash liquid mixed with the microbubbles is not particularly limited, but is preferably 0.01 or more, and 05 or more is more preferable, 0.1 or more is more preferable, 0.5 or less is preferable, 0.3 or less is more preferable, and 0.2 or less is more preferable. When the ratio is too small, the effect of increasing the back cleaning efficiency is reduced. If the ratio is too large, the proportion of backwash water may be too small, and the backwash efficiency may decrease. In addition, the cost of generating microbubbles increases.

[Water purification equipment]
14 to 20 show a water purifier according to an embodiment of the present invention. FIG. 14 is a front view of a water purifier according to an embodiment of the present invention. 15 is a right side view of FIG. 14, FIG. 16 is a left side view of FIG. 14, FIG. 17 is a rear view of FIG. 14, and FIG. 18 is a plan view of FIG. FIG. 19 is a bottom view of FIG. FIG. 20 shows a flow chart of the water purifier of FIGS. In addition, the water purifier of this invention is not limited to the form illustrated in the said drawing.

The water purifier 1 is disposed in the raw water supply path 3, the raw water supply path 3, and the raw water supply means P1 that feeds the raw water, and a plurality of raw

water branch paths

5A and 5B that branch the raw water supply path 3 into at least two or more. And a plurality of

membrane modules

9A, 9B disposed in the plurality of raw

water branch paths

5A, 5B and purifying the raw water, and

discharge paths

7A, 7B connected to the upstream side of the membrane means for purifying the raw water included in the membrane module. And a plurality of

water purification branches

11A and 11B connected to the downstream side of the plurality of membrane modules, and a water purification path 13 where the plurality of

water purification branches

11A and 11B merge.

As shown in FIG. 14 to FIG. 19, each component constituting the water purifier 1 is housed in a gantry having a width of 1400 mm × a depth of 1000 mm × a height of 1985 mm and is unitized.

As shown in FIG. 16, the raw water supply port 40 is disposed below the left side surface on the back side of the water purifier 1. The raw water supply port 40 may be directly coupled to the water main or may be connected to a raw water tank that stores tap water from the water main. The raw water is fed by a pump as raw water supply means P1. As shown in FIG. 17, the raw water supply path 3 is disposed so as to be inclined obliquely upward from the discharge port of the raw water supply means P 1 and bend from the back side to the front side at a predetermined height. At the predetermined height, the raw water supply path 3 from the back side to the front side is provided with a check valve for preventing a backflow of backwash water. Moreover, as shown in FIG.14 and FIG.19, the raw | natural water supply path 3 is arrange | positioned so that it may go down on the front side of the water purifier 1, and may bend from the front side to the back side in the bottom part. As shown in FIG. 19, raw water branch paths 5 A and 5 B are connected to a portion of the raw water supply path 3 from the front side to the back side. The raw

water supply paths

5A and 5B are each provided with inflow valves (air valves) V2 and V3 for opening and closing the flow paths.

As shown in FIGS. 14 to 15, the water purifier 1 has two membrane modules 9A and two membrane modules 9B connected to the raw

water supply paths

5A and 5B, respectively. The

membrane modules

9A and 9B have a substantially cylindrical shape. The

membrane modules

9A and 9B are connected to the

raw water branch

5A and 5B at the raw water inlet 9g, connected to the

outlets

7A and 7B at the concentrated water outlet 9i, and the purified

water branch

11A and 11B at the purified water outlet 9h. Connected to. During normal filtration operation, raw water can be supplied to both the two membrane modules 9A and the two membrane modules 9B for filtration. As shown in FIG. 17, the purified water purified by the

membrane modules

9A and 9B is discharged to the purified

water branch paths

11A and 11B connected to the downstream side of the

membrane modules

9A and 9B. As shown in FIGS. 16 and 17, the purified water branch paths 11 A and 11 B merge at a junction 17 to form a purified water path 13. The purified water is discharged from the purified water discharge port 42 disposed on the upper side of the left side surface.

During the reverse cleaning operation, raw water is supplied to one of the two membrane modules 9A or two membrane modules 9B and filtered, and the obtained purified water is supplied to the other membrane module as backwash water. The backwash water is discharged from the

discharge paths

7A and 7B. The

discharge paths

7A and 7B are respectively connected to the raw water regions of the

membrane modules

9A and 9B, and are provided with inflow valves (air valves) V4 and V5 for opening and closing the flow paths. As shown in FIGS. 16 and 17, the discharge path 7A and the discharge path 7B merge and are connected to the discharge path 7C. The backwash water is discharged from a discharge port 48 that is an end of the discharge path 7C.

