WO2011099578A1

WO2011099578A1 - Water purification device

Info

Publication number: WO2011099578A1
Application number: PCT/JP2011/052929
Authority: WO
Inventors: 邦彦山中; 精一石川
Original assignee: Yamanaka Kunihiko; Ishikawa Seiichi
Priority date: 2010-02-13
Filing date: 2011-02-10
Publication date: 2011-08-18
Also published as: JPWO2011099578A1; JP5563604B2

Abstract

Disclosed is a water purification device having excellent versatility, which is capable of reliably and efficiently eliminating impurities, bacteria, or the like adhered to a filtration membrane to suppress bacterial growth with a simple configuration without using a chemical solution, has excellent washing efficiency and environmental protection performance of the filtration membrane, improves the durability, long life performance, and maintenance performance of the filtration membrane significantly, prevents the time degradation of filtration performance, has excellent stability of operation, efficiency of filtration, and energy conservation performance, is capable of controlling an electrolyte component, or the like in filtrate to easily adjust the purity of the filtrate, and is capable of using the filtrate for a wide range of applications such as drinking water, or washing water for food, tableware, or the like. Specifically disclosed is a water purification device which is provided with: a raw water tank; a raw water supply line that supplies raw water to a filtration section; a concentrated water circulation line that allows the circulation of concentrated water; a filtrate discharge line that discharges filtrate; a filtrate tank that stores the filtrate; a concentrated water discharge line that discharges the concentrated water to the raw water tank; a raw-water-side bubble generating section that bubbles the interior of the raw water tank; and a washing filtrate supply line that supplies the filtrate as washing water.

Description

Water purifier

The present invention relates to a circulation type water purifier that performs partial filtration with a filtration membrane, can suppress the growth of bacteria, eliminates the need for cleaning with a chemical solution, or can greatly reduce the frequency thereof, maintainability, environmental conservation It is related with the water purifier excellent in property and energy saving.

Conventionally, membrane separation technology has been used in a wide range of fields such as desalination of seawater and brine, medical and industrial pure water, ultrapure water production, industrial wastewater treatment, and food industry.
For example, (Patent Document 1) includes a desalination apparatus for seawater (or brine), (Patent Document 2) includes a system for producing a sterile aqueous solution, and (Patent Document 3) includes a water treatment apparatus for processing sewage such as sewage. It is disclosed.
In recent years, water shortages are becoming a serious problem on a global scale, and there is a growing demand for technologies for recycling organic wastewater including industrial wastewater and domestic wastewater.
Of particular note is the use of membrane filtration methods such as reverse osmosis membranes and ultrafiltration membranes to produce reclaimed water with extremely good water quality that can be used as industrial, agricultural, or household water. Yes.

JP-A-6-23356 JP 7-8996 A Japanese Patent Application Laid-Open No. 2007-244979

However, the above conventional techniques have the following problems.
(1) In filtration using a reverse osmosis membrane or ultrafiltration membrane, components such as inorganic ions and organic substances dissolved in the solution (raw water) can be separated and removed, but concentrated or precipitated colloids, hardly soluble Produced when impurities such as basic salts and bacteria adhere to or propagate on the surface of reverse osmosis membranes (ultrafiltration membranes), clogging the filtration membranes, and the filtration (water permeability) performance deteriorates over time There was a problem that the purity (water quality) of the filtrate was likely to be lowered, and the long-life property of the filtration membrane and the water quality stability of the filtrate were lacking.
(2) Also, if the filtration performance deteriorates due to clogging, after washing the filtration membrane by circulating an alkaline or acidic cleaning agent through the chemical solution circulation line, the chemical solution remaining on the filtration membrane is washed away with a large amount of water. There is a problem in that it requires complicated work and lacks maintainability, resource saving, and environmental conservation.
(3) Furthermore, even if the water permeability of the filtration membrane is restored by chemical cleaning, the filtration membrane itself may be chemically deteriorated and the water quality may not be restored. In that case, the filtration membrane must be replaced. There was a problem of lack of resource saving and durability.
(4) In the production of reverse osmosis water (ultrafiltration water) using a reverse osmosis membrane (ultrafiltration membrane), the pressurization pump is intermittently operated, but this intermittent operation places a burden on the pressurization pump. In addition, the reverse osmosis membrane (ultrafiltration membrane) is also subjected to pulsation load, the physical burden on the filtration membrane is large, the amount of membrane adhering due to concentration of raw water also increases, the long life of the device and filtration membrane, There was a problem of lack of durability and operational stability.
(5) The dissolved oxygen concentration of filtrated water by membrane filtration is likely to fluctuate under the influence of the raw water-soluble oxygen concentration, and there is a problem that the quality (dissolved oxygen concentration) is not stable.

The present invention solves the above-mentioned conventional problems, with a simple configuration, without using a chemical solution, or significantly reducing the frequency, and reliably and efficiently removing solid particles and bacteria attached to the filtration membrane. Bacteria growth can be suppressed, filtration membrane cleaning efficiency and environmental protection are excellent, and the durability, long life and maintenance of the filtration membrane can be greatly improved. Prevention, stability of operation, filtration efficiency, energy saving, and control of electrolyte components contained in filtered water, which can easily adjust the conductivity and dissolved oxygen concentration of filtered water. The purpose is to provide a water purifier with excellent versatility that can be used for a wide range of purposes such as drinking water, washing water for foods, tableware and the like.

In order to solve the above problems, the water purifier of the present invention has the following configuration.
The water purification apparatus according to claim 1 of the present invention is a circulation type water purification apparatus that performs partial filtration with a filtration membrane disposed in a filtration unit, the raw water tank storing raw water, the raw water tank, and the A raw water supply line having a raw water supply pump and a raw water supply valve for connecting the filtration unit and supplying the raw water from the raw water tank to the filtration unit, and an upstream side of the raw water supply pump and the filtration unit connected to the raw water supply line A concentrated water circulation line that circulates the concentrated water in which the solid particles are concentrated in the filtration unit, and a filtered water discharge line that has a filtered water discharge valve that is connected to the filtration unit and discharges the filtered water filtered by the filtration unit; A concentrated water drain having a filtrate water tank for storing filtrate discharged from the filtrate drain line, and a concentrated water discharge valve for branching from the concentrate circulation line and discharging the concentrated water to the raw water tank. A raw water-side bubble generating part that is disposed downstream of the concentrated water discharge valve of the concentrated water discharge line and bubbles in the raw water tank, and from the upstream side of the filtered water discharge valve of the filtered water discharge line A filtered filtrate supply line for washing having a filtrate supply valve that branches and is connected to the concentrated water circulation line downstream from the branch position of the concentrated water circulation line with the concentrated water discharge line and supplies the filtrate as washing water. And a configuration provided with.
This configuration has the following effects.
(1) A raw water tank in which raw water is stored, a raw water supply line having a raw water supply pump and a raw water supply valve that connect the raw water tank and the filtration unit and supply raw water from the raw water tank to the filtration unit, and a raw water supply of the raw water supply line Concentrated between the raw water supply line and the filtration unit by continuously operating the raw water supply pump because it has a concentrated water circulation line that connects the upstream side of the pump and the filtration unit and circulates the concentrated water in which the solid particles are concentrated in the filtration unit. Filtration can be performed while circulating water, the load of the raw water supply pump can be reduced, and the durability and operational stability are excellent.
(2) A concentrated water discharge line having a concentrated water discharge valve that branches off from the concentrated water circulation line and discharges the concentrated water to the raw water tank is provided. Therefore, the concentrated water can be prevented from being excessively concentrated, clogging of the filtration membrane can be reduced, and the filtration efficiency is excellent.
(3) Oxidizing organic substances or iron, magnesium, manganese, calcium, etc., by depositing a raw water side bubble generating part that is arranged downstream from the concentrated water discharge valve of the concentrated water discharge line and bubbles inside the raw water tank Therefore, the supernatant liquid in the raw water tank can be supplied to the filtration unit and efficiently filtered in a short time, and the filtration efficiency is excellent.
(4) Branch from the filtrate drain valve upstream from the filtrate drain valve and connect to the concentrate circulation line downstream from the branch position with the concentrate drain line of the concentrate circulation line to supply filtrate as wash water By providing a washing filtrate supply line with a filtration water supply valve, the raw water side of the filtration membrane can be washed with filtered water, which eliminates the need for chemical cleaning or greatly reduces the frequency of the environment. Excellent protection, the filtration membrane does not deteriorate chemically, and the filtration membrane has excellent durability and long life.

