JP2014217830A - Ultrapure water production system and ultrapure water production and supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ultrapure water production system and an ultrapure water production and supply system which do not contaminate piping including and after a particulate removal membrane device of the ultrapure water production system, and an ultrapure water supply piping system at the time of washing sterilization and sterilization, and can supply ultrapure water of good water quality to a water use point in a short time after completion of the washing sterilization and the sterilization.SOLUTION: In an ultrapure water production system which includes at least a tank 11, a pump 12, a heat exchanger 13, an ultraviolet device 14, an ion exchanger 15, and a first particulate removal membrane device 16, a second particulate removal membrane device 17 is provided in parallel to the first particulate removal membrane device 16, and water supply switching means is provided which switches water supply between the first and second particulate removal membrane devices 16, 17.

Description

  The present invention relates to an ultrapure water production system and an ultrapure water production supply system. Specifically, the present invention relates to a system capable of supplying ultrapure water with good water quality to a water use point (use point) in a short time after a cleaning sterilization step or a sterilization step.

  In the electronics industry, ultrapure water is used as cleaning water for components. Ultrapure water quality applied to semiconductor manufacturing plants and wafer manufacturing plants is strict, for example, resistivity (specific resistance value): 18.2 MΩ · cm or more, fine particles: particle size of 50 nm or more, 500 / L or less, viable bacteria: 1 piece / L or less, TOC (Total Organic Carbon): 1 μg / L or less, Total silicon: 0.05 μg / L or less, Metals: 0.1 ng / L or less, Ions: 5 ng / L or less.

  Fine particles such as dust, silica, and aluminum in the air mixed in the system during construction (new establishment, expansion, modification) or maintenance of the ultrapure water production system, particles contained in water such as dead bodies of bacteria, iron rust, In addition, fine particles made of shavings such as membranes and piping generated in the manufacturing process remain in the system. The fine particles are excluded from the system system, and cleaning with an alkaline solution is performed so that the number of fine particles having a particle diameter of 50 nm or more in ultrapure water is 1000 / L or less (for example, Patent Document 1).

  Moreover, the sterilization method of the ultrapure water manufacturing system for suppressing the living microbe in ultrapure water is proposed (for example, patent documents 2, 3).

  A cleaning and sterilizing method for an ultrapure water production system in which the inside of an ultrapure water production system is washed with an alkaline solution and then washed with a hydrogen peroxide solution has been proposed (Patent Document 4).

  Moreover, the ultrapure water production which performs the washing | cleaning sterilization process which consists of the alkali washing process which wash | cleans at least one in the system of an ultrapure water production system with an alkaline solution, and the process sterilized with a sterilization water after this alkali washing twice or more A system sterilization method has also been proposed (Patent Document 5).

  The principle of fine particle removal by the alkaline solution is as follows.

  That is, the fine particles adhering to the pipe or the like of the ultrapure water production system are electrically or electrostatically attached to the pipe or the like due to the surface potential. In general, the surface potential of fine particles in a solution such as a cleaning solution changes depending on the liquid property, but particularly changes significantly by changing the pH of the solution. By changing the pH of the liquid to the alkaline side, the fine particles are negatively charged and the charge is also increased. On the other hand, organic polymer materials such as PVC (polyvinyl chloride) and PPS (polyphenylene sulfide) constituting the piping system of an ultrapure water production system cause a change in surface potential even when the pH of the liquid changes. First, it has a negative charge regardless of the pH change of the liquid in contact. Therefore, by changing the pH of the liquid in contact with alkalinity, the negatively charged fine particles are electrically repelled from the system constituent material, making it easier to peel off and remove.

  This peeling and removing action is sufficiently exerted even when the concentration of the alkaline solution used as the cleaning liquid is low (for example, several tens mg / L). Therefore, the concentration of the cleaning liquid can be reduced. Therefore, the ratio of the cleaning liquid component remaining in the system is reduced, and an increase in TOC due to this component is also suppressed. As a result, the cleaning operation can be completed in a short time, and the quality of the ultrapure water produced by the ultrapure water production system becomes good within a short time after the cleaning operation.