As an inflow valve used for opening and closing the flow path, an air valve whose opening and closing is controlled by compressed air from the compressor C is used. The control unit 21 includes an air valve control unit having a solenoid valve, and controls opening and closing of each air valve.

As shown in FIG. 19, the downstream end of the raw water supply passage 3 is connected to the drainage passage 44 via the tenth valve V10. The drainage channel 44 is for draining water in the membrane module when the membrane means of the membrane module is replaced. The drainage channel 44 merges with the discharge channel 7C. By opening the second, third, and tenth valves V2, V3, and V10, the water in the membrane module can be drained from the discharge port 48.

The water purifier 1 may include a chemical tank 46 for adding a chemical to raw water or purified water. As a chemical | medical agent of the chemical | medical solution tank 46, the flocculant added to raw | natural water, a pH adjuster, etc. are preferable.

The water purifier of the present invention is small and has high backwashing efficiency. The water purifier of the present invention is suitable as a water purifier that supplies purified water to the entire building such as an apartment or a building.

1: Water purification device, 3: Raw water supply path, 5A, 5B: Raw water branch path, 7A, 7B: Discharge path, 9A, 9B: Membrane module, 11A, 11B: Purified water branch path, 13: Clean water path, P1: Raw water supply Means 18: Pressure gauge

Claims

Raw water supply channel,
Raw water supply means that is disposed in the raw water supply path and feeds raw water,
A plurality of raw water branch paths that branch the raw water supply path into at least two or more;
A plurality of membrane modules arranged in the plurality of raw water branch paths to purify the raw water;
A discharge path connected to the upstream side of the membrane means for purifying raw water included in the plurality of membrane modules;
A plurality of water purification branches connected to the downstream side of the plurality of membrane modules;
A water purification apparatus comprising: a water purification path where the plurality of water purification branch paths merge.
The water purifier according to claim 1, wherein the discharge path is provided with a discharge valve for opening and closing the discharge path, and the raw water branch path is provided with an inflow valve for opening and closing the flow path of the raw water branch path.
The membrane module includes a raw water region to which raw water is supplied, a membrane means for purifying the raw water, a purified water region from which purified water purified by the membrane means flows out, and the discharge path is connected to the raw water region. The water purifier of Claim 1 or 2.
The water purifier according to claim 1 or 2, wherein the discharge path is connected to a raw water branch path downstream of an inflow valve that opens and closes the flow path of the raw water branch path.
The water purifier according to any one of claims 1 to 4, further comprising an inverter control unit that controls the raw water supply means so as to pulsate the water pressure of the raw water.
The water purifier according to any one of claims 1 to 5, wherein a flow path including microbubble generating means is formed in parallel in the water purification branch.
The water purifier according to any one of claims 1 to 6, wherein the membrane module comprises a microfiltration membrane or an ultrafiltration membrane as membrane means.
The water purifier according to any one of claims 1 to 7, comprising a raw water tank and means for supplying a chemical solution to the raw water tank.
During normal filtration operation, raw water is supplied in parallel to a plurality of membrane modules having at least a first membrane module and a second membrane module, and purified water is produced by filtering the raw water through the plurality of membrane modules.
At the time of backwashing operation, the raw water is supplied to one of the first membrane module or the second membrane module while pulsating the raw water pressure and filtered, and at least a part of the obtained purified water is used as the backwash water. A method for producing purified water, characterized in that a reverse flow is performed from the downstream side of the membrane module to the upstream side, and the other membrane module is backwashed.
At the time of backwashing operation, raw water is supplied to the first membrane module while pulsating the water pressure of the raw water and filtered, and at least a part of the obtained purified water is used as backwash water from the downstream side of the second membrane module. Back flow to the side, back washing the second membrane module, supplying raw water to the second membrane module while pulsating the water pressure of raw water, filtering, and backwashing at least a part of the purified water obtained The method for producing purified water according to claim 9, wherein the first membrane module is backwashed as water by flowing backward from the downstream side of the first membrane module to the upstream side.
10. The raw water is pulsated so that a ratio (Pmax / Pmix) of the maximum pressure value Pmax to the minimum pressure value Pmin of the water pressure of the raw water is 1.3 or more and 2.5 or less during the reverse cleaning operation. 10. The method for producing purified water according to 10.
The method for producing purified water according to any one of claims 9 to 11, wherein purified water is produced using the water purification device according to any one of claims 1 to 8.