Here, as a filtration membrane, an ultrafiltration membrane, a reverse osmosis membrane, a hollow fiber membrane, etc. can be used.
The raw water supply pump is not limited as long as it can suck the raw water from the raw water tank and supply it to the filtration unit and circulate the concentrated water concentrated in the filtration unit, but a centrifugal pump or the like is preferably used. .
As the raw water supply valve, the filtrate discharge valve, and the filtrate supply valve, electromagnetic valves are preferably used.
The raw water side bubble generating unit may be any unit that can generate bubbles, but sucks ambient air into the drainage pipe using the negative pressure generated when the concentrated water is discharged from the concentrated water discharge line. Those that generate bubbles are preferably used. This is because drainage energy can be used effectively, no special power is required, and energy saving is excellent.

Invention of Claim 2 is a water purifier of Claim 1, Comprising: The switching valve arrange | positioned downstream from the said filtrate water supply valve of the said filtration water supply line for washing | cleaning, and the said filtrate water supply A drainage line that branches from the cleaning filtrate supply line between the valve and the switching valve and is connected to the raw water tank.
With this configuration, in addition to the operation of the first aspect, the following operation is provided.
(1) A switching valve disposed downstream from the filtrate water supply valve of the filtrate water supply line for washing and a branch from the filtrate water supply line for washing between the filtrate water supply valve and the selector valve are connected to the raw water tank. Since the drainage line is used, the filtration water supply valve of the washing filtrate supply line is closed during filtration, and the switching valve is opened, so that a part of the washing filtrate supply line is used to remove the raw water tank from the drainage line. Concentrated water can be discharged, the piping can be simplified and the apparatus can be miniaturized, and space saving and mass productivity are excellent.
(2) Since the drainage line is arranged in parallel with the concentrated water discharge line, it is possible to circulate by selecting the opening and closing of the switching valve of the washing filtrate supply line and the opening and closing of the concentrated water discharge valve of the concentrated water discharge line. The amount of concentrated water discharged and the amount of bubbling in the raw water tank can be adjusted, and the concentration of the concentrated water can be kept at a moderate level to prevent clogging of the filtration membrane. Excellent.
Here, the switching valve only needs to be able to adjust the opening / closing amount in the washing filtrate supply line, but a solenoid valve is preferably used. The switching valve can adjust the supply amount of filtrate when supplying filtrate from the washing filtrate supply line, and also adjust the drainage of concentrated water and the drainage of concentrated water from the concentrate circulation line. be able to.

Invention of Claim 3 is a water purifier of

Claim

1 or 2, Comprising: The said filtered water tank is connected upstream and the said filtrate water tank of the said filtrate drain valve of the said filtrate drain line, and the said filtrate water is used. It has the structure provided with the filtrate circulating line which has the filtrate circulating pump to circulate.
With this configuration, in addition to the operation of the first or second aspect, the following operation is provided.
(1) Connect the filtrate water tank upstream with the filtrate drain valve of the filtrate drain line and have a filtrate circulating pump to circulate the filtrate, so circulate the filtrate and filter it on the inner wall of the filtrate drain line. It can prevent the adhesion of minerals in the water and is excellent in maintainability.
Here, the filtrate circulating pump may be any pump that can suck and circulate filtrate from the filtrate tank.
In addition, by providing a filtered water intake line that branches from the downstream side of the filtered water discharge line and the filtered water circulation line, the required amount of filtered water can be taken out using the power of the filtered water circulation pump. It can be supplied to and has excellent energy savings.

Invention of Claim 4 is a water purification apparatus of Claim 3, Comprising: It branches from the said filtrate water supply valve of the said filtrate water supply line for washing | cleaning from the downstream, and is connected to the said filtrate water tank, and the said filtration It has the structure provided with the line for filtered water bubbling which has the filtration water side bubble generation part which bubbles the inside of a water tank.
With this configuration, in addition to the operation of the third aspect, the following operation is provided.
(1) A filtration water bubbling line having a filtrate water bubble generating section that branches from the filtrate water supply valve downstream from the filtrate water supply valve and is connected to the filtrate water tank and bubbles in the filtrate water tank. Because the filtered water bubbled in the filtered water tank can be used as washing water, substances such as colloids and sparingly soluble salts adhering to the filtration membrane can be peeled off by an oxidative action, and by chemical reaction In addition to improving the cleaning efficiency, it is possible to suppress the deterioration of the filtration membrane and to have a long life.
Here, the filtered water-side bubble generating unit may be anything that can generate bubbles, but the negative pressure generated when the filtered water is discharged from the filtered water bubbling line, Those that suck air into a drain pipe to generate bubbles are preferably used. This is because drainage energy can be used effectively, no special power is required, and energy saving is excellent.

Invention of Claim 5 is a water purifier of Claim 4, Comprising: The said raw | natural water side bubble generation part and the said filtrate water side bubble generation part are a cylindrical liquid inflow pipe, and the said liquid inflow pipe A cylindrical liquid outflow pipe that is provided on the downstream side and has an inner diameter larger than the inner diameter of the liquid inflow pipe, and a plurality of air introduction pipes that are formed in the peripheral wall on the upstream side of the liquid outflow pipe and communicate with the liquid outflow pipe. And a hole.
With this configuration, in addition to the operation of the fourth aspect, the following operation is provided.
(1) A cylindrical liquid outflow in which the raw water side bubble generating part and the filtrate water side bubble generating part are connected to the cylindrical liquid inflow pipe and the downstream side of the liquid inflow pipe and have an inner diameter larger than the inner diameter of the liquid inflow pipe Since it has a plurality of air introduction micropores that are drilled in the peripheral wall on the upstream side of the pipe and the liquid outflow pipe and communicate with the liquid outflow pipe, the concentrated water and filtered water flowing in from the liquid inflow pipe pass through the liquid outflow pipe As a result, the pressure inside the liquid outflow pipe becomes lower than the outside, and external air is sucked into the liquid outflow pipe from the air introduction micropores, and is mixed and stirred with the concentrated water and filtered water flowing inside. Filtered water can be easily bubbled.
(2) Bubbling can be performed using the drainage energy of the concentrated water and filtered water that passes through the concentrated water discharge line and the filtered water bubbling line. The device can be simplified and the size can be reduced, and the space is saved.

Here, the diameters of the liquid inflow pipe, the liquid outflow pipe, and the air introduction microhole can be appropriately selected according to the flow rate (flow velocity) of the fluid passing through the inside, but the inner diameter of the liquid outflow pipe is that of the liquid inflow pipe. The inner diameter of the air introduction micropore is preferably 0.05 to 0.2 times the inner diameter of the liquid outflow pipe.
As the inner diameter of the liquid outflow pipe becomes smaller than twice the diameter of the liquid inflow pipe, the gap formed between the fluid passing through the liquid outflow pipe and the inner wall surface of the liquid outflow pipe becomes smaller (the air layer becomes smaller). The amount of air sucked from the air introduction micropores decreases, and bubbles tend to be less likely to be generated, and passes through the liquid outflow pipe as it becomes larger than 5 times the diameter of the liquid inflow pipe. The fluid velocity drops below the pipe resistance, making it difficult for negative pressure to occur, reducing the amount of air sucked in, and the gap formed between the fluid passing through the liquid outlet pipe and the inner wall surface of the liquid outlet pipe Is large (the air layer is thick), the fluid passing through the liquid outflow pipe and the air sucked from the air introduction micropores are difficult to mix and stir, and the amount of bubbles generated tends to decrease, both of which are preferable. Absent.