  As described above, the method for cleaning an ultrapure water production system using an alkaline solution is excellent in the ability to remove fine particles, and the fine particles adhering to the ultrapure water production system can be quickly peeled off and removed. In addition, since the cleaning liquid has a low concentration, the components in the cleaning liquid remain after the cleaning and the TOC is rarely increased. For this reason, it is possible to perform a cleaning operation in a short time.

  In patent document 4, after washing | cleaning by this alkaline solution, hydrogen peroxide is further inject | poured and sterilized, thereby enabling efficient cleaning and sterilization. Moreover, in patent document 5, the metal in an ultrapure water manufacturing system system is performed by performing the washing | cleaning sterilization process which performs the alkali washing | cleaning process wash | cleaned with an alkaline solution, and the process sterilized with sterilization water after this alkali washing | cleaning twice or more. Enables highly efficient removal of organic matter, fine particles, and live bacteria.

JP 2000-317413 A JP 2002-166283 A JP 2004-275881 A JP 2002-192162 A No. 2008/123351

  In semiconductor manufacturing factories and wafer manufacturing factories, cleaning sterilization or sterilization after construction (new establishment, expansion or modification) and sterilization after maintenance are carried out using the apparatus of the ultrapure water production system.

  Conventional clean sterilization and sterilization are sufficient if the number of fine particles having a particle size of 50 nm or more is 1000 / L or less, but the number of particles having a particle size of 50 nm or more is required to be 500 / L or less. It has become a situation that can not be satisfied with ultrapure water.

  The present invention uses ultra-pure water with good water quality in a short time after the completion of cleaning, sterilization and sterilization of the fine particle removal membrane device of the ultra-pure water production system and the subsequent piping and ultra-pure water supply piping system. An object of the present invention is to provide an ultrapure water production system and an ultrapure water production supply system that can be supplied to points (use points).

  The ultrapure water production system of the present invention is an ultrapure water production system comprising at least a tank, a pump, a heat exchanger, an ultraviolet ray device, an ion exchange device, and a first fine particle removal membrane device. A second particulate removal membrane device is provided in parallel with the membrane device or between the final pump of the ultrapure water production system and the first particulate removal membrane device.

  In one aspect of this ultrapure water production system, the second particulate removal membrane device is provided in parallel with the first particulate removal membrane device, and only the first particulate removal membrane device passes water, the second particulate removal membrane. Flow path switching means is provided for switching the flow of water only to the apparatus and switching the flow of water to both the first and second particulate removal membrane apparatuses.

In another aspect of this ultrapure water production system, the second particulate removal membrane device is provided in parallel with the ion exchange device, and only the ion exchange device passes water, only the second particulate removal membrane device passes water, Flow path switching means for switching water flow to both the ion exchange device and the second particulate removal membrane device is provided.
In this ultrapure water system, regardless of the position of the second particle removal membrane device, the water flow only through the first particle removal membrane device, the water flow through only the second particle removal membrane device, the first and second particles. The same effect can be obtained if water can be switched to both of the removal membrane devices.

  The ultrapure water production and supply system of the present invention includes an ultrapure water production system of the present invention, a supply pipe for supplying ultrapure water produced by the ultrapure water production system to a water use point, and a surplus of the water use point And a return pipe for returning water to the ultrapure water production system.

  In the present invention, it is preferable that the second fine particle removing membrane apparatus can insert, blow and remove the membrane and is resistant to the cleaning solution and the sterilizing solution. Further, it is preferable that the membrane is resistant to the cleaning solution and the sterilizing solution, and the pore size of the membrane satisfies the required water quality of ultrapure water.

  The specifications of the ultraviolet device are determined by the required water quality of ultrapure water, and there is no particular limitation.

  The specifications of the particulate removal membrane device and the piping are determined by the required water quality of the ultrapure water, the cleaning solution, and the sterilizing solution, and are not particularly limited.

  As the alkaline cleaning solution, one obtained by dissolving one or more basic compounds selected from the group consisting of ammonia, ammonium compounds, alkali metal hydroxides and alkali metal oxides in ultrapure water, In particular, a solution in which a tetraalkylammonium compound is dissolved in ultrapure water is preferable. The water used for the cleaning solution or flushing is preferably desalted water, more preferably primary pure water or ultrapure water.

  As the sterilizing solution, there are few metal impurities and no corrosion occurs, in particular, an aqueous solution of pH 4 to 7 having a sterilizing action, particularly a hydrogen peroxide concentration of 0.01 to 10% by weight and a temperature of 10 to 10. Hydrogen peroxide water at 50 ° C., ozone water having an ozone concentration of 1 to 50 mg / L and a temperature of 10 to 40 ° C., warm pure water composed of primary pure water or ultrapure water having a temperature of 60 ° C. or higher is preferable. The water used for the sterilizing solution is preferably desalted, more preferably primary pure water or ultrapure water.

In addition, the pure water in this invention and an ultrapure water shall have the following water quality.
Primary pure water: resistivity 10 MΩ · cm or more
TOC 100 μg / L or less Ultrapure water: Resistivity 15 MΩ · cm or more
TOC 1μg / L or less
Metals 1ng / L or less

  As described above, the second fine particle removal membrane device, particularly the second fine particle removal capable of removing fine particles and viable bacteria during cleaning sterilization or sterilization and inserting, flushing, and removing the membrane regardless of the operation status of the system. By providing the membrane device in the ultrapure water production system, it is possible to supply ultrapure water with good water quality within a short period of time after cleaning and sterilization.

  According to the ultrapure water production system and the ultrapure water piping system of the present invention, cleaning sterilization and sterilization end even with ultrapure water that requires severe particle size reduction and / or number reduction regardless of particle size. Instead of changing the time until the required water quality is satisfied, it becomes possible to supply water use points (use points) while shortening rather.

1 is a system diagram of an ultrapure water production system and an ultrapure water production supply system according to a first embodiment. 1 is a system diagram of an ultrapure water production system and an ultrapure water production supply system according to a first embodiment. 1 is a system diagram of an ultrapure water production system and an ultrapure water production supply system according to a first embodiment. 1 is a system diagram of an ultrapure water production system and an ultrapure water production supply system according to a first embodiment. 1 is a system diagram of an ultrapure water production system and an ultrapure water production supply system according to a first embodiment. 1 is a system diagram of an ultrapure water production system and an ultrapure water production supply system according to a first embodiment. 1 is a system diagram of an ultrapure water production system and an ultrapure water production supply system according to a first embodiment. 1 is a system diagram of an ultrapure water production system and an ultrapure water production supply system according to a first embodiment. It is a systematic diagram of the ultrapure water production system and ultrapure water production supply system of a comparative example. It is a systematic diagram of the ultrapure water production system and ultrapure water production supply system of a comparative example. It is a systematic diagram of the ultrapure water production system and ultrapure water production supply system of a comparative example. It is a systematic diagram of the ultrapure water production system and ultrapure water production supply system of a comparative example. It is a systematic diagram of the ultrapure water production system and ultrapure water production supply system of a comparative example. It is a systematic diagram of the ultrapure water production system and ultrapure water production supply system of a comparative example. It is a systematic diagram of the ultrapure water production system and ultrapure water production supply system which concern on 2nd Embodiment. It is a systematic diagram of the ultrapure water production system and ultrapure water production supply system which concern on 2nd Embodiment. It is a systematic diagram of the ultrapure water production system and ultrapure water production supply system which concern on 2nd Embodiment. It is a systematic diagram of the ultrapure water production system and ultrapure water production supply system which concern on 2nd Embodiment. It is a systematic diagram of the ultrapure water production system and ultrapure water production supply system which concern on 2nd Embodiment. It is a systematic diagram of the ultrapure water production system and ultrapure water production supply system which concern on 2nd Embodiment. It is a systematic diagram of the ultrapure water production system and ultrapure water production supply system which concern on 2nd Embodiment.

  Hereinafter, the present invention will be described more specifically with reference to the drawings.

  FIG. 1 is a system diagram of an ultrapure water production system and an ultrapure water supply piping system according to a first embodiment of the present invention.