As the inner diameter of the air introduction microhole becomes smaller than 0.05 times the inner diameter of the liquid outflow pipe, the workability is lowered and clogging is likely to occur, and the stability of bubble generation tends to be reduced. As the pressure becomes larger than 0.2 times the inner diameter of the liquid outflow pipe (= equal to the diameter of the liquid inflow pipe), the pressure difference between the inside and outside of the liquid outflow pipe becomes smaller, and the fluid passing through the liquid outflow pipe And air are less likely to be mixed and stirred, and the amount of bubbles generated tends to decrease, which is not preferable.
The cross-sectional shapes of the liquid inflow pipe and the liquid outflow pipe may be uniform in the longitudinal direction, but various combinations can be selected as necessary. From the upstream end side to the downstream end side of the liquid outflow pipe The cross-sectional area may be gradually reduced toward the bottom, or the cross-sectional area may be gradually increased from the upstream end side of the liquid inflow pipe toward the downstream end side of the liquid outflow pipe. In particular, when the cross-sectional area of the liquid outflow pipe is gradually enlarged from the upstream end side toward the downstream end side, turbulent flow is generated inside the liquid outflow pipe, and the suction force of the air introduction micropore is increased. Bubbling (aeration) performance can be improved.

Invention of Claim 6 is a water purifier of any one of Claims 1 thru | or 5, Comprising: The said filtration part is two or more filtration membranes from which the performance arrange | positioned in parallel, A merging pipe connecting the filtration side of each of the filtration membranes and the filtrate drainage line, and a filtrate amount adjusting valve disposed in each of the junction pipes, and a conductivity meter in the filtrate drainage line. It has an arranged configuration.
With this configuration, in addition to the operation of any one of claims 1 to 5, the following operation is provided.
(1) The filtration unit is arranged in two or more filtration membranes arranged in parallel, a merging pipe connecting the filtration side of each filtration membrane and the filtrate discharge line, and each merging pipe And an electric conductivity meter on the filtrate discharge line, so that the conductivity of the filtrate discharged from the filtration unit can be measured with the conductivity meter. By adjusting the opening of the water volume adjustment valve or selectively switching between opening and closing, it is possible to keep the purified water (conductivity) optimally according to the purpose and application. It is excellent in filtration efficiency and energy saving.

Here, as a kind of filtration membrane arrange | positioned in parallel, an ultrafiltration membrane, a reverse osmosis membrane, a nano membrane, a hollow fiber membrane, etc. can be used in combination.
When a reverse osmosis membrane is used as one of the filtration membranes in the filtration section, RO water obtained by filtration through the reverse osmosis membrane can be used as washing filtered water, such as bacteria adhering to the raw water side of the filtration membrane It is possible to remove the deposits reliably and efficiently, and the cleaning efficiency is excellent.

Invention of Claim 7 is a water purifier of Claim 6, Comprising: The raw | natural water side connection which the said filtration part connects the raw | natural water side of two said filtration membranes in which the performance arrange | positioned in parallel differs It has the structure provided with the pipe | tube and the on-off valve arrange | positioned at the said raw | natural water side connection pipe.
With this configuration, in addition to the operation of the sixth aspect, the following operation is provided.
(1) Since the filtration unit has a raw water side connection pipe connecting the raw water sides of two filtration membranes arranged in parallel and having different performances, and an on-off valve arranged in the raw water side connection pipe, By closing the filtrate discharge valve of the filtrate drain line, the filtered water filtered through the high-performance filtration membrane out of the two filtration membranes has low performance through the confluence pipe by the pressure of the filtrate circulating pump It can be sent to the filtration side of the filtration membrane for cleaning, and is excellent in cleaning efficiency and long life of the filtration membrane.
(2) When washing the low-performance filtration membrane by closing the filtrate discharge valve and the on-off valve, the filtered water supply valve is opened, so that the filtrate filtered by the high-performance filtration membrane is added to the filtrate water tank. Stored filtered water is supplied from the filtered water circulation pump, and with a large amount of mixed water mixed with them, low performance filtration membranes can be washed from the filtration side, which is excellent in workability and certainty of filtration membrane cleaning. .
(3) With the raw water supply pump and the filtrate circulating pump being driven, the raw water supply valve of the raw water supply line, the filtrate discharge valve of the filtrate discharge line, and the concentrate discharge valve of the concentrate discharge line are closed, and the filtrate supply line for washing By opening the filtered water supply valve and switching valve, the filtrate water stored in the filtrate water tank is led from the filtrate water circulation line to the filtrate water discharge line and washing filtrate water supply line to the concentrated water circulation line, and then the raw water It can be supplied to the raw water side of the filtration section through the supply line. At this time, the raw water supply pump can be opened by opening an on-off valve arranged in the raw water side connecting pipe that connects the raw water sides of the two filtration membranes. The raw water side of the two filtration membranes can be circulated and washed with filtered water, and the filtration membrane is excellent in durability and long life. Then, by selecting the opening and closing of the concentrated water discharge valve as appropriate, a portion of the filtered water used for cleaning is discharged to the raw water tank, and cleaning is performed while exchanging the circulating filtered water with new filtered water. The cleaning efficiency and reliability are excellent.

According to the water purifier of the present invention, the following advantageous effects can be obtained.
According to invention of Claim 1, it has the following effects.
(1) By generating bubbles in the raw water side bubble generation unit and oxidizing and precipitating organic matter, iron, magnesium, manganese, calcium, etc., the supernatant liquid in the raw water tank is supplied to the filtration unit and efficient in a short time The filter membrane can be filtered and the raw water side of the filtration membrane can be washed using the filtered water filtered in the filtration section, greatly reducing or eliminating the use of chemicals. It is possible to provide a water purifier that is excellent in maintainability and environmental protection, that does not chemically deteriorate the filtration membrane, and that is excellent in durability and long life of the filtration membrane.

According to invention of Claim 2, in addition to the effect of Claim 1, it has the following effects.
(1) By controlling the opening and closing of the drainage line selector valve and the concentrated water discharge valve of the concentrated water discharge line, the amount of concentrated water discharged and the amount of bubbling in the raw water tank are controlled. Can be easily adjusted, the concentration of concentrated water can be appropriately maintained, and a water purifier excellent in filtration efficiency and energy saving can be provided.

According to invention of Claim 3, in addition to the effect of

Claim

1 or 2, it has the following effects.
(1) By circulating the filtered water with the filtered water circulation pump, it is possible to prevent minerals in the filtered water from adhering to the inner wall of the filtered water discharge line. It is possible to provide a water purifier excellent in operation efficiency and energy saving that can supply filtered water by using the power of.

According to invention of Claim 4, in addition to the effect of Claim 3, it has the following effects.
(1) By using the bubbling filtered water as washing water, the substances adhering to the filtration membrane can be reliably and efficiently peeled off by the oxidation action, and the cleaning efficiency is excellent and the filtration membrane is deteriorated. A water purifier excellent in long life and resource saving that can be suppressed can be provided.

According to invention of Claim 5, in addition to the effect of Claim 4, it has the following effects.
(1) Concentrated water or filtered water and air are mixed and stirred by effectively using the drainage energy (falling energy) of concentrated water or filtered water to suck in (involve) the surrounding air, and bubbling can be performed easily. Therefore, it is possible to provide a water purifier that is excellent in space saving and that can be reduced in size by reducing the size of the apparatus by simplifying the configuration.

According to invention of Claim 6, in addition to the effect of any one of Claims 1 thru | or 5, it has the following effects.
(1) By adjusting the amount of filtered water discharged from two or more filtration membranes with different performance arranged in parallel, it is possible to obtain filtered water with the optimum purity according to the purpose and application. Thus, it is possible to provide a water purifier excellent in filtration efficiency and energy saving that can prevent excess or deficiency of filtration.