  The ultrapure water production system 1 includes a tank 11, a pump 12, a heat exchanger 13, an ultraviolet ray device (ultraviolet oxidation device) 14, an ion exchange device 15, and a first particulate removal membrane device 16. These devices are connected by piping or tubes. In some cases, a membrane separation device including a reverse osmosis (RO) membrane between the pump 12 and the first particulate removal membrane device 16, a deaeration device, an oxidant removal device, a pump different from the pump 12, and an ion exchange device 15. Different or similar ion exchange devices may be incorporated. The ultraviolet device 14 is either a low-pressure ultraviolet oxidizer or an ultraviolet sterilizer depending on the required quality of ultrapure water. The fine particle removal membrane device is composed of an ultrafiltration membrane device (UF), a microfiltration membrane device (MF), or a reverse osmosis membrane device (RO) depending on the required water quality and sterilization conditions of ultrapure water.

  In this embodiment, a bypass pipe 15 a that short-circuits the outflow pipe 14 b of the ultraviolet device 14 and the outflow pipe 15 b of the ion exchange apparatus 15 is provided so as to bypass the ion exchange apparatus 15. Although illustration is omitted, a bypass pipe may be incorporated in the heat exchanger 13 and the ultraviolet device 14.

  A bypass pipe 16a, a second particulate removal film apparatus 17, and a bypass pipe 16b are provided so as to bypass the first particulate removal film apparatus 16. A bypass pipe 17 a is provided so as to bypass the second particulate removal film device 17. A first blow pipe 16c is connected to the most downstream side of the bypass pipe 16b.

  The ultrapure water supply piping system 2 includes use points (use points) 3 of ultrapure water and flow paths (pipes or tubes) 21 and 22 of ultrapure water. A second blow pipe 22 a (FIGS. 4, 7 and 8) is provided at the most distal end portion of the flow path 22.

  A bypass pipe 2 a is provided between the pipes 21 and 22 so as to bypass the water use point 3. Although illustration is omitted, a flow path switching valve is provided at a branching part or a joining part of each pipe or tube.

  In the steady operation state, the primary pure water 4 and the ultrapure water returned from the ultrapure water supply pipe 22 are received in the tank 11 as shown in FIG. The water in the tank 11 (ultra pure water raw water) is sent by the pump 12 and processed in the heat exchanger 13, the ultraviolet ray device 14, the ion exchange device 15, and the first fine particle removal membrane device 16 in order to obtain ultra pure water. Manufactured.

  In addition, primary pure water is prepared by treating pretreated raw water with a reverse osmosis (RO) membrane device, then treating with an ion exchange device, and further treating with a reverse osmosis membrane. It can obtain by processing with a tower ion-exchange apparatus, and also processing with a reverse osmosis (RO) membrane apparatus, an ultraviolet-ray apparatus, an ion exchange apparatus, and a deaeration apparatus.

  The ultrapure water produced by the ultrapure water production system 1 is sent to the water use point 3 through the flow path 21 and part of it is used, and the unused ultrapure water passes through the flow path 22 and is ultrapure. Return to the water production system 1.

[Example of cleaning procedure]
When cleaning and sterilizing the ultrapure water production system 1 and the ultrapure water supply piping system 2, FIG. 2 → FIG. 3 → FIG. 4 → FIG. 5 → FIG. 4 → FIG. 3 → FIG. 4 → FIG. Water is passed in the order of 4 → FIG. 7 → FIG. In each figure, a pipe or tube represented by a thick solid line indicates that water is flowing, and a pipe or tube represented by a thin solid line indicates that no water is flowing.

<FIG. 2: Cleaning of Second Fine Particle Removal Film Device>
First, as shown in FIG. 2, the ultrapure water obtained from the first particulate removal membrane device 16 is supplied to the use point 3 in the same manner as in FIG. A part of the effluent water is supplied from the bypass pipe 16a to the particulate removal membrane device 17, discharged from the blow pipe 16c outside the system, and blown for a certain time. After the resistivity reaches 18 MΩ · cm or more, a film is attached to the second fine particle removal film device 17.