According to invention of Claim 7, in addition to the effect of Claim 6, it has the following effects.
(1) By opening and closing the connecting pipe that connects the raw water sides of the two filtration membranes, the filtration side of one of the filtration membranes and the raw water side of both of the filtration membranes can be washed. Therefore, it is possible to provide a water purifier excellent in the maintenance performance of the filtration membrane, the efficiency of washing, and the durability of the filtration membrane, which can select the washing method of the filtration membrane.

The schematic diagram which shows the structure of the water purifier of Embodiment 1. Main part cross-sectional schematic diagram of the raw | natural water side bubble generation | occurrence | production part of the water purifier of Embodiment 1. FIG. The schematic diagram which shows the structure of the water purifier of Embodiment 2. The schematic diagram which shows the structure of the water purifier of Embodiment 3. The figure which shows the change of TMP (transmembrane differential pressure) when filtration and washing are repeated

The water purifier of the present invention will be described below with reference to the drawings.
(Embodiment 1)
FIG. 1 is a schematic diagram showing a configuration of a water purifier according to Embodiment 1.
In FIG. 1, 1 is the water purifier of the first embodiment, 2 is the raw water tank of the water purifier 1 where raw water collected from rivers, lakes, seas, etc. is supplied and stored by the supply pipe 2a, 2b is the bottom of the raw water tank 2 A discharge section for discharging the sediment precipitated in the raw water tank 2 and the concentrated raw water, 3 is a filtration of the water purification apparatus 1 provided with a filtration membrane such as an ultrafiltration membrane or a

reverse osmosis membrane

4, 4 is a raw water supply line connecting the raw water tank 2 and the filtration unit 3, 4a and 4b are pipelines of the raw water supply line 4 from the raw water tank 2 to the

filtration unit

3, and 5 is a raw water supply line 4 (pipe 4a). A raw water supply valve that uses an electromagnetic valve or the like that opens and closes the raw

water supply line

4, and 6 is a raw water supply that is provided in the raw water supply line 4 (pipe 4 b) to supply raw water from the raw water tank 2 to the filtration unit 3. The pump 7 is disposed in the raw water supply line 4 (pipe 4b). A pressure meter 8 that measures the supply pressure of water, 8 is a concentrated water circulation line of the water purification apparatus 1 that connects the upstream side of the raw water supply pump 6 of the raw water supply line 4 and the filtration unit 3 and circulates the concentrated water concentrated in the filtration unit 3. , 9 is connected to the filtration unit 3 and drains the filtered water filtered by the filtration unit 3, 9 a, 9 b, 9 c, 9 d are filtered water from the filtering unit 3 to the filtered water tank 10. Pipe line of the

discharge line

9, 10 is a filtrate water tank of the water purification device 1 that stores filtrate water discharged from the filtrate water discharge line 9, and 11 is provided in the filtrate water discharge line 9 (between the pipe lines 9 a and 9 b). An air chamber for preventing air from entering the filtration membrane when washing the filtration unit 3 by backflowing filtered water (during backwashing), 12 is disposed in the filtrate discharge line 9 (pipe 9b). Pressure meter that measures drainage pressure of filtered water, 1 Reference numerals a and 13b are arranged in parallel with the filtrate drain line 9, and one or both of them are opened to adjust the filtrate discharge pressure. Concentrated water discharge line 15 of the water purifier 1 for branching out from the concentrated water discharge line 14 for discharging the concentrated water to the raw water tank 2. Reference numeral 16 denotes a check valve disposed downstream of the concentrated water discharge valve 15 of the concentrated water discharge line 14 to prevent the backflow of the concentrated water, and reference numeral 17 denotes the concentrated water discharge valve 15 and the check of the concentrated water discharge line 14. A raw water-side bubble generating section disposed downstream of the valve 16 and bubbling in the

raw water tank

2, 18 is branched from the filtered water discharge valves 13 a and 13 b of the filtered water discharge line 9 from the upstream side (pipe 9 c), and concentrated water is circulated. Concentrated water in line 8 The filtered filtrate supply line 18a, 18b, 18c of the water purifier 1 is connected to the concentrated water circulation line 8 downstream of the branch line with the discharge line 14 and supplies filtered water as washing water. A pipe 19 of the washing filtrate supply line 18 that branches and reaches the concentrated water circulation line 8 is an electromagnetic valve 19 that is disposed in the washing filtrate supply line 18 (pipe 18a) and opens and closes the washing filtrate supply line 18. The filtered water supply valve 20 and the like are disposed downstream of the filtered water supply valve 19 (pipe 18 c) of the washing filtrate supply line 18 and switch between discharging concentrated water and supplying washing filtrate. A switching valve 21 using a solenoid valve or the like is branched from the washing filtrate supply line 18 (between the pipes 18b and 18c) between the filtrate supply valve 19 and the switch valve 20 and connected to the raw water tank 2. Drainage line of the water purifier 1, 1a is a drainage adjusting unit using a pressure regulating valve such as a spring check valve that adjusts the pressure of drainage and is disposed in the drainage line 21, and 21b is disposed in a pipe line 18b of the filtered water supply line 18 for washing. A check valve 22 for preventing the concentrated water discharged from the passage 18 c from flowing into the filtrate water tank 10 through the pipe 18 b is provided downstream of the filtrate water supply valve 19 of the washing filtrate water supply line 18. The filtered water bubbling line 23 of the water purification apparatus 1 branched from the side (between the pipes 18a and 18b) and connected to the filtered water tank 10 is provided in the filtered water bubbling line 22 and passes through the filtered water tank 10. The filtered water side bubble generating unit 24 to be bubbled, 24 is the filtered water circulation of the purified water device 1 that connects the filtered water discharge valve 13a, 13b upstream of the filtered water discharge line 9 (between the pipe lines 9b and 9c) and the filtered water tank 10. line, 5 is a filtered water circulation pump that circulates filtered water in the filtered

water circulation line

24, and 26 branches from the filtered water discharge valves 13 a and 13 b of the filtered water discharge line 9 from the downstream side (pipe 9 d) and is filtered outside the system. A filtered water intake line 26a for supplying water, 26a is a filtered water intake switching valve disposed at a branch position between the conduit 9d of the filtered water discharge line 9 and the filtered

water intake line

26, and 27 is a concentrated water discharge line 14. The waste water line 27a is disposed at a branch position between the concentrated water discharge line 14 and the waste water line 27 to prevent the concentrated water from being drained out of the system and concentrated in the raw water tank 2 if necessary. This is a wastewater switching valve for switching between discharge of concentrated water to the raw water tank 2 and wastewater to the outside of the system.
In addition, you may take raw water directly from a river, a lake, the sea, etc., without using the raw water tank 2, and supply it to the filtration part 3. FIG.

Operation | movement of the water purifier comprised as mentioned above is demonstrated.
First, the operation during filtration will be described.
In FIG. 1, by opening the raw water supply valve 5 and driving the raw water supply pump 6, the raw water sucked from the raw water tank 2 is supplied to the filtration unit 3 through the raw water supply line 4 (pipe lines 4a and 4b). .
By opening one or both of the filtrate discharge valves 13a and 13b of the filtrate discharge line 9 and closing the filtrate supply valve 19 of the filtrate supply line 18 for washing, the filtrate filtered by the filtration unit 3 is filtered water. It is discharged to the filtrate water tank 10 through the discharge line 9 (pipe lines 9a to 9d). In this embodiment, the filtered water discharge line 9 is provided with two filtered water discharge valves 13a and 13b, and one or both are opened to adjust the pressure. However, the opening degree (pressure) is arbitrary. In the case of using an arbitrary valve that can be set to 1, one is sufficient.
On the other hand, the concentrated water concentrated without being filtered by the filtration unit 3 returns to the raw water supply line 4 (pipe 4b) through the concentrated water circulation line 8 and is circulated. At this time, a part of the circulated concentrated water is discharged to the raw water tank 2 by opening the concentrated water discharge valve 15 of the concentrated water discharge line 14 and the switching valve 20 of the washing filtrate supply line 18 as necessary. To prevent excessive concentration of concentrated water. In addition, by discharging concentrated water from the concentrated water discharge line 14 and bubbling the inside of the raw water tank 2 with the raw water side bubble generating unit 17, it is possible to oxidize and precipitate organic matter, iron, magnesium, manganese, calcium and the like. The supernatant liquid in the raw water tank 2 can be supplied to the filtration unit 3 to shorten the time required for filtration.