<Figure 3: Alkaline cleaning>
After measuring the fine particles in the blow water from the blow pipe 16c and confirming that the number of fine particles is not more than a prescribed number (for example, 500 particles / L or less of 50 nm or more), the ultrapure water production system 1 and the ultrapure water The supply piping system 2 is washed with alkali. As shown in FIG. 3, valve selection (channel switching) is performed so that water flows by bypassing the ion exchange device 15 and the first particulate removal membrane device 16 of the ultrapure water production system 1. In addition, the water level of the tank 11 is adjusted at the lowest level where the level is low and the pump does not stop. When the bypass pipes are also incorporated in the heat exchanger 13 and the ultraviolet device 14, the valves are slightly opened so that the ultrapure water or primary pure water and the cleaning sterilizing solution flow through these pipes. Further, the valve is slightly opened so that the liquid also flows through the bypass pipe 2 a of the ultrapure water supply piping system 2. The blow pipe 16c is closed.

  Thereafter, the alkaline solution is injected into the tank 11 so that the effluent from the ultrapure water production system becomes an alkaline solution having a pH of 9 or more, and the pump 12 is used to supply the ultrapure water production system 1 and the ultrapure water supply as shown in FIG. Circulate in the piping system 2. The alkali cleaning time is preferably 0.5 Hr or more, particularly about 1 to 2 Hr.

<Figure 4: Flushing>
Next, as shown in FIG. 4, the primary pure water 4 is supplied to the tank 11, and the second blow pipe 22 a branched from the most distal end of the pipe 22 (downstream side of the junction with the bypass pipe 2 a) is opened. Then, the return water is blown out of the system, and the alkaline solution in the ultrapure water production system 1 and the ultrapure water supply piping system 2 is flushed with the primary pure water 4 to the outside of the system.

<Figure 5: Sterilization cleaning>
After confirming that the pH of this flushing waste water (drain water from the blow pipe 22a) is 8 or less and / or the resistivity is 10 MΩ · cm or more, the ultrapure water production system using the sterilizing solution shown in FIG. 1 and sterilization cleaning in the ultrapure water supply piping system 2 are performed.

  As shown in FIG. 5, at the time of sterilization with the sterilization solution, the valve is selected so as to bypass the ion exchange device 15 and the particulate removal membrane device 16 of the ultrapure water production system 1 as in the case of cleaning with the alkaline solution, and the tank 11 Adjust the water level. When the bypass pipe is also incorporated in the heat exchanger 13 and the ultraviolet device 14, the line is slightly opened. Thereafter, the ultrapure water in the ultrapure water production system 1 and the ultrapure water supply piping system 2 is heated to the required temperature by the heat exchanger 13 as necessary so that the ultrapure water becomes sterilized water, and hydrogen peroxide is injected into the tank 11. The ultrapure water production system 1 and the ultrapure water supply piping system 2 are circulated using the pump 12. This sterilization cleaning is preferably performed for 0.5 hour, particularly 1 to 2 hours.

<Figure 4: Flushing>
Next, the flushing process of FIG. 4 is performed, and the sterilizing solution in the ultrapure water production system 1 and the ultrapure water supply piping system 2 is pushed out of the system with the primary pure water 4. This flushing is performed until the hydrogen peroxide concentration of the flushing water discharged from the blow pipe 22a becomes 1 mg / L or less.

<Figure 3: Second alkali cleaning>
After completion of the flushing, alkali cleaning (second alkali cleaning) is performed again as shown in FIG. This cleaning method is the same as the first alkali cleaning.

<Figure 4: Flushing>
After the second alkali cleaning, flushing is performed as shown in FIG. This flushing method is the same as the aforementioned flushing method.

<FIGS. 6 and 5: Second sterilization cleaning>
After the flushing, the second sterilization cleaning with hydrogen peroxide is performed. The first half water passing method at the time of the second sterilization washing is performed according to FIG.
The water flow method of FIG. 6 is basically the same as that of FIG. 5 except that the hydrogen peroxide-containing water from the bypass pipe 15a is not only the second fine particle removal film device 17 but also the first fine particle removal film device. 16 differs from FIG. Other water flow conditions are the same as in FIG. The sterilization cleaning in FIG. 6 is preferably performed for 0.5 Hr or more, particularly about 0.5 to 1 Hr.
After performing the sterilization cleaning shown in FIG. 6, the process proceeds to the sterilization cleaning shown in FIG.

<Figure 4: Flushing>
Next, flushing is performed by the method shown in FIG. The flushing conditions are the same as in the flushing case.

<Figure 7: Primary finish>
Next, primary finishing water flow shown in FIG. 7 is performed. This primary finishing water flow is substantially the same as the above flushing water flow, but is different from the flushing process in that the effluent water from the ultraviolet device 14 is passed not only to the bypass pipe 15a but also to the ion exchange device 15. The rest is the same as in the case of flushing.

<Secondary finish>
Subsequently, the secondary finishing water flow shown in FIG. 8 is performed. The second finishing water passage is different from the first finishing water passage in FIG. 7 in the following points (1) to (3), and the other points are the same as the first finishing water passage.
(1) The effluent from the ultraviolet oxidizer 14 is not passed through the bypass pipe 15a, but only through the ion exchanger 15.
(2) The effluent from the ion exchange device 15 is passed through both the first particle removal membrane device 16 and the second particle removal membrane device 17.
(3) The water from the particulate removal membrane devices 16 and 17 is not passed through the water use point 2, but the entire amount is circulated through the bypass pipe 2a.

  This secondary finishing water flow is performed until the quality of the outflow water from the blow pipe 22a becomes the target ultrapure water quality. After the completion of the secondary finishing water flow, the operation returns to the steady operation shown in FIG.

  15 to 20 show a second embodiment of the present invention.

  In the second embodiment shown in FIGS. 15 to 20, the second particulate removal membrane device 17 and its bypass pipe 17 a are provided in the bypass pipes 15 c and 15 d of the ion exchange device 15, and the blow pipe 16 c is a bypass pipe. The ultrapure water production system 1 and the ultrapure water supply piping system 2 have the same configuration as that shown in FIG.

  15 to 20, the pipe upstream of the second particulate removal membrane device 17 in the bypass piping of the ion exchange device 15 is denoted by reference numeral 15 c, and is more than the second particulate removal membrane device 17. Reference numeral 15d is attached to the downstream piping. The bypass pipe 17a is provided to bypass the particulate removal membrane device 17 so as to short-circuit the pipes 15c and 15d. Other reference numerals in FIGS. 15 to 20 denote the same parts as those in FIGS.

[Example of cleaning procedure]
When cleaning and sterilizing the ultrapure water production system 1 and the ultrapure water supply piping system 2, FIG. 15 → FIG. 16 → FIG. 17 → FIG. 18 → FIG. 17 → FIG. Water is passed in the order of 17 → FIG. 20 → FIG. In each figure, a pipe or tube represented by a thick solid line indicates that water is flowing, and a pipe or tube represented by a thin solid line indicates that no water is flowing.

<FIG. 15: Cleaning of Second Fine Particle Removal Film Device>
First, as shown in FIG. 15, ultrapure water obtained from the first particulate removal membrane device 16 is supplied to the use point 3 as in FIG. 2, and the excess water is returned to the tank 11, while the ultraviolet device 14 flows out. Part of the water is supplied from the bypass pipe 15c to the particulate removal membrane device 17, discharged from the blow pipe 16c to the outside of the system, and blown for a certain time. After the resistivity reaches 18 MΩ · cm or more, a film is attached to the second fine particle removal film device 17.

<Figure 16: Alkaline cleaning>
After measuring the fine particles in the blow water from the blow pipe 16c and confirming that the number of fine particles is not more than a prescribed number (for example, 500 particles / L or less of 50 nm or more), the ultrapure water production system 1 and the ultrapure water The supply piping system 2 is washed with alkali. As shown in FIG. 16, valve selection (flow path switching) is performed so that water flows by bypassing the ion exchange device 15 and the first particulate removal membrane device 16 of the ultrapure water production system 1. In addition, the water level of the tank 11 is adjusted at the lowest level where the level is low and the pump does not stop. When the bypass pipes are also incorporated in the heat exchanger 13 and the ultraviolet device 14, the valves are slightly opened so that the ultrapure water or primary pure water and the cleaning sterilizing solution flow through these pipes. Further, the valve is slightly opened so that the liquid also flows through the bypass pipe 2 a of the ultrapure water supply piping system 2. The blow pipe 16c is closed.

  Thereafter, an alkaline solution is injected into the tank 11 so that the effluent from the ultrapure water production system 1 becomes an alkaline solution having a pH of 9 or higher, and the pump 12 is used to pump the ultrapure water production system 1 and the ultrapure water as shown in FIG. Circulate in the supply piping system 2. The alkali cleaning time is preferably 0.5 Hr or more, particularly about 1 to 2 Hr.