Here, the structure of the raw | natural water side bubble generation part of the water purifier of Embodiment 1 is demonstrated.
FIG. 2 is a schematic cross-sectional view of an essential part of a raw water side bubble generating part of the water purifier according to the first embodiment.
In FIG. 2, 30 is a straight liquid inflow pipe of the raw water side bubble generating unit 17, 30 a is a liquid inflow hole drilled in the

liquid inflow pipe

30, and 31 is connected to the downstream side of the liquid inflow pipe 30 and has an inner diameter. A straight liquid outflow pipe 31a of the raw water side bubble generating section 17 formed larger in diameter than the liquid inflow pipe 30, 31a is a liquid outflow hole drilled in the liquid outflow pipe 31 and communicated with the liquid inflow hole 30a, 32 is a liquid outflow These are a plurality of air introduction micro holes formed in the peripheral wall on the upper end side of the part 31 and communicating with the liquid outflow hole 31a.
When the concentrated water flowing in from the liquid inflow hole 30a of the liquid inflow pipe 30 passes through the liquid outflow hole 31a of the liquid outflow pipe 31, the internal pressure of the liquid outflow pipe 31 becomes lower than the outside, and the external air becomes air. It is sucked into the liquid outflow pipe 31 from the introduction micropore 32, and mixed and stirred with concentrated water and filtered water flowing through the inside, and the concentrated water is bubbled.

The inner diameters of the liquid inflow pipe 30, the liquid outflow pipe 31, and the air introduction microhole 32 can be appropriately selected depending on the flow rate (flow velocity) of the concentrated water passing through the inside and the number of the air introduction microholes 32. In this embodiment, the inner diameter of the liquid outflow pipe 31 (= the diameter of the liquid outflow hole 31a) is formed to be twice to five times the inner diameter of the liquid inflow pipe 30 (= the diameter of the liquid inflow hole 30a). The inner diameter of the liquid outflow pipe 31 is 0.05 to 0.2 times the inner diameter of the liquid outflow pipe 31 (= the diameter of the liquid outflow hole 31a).
Although depending on the flow rate (flow velocity) of the concentrated water, as the inner diameter of the liquid outflow pipe 31 becomes smaller than twice the inner diameter of the liquid inflow pipe 30, the concentrated water passing through the liquid outflow hole 31a and the liquid outflow pipe 31 There is a tendency that the gap formed between the inner wall surface is small (the air layer is thin), the amount of air sucked from the air introduction microhole 32 is reduced, and bubbles are less likely to be generated. As the inner diameter becomes larger than 5 times, the speed of the concentrated water passing through the liquid outflow hole 31a decreases, it becomes difficult to generate negative pressure, the amount of air sucked in decreases, and the liquid outflow hole 31a passes through. The gap formed between the concentrated water and the inner wall surface of the liquid outflow pipe 31 is large (the air layer is thick), and the concentrated water passing through the liquid outflow hole 31a and the air sucked from the air introduction microhole 32 are mixed. Become difficult to stir This is because the bubble generation amount is found to have a tendency to become liable to lower.

Further, although depending on the number of air introduction microholes 32, as the inner diameter of the air introduction microholes 32 becomes smaller than 0.05 times the inner diameter of the liquid outflow pipe 31, workability deteriorates and clogging occurs. The liquid outflow pipe tends to be easily generated and the stability of the bubble generation tends to be lowered, and becomes larger than 0.2 times the inner diameter of the liquid outflow pipe 31 (= equivalent to the inner diameter of the liquid inflow pipe 30). This is because the pressure difference between the inside and the outside of 31 becomes small, and it becomes difficult for the concentrated water and air passing through the liquid outflow hole 31a to be mixed and stirred, so that the amount of bubbles generated tends to decrease. The number of air introduction microholes 32 is preferably 2 to 8, although it varies depending on the inner diameter of the liquid outflow pipe 31. When the number of air introduction micropores 32 is less than two, the amount of air sucked from the air introduction micropores 32 is reduced, and it becomes difficult for the concentrated water and air to be mixed and stirred, and the amount of generated bubbles is likely to decrease. When the number of air introduction micro-holes 32 is more than 8, the pressure difference between the inside and outside of the liquid outflow pipe 31 becomes small, and the concentrated water and air passing through the liquid outflow hole 31a are mixed and stirred. This is because it has been found that there is a tendency that the bubble generation amount tends to decrease and the durability of the liquid outflow pipe 31 tends to decrease.

In the present embodiment, the cross-sectional shapes of the liquid inflow pipe 30 and the liquid outflow pipe 31 are uniformly formed in the longitudinal direction, but the present invention is not limited to this, and various combinations can be selected as necessary. can do. For example, the cross-sectional area is gradually reduced from the upstream end side to the downstream end side of the liquid outflow pipe 31, or the cross-sectional area is gradually increased from the upstream end side of the liquid inflow pipe 30 toward the downstream end side of the liquid outflow pipe 31. May be enlarged. In particular, when the cross-sectional area of the liquid outflow pipe 31 is gradually enlarged from the upstream end side toward the downstream end side, turbulent flow is generated inside the liquid outflow pipe 31 and the suction force of the air introduction microhole 32 is increased. Thus, the bubbling (aeration) performance can be improved.

In addition, since the water purifier 1 is provided with the filtrate water circulation line 24, the filtrate water stored in the filtrate water tank 10 can be removed from the filtrate water discharge line 9 by driving the filtrate circulation pump 25 during filtration. It can be made to circulate between 9d and the filtrate water tank 10, and it can prevent that the mineral content etc. in filtrate water adhere to the pipe inner wall of the filtrate water discharge line 9. FIG.
Moreover, if the filtered water intake switching valve 26a of the filtered water intake line 26 is switched to the filtered water intake line 26 side, filtered water is supplied to the intake side (client side) outside the system using the power of the filtrate circulating pump 25. be able to.

Next, the operation during cleaning will be described.
The raw water supply valve 5 of the raw water supply line 4, the filtrate water discharge valves 13 a and 13 b of the filtrate discharge line 9 and the concentrated water discharge valve 15 of the concentrated water discharge line 14 are closed while the raw water supply pump 6 and the filtrate circulating pump 25 are driven. The filtrate water stored in the filtrate water tank 10 is opened from the filtrate water circulation line 24 to the pipeline 9c of the filtrate discharge line 9 by opening the filtrate water supply valve 19 and the switching valve 20 of the filtrate water supply line 18 for washing. It is led to the concentrated water circulation line 8 through the filtered filtered water supply line 18 (pipe lines 18a, 18b, 18c), and further supplied to the raw water side of the filtration unit 3 through the pipe line 4b of the raw water supply line 4. The filter membrane is washed with water. A part of the filtrate water that has passed through the filtrate water supply valve 19 passes through the filtrate water bubbling line 22 due to the difference between the circulation pressure of the raw water supply pump 6 and the circulation pressure of the filtrate water circulation pump 25. The filtered water tank 10 is bubbled by the action of the filtered water side bubble generating unit 23, and the filtered water is circulated through the filtered water circulation line 24. Thereby, since the bubbled filtered water can be used as the washing water, the substance adhering to the filtration membrane can be peeled off by an oxidizing action, and the washing efficiency by chemical reaction can be improved.
At this time, by opening the concentrated water discharge valve 15 of the concentrated water discharge line 14 as necessary, a part of the filtered water used for washing can be discharged to the raw water tank 2, and the circulating filtered water can be removed. Washing can be performed efficiently while replacing with new filtered water.