<Figure 17: Flushing>
Next, as shown in FIG. 17, the primary pure water 4 is supplied to the tank 11, and the second blow pipe 22 a branched from the most distal end of the pipe 22 (downstream side of the junction with the bypass pipe 2 a) is opened. Then, the return water is blown out of the system, and the alkaline solution in the ultrapure water production system 1 and the ultrapure water supply piping system 2 is flushed with the primary pure water 4 to the outside of the system.

<Fig. 18: Sterilization cleaning>
After confirming that the pH of this flushing waste water (drain water from the blow pipe 22a) is 8 or less and / or the resistivity is 10 MΩ · cm or more, the ultrapure water production system using the sterilizing solution shown in FIG. 1 and sterilization cleaning in the ultrapure water supply piping system 2 are performed.

  As shown in FIG. 18, at the time of sterilization with the sterilization solution, the valve is selected so as to bypass the ion exchange device 15 and the particulate removal membrane device 16 of the ultrapure water production system 1 as in the case of cleaning with the alkaline solution, and the tank 11 Adjust the water level. When the bypass pipe is also incorporated in the heat exchanger 13 and the ultraviolet device 14, the line is slightly opened. Thereafter, the ultrapure water in the ultrapure water production system 1 and the ultrapure water supply piping system 2 is heated to the required temperature by the heat exchanger 13 as necessary so that the ultrapure water becomes sterilized water, and hydrogen peroxide is injected into the tank 11. The ultrapure water production system 1 and the ultrapure water supply piping system 2 are circulated using the pump 12. This sterilization cleaning is preferably performed for 0.5 hour, particularly 1 to 2 hours.

<Figure 17: Flushing>
Next, the flushing process of FIG. 17 is performed, and the sterilizing solution in the ultrapure water production system 1 and the ultrapure water supply piping system 2 is pushed out of the system with the primary pure water 4. This flushing is performed until the hydrogen peroxide concentration of the flushing water discharged from the blow pipe 22a becomes 1 mg / L or less.

<FIG. 16: Second alkali cleaning>
After completion of flushing, alkali cleaning (second alkali cleaning) is performed again as shown in FIG. This cleaning method is the same as the first alkali cleaning.

<Figure 17: Flushing>
After the second alkali cleaning, flushing is performed as shown in FIG. This flushing method is the same as the aforementioned flushing method.

<FIGS. 19 and 18: Second Sterilization Cleaning>
After the flushing, the second sterilization cleaning with hydrogen peroxide is performed. The first half water passing method at the time of the second sterilization cleaning is performed according to FIG.
The water flow method of FIG. 19 is basically the same as that of FIG. 18, but the hydrogen peroxide-containing water from the bypass pipe 15d is applied not only to the bypass pipes 16a and 16b but also to the first particulate removal membrane device 16. It differs from FIG. 18 in that water is passed. Other water flow conditions are the same as those in FIG. The sterilization cleaning in FIG. 19 is preferably performed for 0.5 Hr or more, particularly about 0.5 to 1 Hr.
After performing the sterilization cleaning of FIG. 19, the process proceeds to the sterilization cleaning of FIG. 18, and preferably sterilization cleaning is performed for about 1 to 24 hours, particularly about 2 to 12 hours.

<Figure 17: Flushing>
Next, flushing is performed by the method shown in FIG. The flushing conditions are the same as in the flushing case.

<Figure 20: Primary finish>
Next, primary finishing water flow shown in FIG. 20 is performed. The first finishing water flow is substantially the same as the flushing water flow, but the flushing process is performed in that the outflow water from the ultraviolet device 14 is passed not only to the fine particle removal membrane device 17 but also to the ion exchange device 15. The others are the same as in the case of flushing.

<Secondary finish>
Next, the second finishing water flow shown in FIG. 21 is performed. This second finishing water flow is different from the first finishing water flow of FIG. 20 in the following points (1) to (3), and the other points are the same as the primary finishing water flow.
(1) The effluent water from the ultraviolet oxidation device 14 is not passed through the fine particle removal membrane device 17 but only through the ion exchange device 15.
(2) The effluent from the ion exchange device 15 is passed through both the first particulate removal membrane device 16 and the bypass pipes 16a and 16b.
(3) The water from the particulate removal membrane device 16 is not passed through the use point 3, but the entire amount is circulated through the bypass pipe 2a.