In addition, since the filtrate water side bubble generation part 23 has the same structure as the raw | natural water side bubble generation part 17, description is abbreviate | omitted.
As described above, when the raw water supply pump 6 and the filtrate circulating pump 25 are continuously driven throughout the filtration and washing, the raw water supply pump is compared with the case where the raw water supply pump 6 and the filtrate circulating pump 25 are intermittently operated. 6 and when the filtrate circulating pump 25 is stopped or re-driven, the load generated can be reduced, and the operation stability and the durability of the apparatus are excellent.
The air chamber 11 may be provided as necessary, and may be omitted.

The water purifier according to Embodiment 1 has the following action.
(1) A raw water tank 2 in which raw water is stored, a raw water supply line 4 having a raw water supply pump 6 and a raw water supply valve 5 that connect the raw water tank 2 and the filtration unit 3 and supply the raw water from the raw water tank 2 to the filtration unit 3. Then, the upstream side of the raw water supply line 6 of the raw water supply line 6 is connected to the filtration unit 3, and the concentrated water in which the solid particles are concentrated in the filtration unit 3 is circulated from the filtration unit 3 to the pipe 4 b of the raw water supply line 4. Since the water circulation line 8 is provided, it is possible to perform filtration while continuously operating the raw water supply pump 6 to circulate the concentrated water, and it is possible to reduce the load caused by stopping or restarting the raw water supply pump 6. Excellent operational stability.
(2) Since the concentrated water discharge line 14 having the concentrated water discharge valve 15 that branches from the concentrated water circulation line 8 and discharges the concentrated water to the raw water tank 2 is provided, the concentrated water that circulates through the concentrated water circulation line 8 as necessary. A part is discharged to the raw water tank 2 to prevent the concentrated water from being excessively concentrated, clogging of the filtration membrane can be reduced, and the filtration efficiency is excellent.
(3) By providing the raw water side bubble generating part 17 which is disposed downstream of the concentrated water discharge valve 15 of the concentrated water discharge line 8 and bubbles in the raw water tank 2, organic substances, iron, magnesium, manganese, calcium, etc. Since it can oxidize and precipitate, the supernatant liquid in the raw | natural water tank 2 can be supplied to a filtration part, can be filtered efficiently in a short time, and it is excellent in the efficiency of filtration.
(4) Branched from the filtered water discharge valve 13a, 13b upstream of the filtered water discharge line 13a, 13b (pipe 9c) and filtered downstream from the connection position with the concentrated water discharge line 14 of the concentrated water circulation line 8. By providing the washing filtrate supply line 18 having the filtrate supply valve 19 for supplying water as washing water, the raw water side of the filtration membrane can be washed with filtered water, so that no chemical solution is required or the chemical solution The amount used can be greatly reduced, it is excellent in environmental protection, the filtration membrane is not chemically deteriorated, and the filtration membrane is excellent in durability and long life.
(5) The switching valve 20 disposed on the downstream side of the filtrate water supply valve 19 of the washing filtrate supply line 18, and the washing filtrate supply line 18 branches between the filtrate water supply valve 19 and the switching valve 20. Since the drainage line 21 connected to the raw water tank 2 is provided, the filtration filtrate supply line 19 of the washing filtrate supply line 18 is closed during filtration, and the switching valve 20 is opened to open the filtration filtrate supply line 18 for washing. Concentrated water can be discharged from the drainage line 21 to the raw water tank 2 using a part (the pipe line 18c), so that the piping can be simplified and the apparatus can be miniaturized. Excellent.
(6) Since a part (pipe line 18 c) of the washing filtrate supply line 18 and the drainage line 21 are arranged in parallel with the concentrated water discharge line 14, they are arranged in the pipe line 18 c of the washing filtrate supply line 18. By selecting opening and closing of the provided switching valve 20 and opening and closing of the concentrated water discharge valve 15 of the concentrated water discharge line 14, the amount of concentrated water discharged from the concentrated water circulation line 8 to the raw water tank 2 and the raw water tank 2 are selected. The amount of bubbling inside can be adjusted, the concentration of the concentrated water can be kept moderate, and the filtration efficiency is excellent.
(7) The filtrate water discharge line 13 is connected upstream of the filtrate water discharge valves 13a and 13b (the pipe line 9c) and the filtrate water tank 10 and has a filtrate water circulation pump 25 for circulating the filtrate water. Thus, it is possible to prevent minerals in the filtered water from adhering to the inner walls of the pipes 9c and 9d of the filtered water discharge line 9, and the maintenance is excellent.
(8) Filtrated water bubbling having a filtered water side bubble generating unit 23 that branches from the filtered water supply valve 19 of the washing filtered water supply line 18 from the downstream side and is connected to the filtered water tank 10 to bubble inside the filtered water tank 10. By providing the line 22 for use, the filtered water bubbled in the filtered water tank 10 can be used as washing water, so that substances such as colloids and hardly soluble salts adhering to the filtration membrane are peeled off by an oxidizing action. It is possible to improve the cleaning efficiency by chemical reaction, suppress the deterioration of the filtration membrane, and have excellent long life.
(9) The raw water side bubble generating part 17 and the filtered water side bubble generating part 23 are connected to the liquid inflow part 30 having the liquid inflow hole 30a and the downstream side of the liquid inflow part 30 and have a larger diameter than the liquid inflow hole 30a. Since the liquid outflow part 31 having the liquid outflow hole 31a and the plurality of air introduction micro holes 32 which are formed in the peripheral wall on the upper end side of the liquid outflow part 31 and communicate with the liquid outflow hole 31a are provided, the liquid inflow of the liquid inflow part 30 Concentrated water or filtered water flowing in from the hole 30a passes through the liquid outflow hole 31a of the liquid outflow part 31, so that the pressure inside the liquid outflow part 31 becomes lower than the outside, and the external air becomes the air introduction microhole 32. Then, it is sucked into the liquid outflow portion 31 and mixed and stirred with the concentrated water and filtered water flowing inside, so that the concentrated water and filtered water can be easily bubbled.
(10) Bubbling can be performed by using the drainage energy of the concentrated water and filtered water passing through the concentrated water discharge line 14 and the filtered water bubbling line 22, and no power is required separately. The structure can be simplified and the apparatus can be miniaturized, and the space is saved.

(Embodiment 2)
FIG. 3 is a schematic diagram showing the configuration of the water purifier according to the second embodiment. In addition, the same code | symbol is attached | subjected to the thing similar to Embodiment 1, and description is abbreviate | omitted.
In FIG. 3, the water purifier 1a of the second embodiment is different from the first embodiment in that the filtration unit 3A has two filtration membranes 3a and 3b having different performances arranged in parallel, and the filtration membranes 3a and 3b. The raw water side connecting pipe 3c that connects the raw water sides of each other, the merging pipes 28a, 28b that connect the filtration side of each filtration membrane 3a, 3b and the conduit 9a of the filtered water discharge line 9, and each merging pipe 28a, It is the point provided with the electrical conductivity meter 35 arrange | positioned in the pipe line 9d of the filtrate water amount adjustment valves 29a and 29b arrange | positioned by 28b, and the filtrate water discharge line 9. FIG.

Although the basic operation at the time of filtration of the water purifier 1a of the second embodiment is the same as that of the first embodiment, the two filtration membranes 3a and 3b having different performances are arranged in parallel in the filtration unit 3A. While measuring and confirming the conductivity (purity) of the filtrate with the conductivity meter 35, the degree of opening of each of the filtrate adjustment valves 29a and 29b is adjusted to obtain filtrate with a desired conductivity (purity). be able to.
As the filtration membranes 3a and 3b, an ultrafiltration membrane, a reverse osmosis membrane, a nano membrane and the like can be used in combination. When a reverse osmosis membrane is used for one of the filtration membranes 3a and 3b of the filtration unit 3A, RO water obtained by filtration through the reverse osmosis membrane can be used as the filtration water for washing, and the filtration membranes 3a and 3b Deposits such as bacteria attached to the raw water side can be reliably and efficiently peeled off, resulting in excellent cleaning efficiency.
Further, by connecting the raw water sides of the filtration membranes 3a and 3b with the raw water side connecting pipe 3c, the pressure is increased on the raw water side of the filtration membrane (for example, reverse osmosis membrane) having the higher performance among the filtration membranes 3a and 3b. When the pressure increases, the pressure can be released to the raw water side of the lower performance filtration membrane (for example, ultrafiltration membrane) to prevent the filtration membrane from being damaged, and the filtration membrane is excellent in protection.

About the operation | movement at the time of washing | cleaning of the water purifier 1a of Embodiment 2, since it is the same as that of Embodiment 1, description is abbreviate | omitted.
In this embodiment, two types of filtration membranes 3a and 3b are arranged in parallel. However, three or more types of filtration membranes 3a and 3b may be arranged in parallel, and the raw water side connecting pipe 3c may be omitted.
Further, instead of providing the conductivity meter 35, the filtered water amount adjusting valves 29a and 29b may be opened and closed with a time difference by a delay timer or the like to adjust the filtered water amount in each of the filtration membranes 3a and 3b.

According to the water purifier in Embodiment 2, in addition to the action obtained in Embodiment 1, it has the following action.
(1) The filtration unit 3A includes two or more filtration membranes 3a and 3b having different performances arranged in parallel, and filtration water amount adjusting valves 29a and 29b arranged on the filtration side of the respective filtration membranes 3a and 3b. , And the conductivity meter 35 is disposed in the conduit 9d of the filtrate discharge line 9, so that the conductivity (purity) of the filtrate discharged from the filtration unit 3A is measured with the conductivity meter. The degree of opening of each filtered water volume adjustment valve 29a, 29b can be adjusted, and the conductivity (purity) of filtered water can be kept optimal according to the purpose, application, etc., preventing excessive or insufficient filtration. It is excellent in filtration efficiency and energy saving.

(Embodiment 3)
FIG. 4 is a schematic diagram illustrating the configuration of the water purifier according to the third embodiment. In addition, the same code | symbol is attached | subjected to the thing similar to

Embodiment

1 or 2, and description is abbreviate | omitted.
In FIG. 4, the water purifier 1b of the third embodiment is different from the second embodiment in that the filtration unit 3B is opened and closed disposed on the raw water side connecting pipe 3c that connects the raw water sides of the filtration membranes 3a and 3b. The point provided with the valve 3d and the point provided with the separation tank 4c connected to the tip of the pipe line 4a of the raw water supply line 4 and sunk in the raw water tank 2.
Since the operation | movement at the time of filtration of the water purifier 1b of Embodiment 3 is the same as that of Embodiment 2, description is abbreviate | omitted.

Cleaning (backwashing) from the filtration side of the water purifier 1b of Embodiment 3 will be described.
The filtration membrane 3a is a high performance filtration membrane such as a reverse osmosis membrane, and the filtration membrane 3b is a medium performance filtration membrane such as an ultrafiltration membrane having a lower performance than the filtration membrane 3a. With the discharge valve 15, the switching valve 20 and the filtrate adjustment valves 29a and 29b open, the on-off valve 3d, the raw water supply valve 5, the filtrate discharge valves 13a and 13b and the filtrate supply valve 19 of the filtrate discharge line 9 are By closing, the filtrate filtered through the high-performance filtration membrane 3a out of the two filtration membranes 3a and 3b is sent to the filtration side of the low-performance filtration membrane 3b by the pressure of the filtrate circulating pump 25, Washing (back washing) can be performed.
At this time, when the filtrate water supply valve 19 is opened, filtration with low performance is performed with a large amount of mixed water obtained by mixing the filtrate filtered through the high-performance filtration membrane 3a and the filtrate stored in the filtrate tank 10. The membrane 3b can be washed (backwashed) from the filtration side.
In addition, you may provide a filtered water shut-off valve in the pipe line 9a of the filtered water discharge line 9 on the downstream side of the filtered water amount adjusting valves 29a and 29b. In this case, if the filtrate shut-off valve is closed, the filtrate filtered through the filtration membrane 3a is sent directly to the filtration side of the filtration membrane 3b through the merge pipes 28a and 28b (filtrate adjustment valves 29a and 29b). Washing (back washing) can be performed, and cleaning reliability and reliability are excellent.
As described above, the cleaning method for the filtration membranes 3a and 3b can be appropriately selected by opening and closing the on-off valve 3d, and the versatility is excellent.
Moreover, although the basic operation | movement at the time of normal washing | cleaning (washing | cleaning from the raw | natural water side of the filtration membranes 3a and 3b) in the water purifier 1b of Embodiment 3 is the same as that of Embodiment 1, filtered water is the filtration part 3B. When the raw water side is supplied, by opening the on-off valve 3d disposed in the raw water side connecting pipe 3c, the raw water side of the two filtration membranes 3a and 3b is circulated and washed with filtered water by the raw water supply pump 6. be able to. As in the first embodiment, by appropriately opening the concentrated water discharge valve 15 of the concentrated water discharge line 14, a part of the filtrate used for washing is discharged to the raw water tank 2 and is being circulated. Washing can be performed while replacing the filtered water with new filtered water.

The separation tank 4c is formed in a cylindrical shape with a bottom, and a plurality of through holes are formed in the peripheral wall surface. As a result, SS (floating matter) in the raw water does not easily enter the inside of the separation tank 4c from the through hole, is separated at the outer peripheral surface of the separation tank 4c, settles in the raw water tank 2, and is supplied to the filtration unit 3B. By reducing the amount of SS in the water, the load on the filtration unit 3B can be reduced, and the efficiency of filtration and the long life of the filtration membranes 3a and 3b can be improved.
In addition, the hole diameter of a through-hole can be suitably selected according to the surface tension of water and the particle size of SS.

According to the water purifier in Embodiment 3, in addition to the action obtained in

Embodiment

1 or 2, it has the following action.
(1) The raw water side connection pipe 3c that connects the raw water sides of the two filtration membranes 3a and 3b having different performances arranged in parallel with the filtration unit 3B, and the on-off valve provided in the raw water side connection pipe 3c 3d, the open / close valve 3d, the raw water supply valve 5, and the filtered water discharge line 9 are filtered while the concentrated water discharge valve 15, the switching valve 20 and the filtered water amount adjusting valves 29a and 29b of the concentrated water discharge line 14 are opened. By closing the water discharge valves 13a and 13b and the filtrate supply valve 19, the filtrate filtered through the high-performance filtration membrane 3a out of the two filtration membranes 3a and 3b is filtered by the pressure of the filtrate circulation pump 25. Further, it can be sent to the filtration side of the low-performance filtration membrane 3b through the merging pipes 28a and 28b, and washing can be performed, and the washing efficiency and the long life of the filtration membrane are excellent.
(2) When the concentrated membrane discharge valve 15, the switching valve 20 and the filtrate amount control valves 29a and 29b are opened and the filtrate drain valves 13a and 13b and the on-off valve 3d are closed to wash the low performance filtration membrane 3b, filtration is performed. By opening the water supply valve 19, the filtered water stored in the filtered water tank 10 is supplied from the filtered water circulation pump 25 to the filtered water filtered by the high-performance filtration membrane 3a, and a large amount of mixing is performed. The filter membrane 3b having low performance can be washed from the filtration side with water, and the workability and certainty of filtration membrane cleaning are excellent.
(3) The raw water supply valve 6 of the raw water supply line 4, the filtered water discharge valves 13 a and 13 b of the filtered water discharge line 9, and the concentrated water discharge valve of the concentrated water discharge line 18 while driving the raw water supply pump 6 and the filtrate circulating pump 25. 15 is closed, and the filtrate water supply valve 19 and the switching valve 20 of the washing filtrate supply line 18 are opened, so that filtrate water stored in the filtrate water tank 10 is piped from the filtrate circulation line 24 to the filtrate discharge line 9. The water is fed to the concentrated water circulation line 8 through the passage 9c and the filtered filtered water supply line 18 (pipe lines 18a, 18b, 18c), and further supplied to the raw water side of the filtration unit 3B through the pipe line 4b of the raw water supply line 4. However, at this time, the raw water supply pump 6 allows two filters to be opened by opening the on-off valve 3d disposed in the raw water side connecting pipe 3c that connects the raw water sides of the two filtration membranes 3a and 3b. Film 3a, can the raw water side of the 3b circulating washed with filtered water, filtration membranes 3a, 3b durability, excellent in long life.

Hereinafter, the present invention will be specifically described by way of examples. The present invention is not limited to these examples.
Using the water purifier described in Embodiment 1, the water permeability recovery of the filtration membrane by washing was evaluated.
As a method of evaluation, filtration and washing were repeated for 140 hours for 14 days for the water purifier 1, and the raw water-side circulation pressure and the filtration-side filtration pressure of the filtration unit 3 were measured during that time.
An ultrafiltration membrane (Dializer KF-15 manufactured by Kawasumi Chemical Co., Ltd.) was used as the filtration membrane. The raw water supply line uses a silicon tube with an inner diameter of 3 mm, the raw water side line length is 4 m, the quantitative filtration pressure is 2.5 kPa, the membrane pressure loss is 20 Pa, and the viscosity of the raw water (test water) is 0.002 Pa · s. Quantitative filtration was performed using a flow rate of about 10 × 10 ⁻⁶ m ³ / s obtained from Poiseuille's law as the flow rate of the raw water supply pump. The flow rate of the filtrate circulating pump was about 7 × 10 ⁻⁶ m ³ / s.
In addition, the raw water (test water) used for the evaluation was adjusted so that the humic acid concentration was about 10 times that of the natural world by adding humic acid to the soil water along the coast of the Onga River. It is added.

The result is shown in FIG.
FIG. 5 is a diagram showing changes in TMP (transmembrane pressure difference) when filtration and washing are repeated.
In FIG. 5, the horizontal axis is the number of days elapsed from the start of use, the vertical axis is the pressure, what is plotted with a black circle is the raw water-side circulation pressure, and what is plotted with the white square is the filtration-side filtration pressure. In FIG. 4, only the pressure fluctuation measured during filtration or washing is plotted, and while the apparatus is at rest (one day of filtration or washing is finished, then washing or filtration is started). Is not included.
The period during which the raw water side circulation pressure is high and the filtration side filtration pressure is low is the state during filtration, and the period during which the raw water side circulation pressure is low and the filtration side filtration pressure is high represents the state during washing. Yes.
From FIG. 5, even if the water purifier 1 is driven for 14 days for 140 hours, there is almost no change in TMP (transmembrane pressure difference), and the water permeability (filtration efficiency) of the filtration membrane is maintained almost constant by washing. I understand that.
As a result, the water purifier of the present invention having a cleaning function with the bubbling filtered water can realize sufficient water permeability recovery by circulating cleaning, and the filter membrane has a long life, durability, and environmental protection. It can be said that it is excellent.

The present invention has a simple structure and suppresses bacterial growth by removing impurities and bacteria adhering to the filter membrane reliably and efficiently without using chemicals or by greatly reducing the amount of chemicals used. Excellent filtration membrane cleaning efficiency and environmental protection, can greatly improve the durability, long life, and maintainability of the filtration membrane, prevent deterioration of filtration performance over time, and stable operation In addition to being excellent in performance, filtration efficiency and energy saving, the purity of filtered water can be easily adjusted by controlling the electrolyte components contained in the filtered water, and the filtered water can be washed in drinking water, food, dishes, etc. By providing a water purifier with excellent versatility that can be used for a wide range of uses such as water, it can greatly contribute to the elimination of water shortages.

1, 1a, 1b Water purification device 2 Raw water tank 2a Supply pipe 2b Discharge part 3, 3A, 3B Filtration part 3a, 3b Filtration membrane 3c Raw water side connection pipe 3d Open / close valve 4 Raw water supply lines 4a, 4b, 9a, 9b, 9c 9d, 18a, 18b, 18c Pipe line 4c Separation tank 5 Raw water supply valve 6 Raw water supply pump 7, 12 Pressure meter 8 Concentrated water circulation line 9 Filtrated water discharge line 10 Filtrated water tank 11 Air chamber 13a, 13b Filtrated water discharge valve 14 Concentration Water discharge line 15 Concentrated water discharge valve 16, 21 b Check valve 17 Raw water side bubble generation part 18 Washing filtrate supply line 19 Filtration water supply valve 20 Switching valve 21 Drain line 21 a Drain adjustment part 22 Filtration water bubbling line 23 Filtration Water-side bubble generating part 24 Filtrated water circulation line 25 Filtrated water circulation pump 26 Filtered water intake line 26a Filtered water intake switching valve 27 Wastewater line 27a Wastewater switching valves 28a and 28b Merge pipes 29a and 29b Filtration water amount adjustment valve 30 Liquid inflow pipe 30a Liquid inflow hole 31 Liquid outflow pipe 31a Liquid outflow hole 32 Air introduction microhole 35 Conductivity meter

Claims

A circulation type water purifier that performs partial filtration with a filtration membrane disposed in a filtration unit,
A raw water tank in which raw water is stored, a raw water supply line having a raw water supply pump and a raw water supply valve that connect the raw water tank and the filtration unit and supply the raw water from the raw water tank to the filtration unit, and the raw water supply line The concentrated water circulation line for connecting the upstream side of the raw water supply pump and the filtration unit to circulate the concentrated water concentrated in the filtration unit, and discharging the filtered water connected to the filtration unit and filtered by the filtration unit A filtrate drain line having a filtrate drain valve, a filtrate tank storing the filtrate discharged from the filtrate drain line, and a concentration branching off from the concentrate circulation line and discharging the concentrate to the raw water tank A concentrated water discharge line having a water discharge valve, and a raw water side bubble that is disposed downstream of the concentrated water discharge valve of the concentrated water discharge line and bubbles in the raw water tank The filtrate is connected to the concentrated water circulation line downstream from the branch position between the raw part and the concentrated water discharge line of the concentrated water circulation line after branching from the upstream side of the filtered water discharge valve of the filtered water discharge line A water purification apparatus comprising: a filtrate water supply line for washing having a filtrate water supply valve for supplying water as washing water.
A switching valve disposed downstream of the filtrate water supply valve in the washing filtrate supply line, and the raw water branched from the washing filtrate supply line between the filtrate water supply valve and the switching valve. The water purifier according to claim 1, further comprising a drain line connected to the tank.
The filtered water circulation line which has the filtered water circulation pump which connects the upstream side and the filtrate water tank from the filtrate water discharge valve of the filtrate water discharge line, and circulates the filtrate water is characterized by the above-mentioned. The water purifier according to 1.
A filtration water bubbling line having a filtrate water-side bubble generating part that branches from the filtrate water supply valve downstream of the filtrate water supply valve and is connected to the filtrate water tank and bubbles in the filtrate water tank. The water purifier according to claim 3.
The raw water side bubble generating section and the filtrate water side bubble generating section are connected to a cylindrical liquid inflow pipe and a downstream side of the liquid inflow pipe, and a cylindrical liquid having an inner diameter larger than the inner diameter of the liquid inflow pipe. 5. The water purifier according to claim 4, comprising an outflow pipe and a plurality of air introduction micropores that are formed in a peripheral wall on the upstream side of the liquid outflow pipe and communicate with the liquid outflow pipe.
The filtration unit is arranged in parallel at two or more filtration membranes having different performances, a merging pipe connecting the filtration side of each of the filtration membranes and the filtrate discharge line, and each merging pipe A water purifier according to any one of claims 1 to 5, further comprising an electric conductivity meter disposed in the filtrate drain line.
The filtration unit was provided with a raw water side connection pipe connecting the raw water sides of the two filtration membranes having different performance arranged in parallel, and an on-off valve arranged in the raw water side connection pipe. The water purifier according to claim 6.