  This secondary finishing water flow is performed until the quality of the outflow water from the blow pipe 22a becomes the target ultrapure water quality. After the completion of the secondary finishing water flow, the operation returns to the steady operation.

  In addition, said description is an example of this invention and is good also as cleaning procedures other than the above.

  For example, the alkali cleaning may be performed only once or three times or more. Moreover, after performing alkali washing | cleaning in multiple times on both sides of the flushing process, you may transfer to a disinfection washing | cleaning process. In the sterilization cleaning process, only the process shown in FIG. 6 may be performed. In this case, the process of FIG. 6 may be performed a plurality of times with the flushing process interposed therebetween.

  Hereinafter, the present invention will be described more specifically with reference to examples, comparative examples, and experimental examples. In addition, the following Examples 1 and 2 and Comparative Example 1 are applied to a newly installed ultrapure water production system, and Examples 3 and 4 and Comparative Example 2 are those after the steady operation of this ultrapure water production system. This is applied during maintenance.

[Example 1]
FIG. 2 → FIG. 3 → FIG. 4 → FIG. 5 → FIG. 4 → FIG. 3 → FIG. 4 → FIG. 6 → FIG. 5 → FIG. Washing was performed according to the procedure of 4 → FIG. 7 → FIG. 8 (see Table 1).

In a steady operation state, ultrapure water flows through the pipe 21 at a flow rate of 0.75 m / sec (15 m ³ / Hr).

<Preliminary cleaning>
In the flow of FIG. 2, water was passed through the pipe 21 so as to be 13 m ³ / Hr and through the blow pipe 16c to be 2 m ³ / Hr.

<First alkali cleaning>
As shown in FIG. 3, the ultrapure water production system 1 and the ultrapure water production system 1 were poured into the tank 11 by injecting an aqueous solution of tetraammonium hydroxide having a concentration of 25 mg / L to a pH of 10.5 or higher. These systems were washed by circulating an aqueous tetramethylammonium hydroxide solution between the water supply piping systems 2 for 1 hour. Water was not passed through the ion exchange device 15 and the particle removal membrane device 16, but the cleaning solution was bypassed via the bypass pipes 15 a, 16 a, 16 b and 2 a and the particle removal membrane device 17.

<Flushing>
Thereafter, in accordance with the flow of FIG. 4, the cleaning waste water is discharged from the blow pipe 22 a, the primary pure water 4 is supplied as the flushing water to the tank 11, and the flow rate 0 is supplied to the ultrapure water production system 1 and the ultrapure water supply pipe system 2. Flushing was performed by passing water at a rate of .75 m / sec to push out the cleaning solution remaining inside these systems. As shown in FIG. 4, the ion exchange device 15 and the particulate removal membrane device 16 did not pass water, and the flushing water was bypassed through the bypass pipes 15 a, 16 a, 16 b and 2 a and the particulate removal membrane device 17.

  This flushing was performed for 1 hour, and the flushing was terminated when the pH of the flushing water discharged from the blow pipe 22a reached 8.

<First sterilization cleaning>
Next, the ultrapure water production system 1 and the ultrapure water supply piping system 2 were sterilized according to the flow of FIG.

  First, it is confirmed that the lamp of the ultraviolet device 14 is turned off, and the water temperature of the ultrapure water production system 1 and the ultrapure water supply pipe system 2 circulating at a flow rate of 0.75 m / sec is changed by the heat exchanger 13. Then, hydrogen peroxide is injected into the tank 11 to a concentration of 0.1% by weight, and the hydrogen peroxide solution is circulated between the ultrapure water production system 1 and the ultrapure water supply piping system 2 for 1 hour. I let you. Again, water was not passed through the ion exchange device 15 and the particulate removal membrane device 16, but the sterilizing solution was bypassed via the bypass pipes 15 a, 16 a, 16 b and 2 a and the particulate removal membrane device 17.

<Flushing>
Thereafter, flushing was performed according to the flow of FIG. The sterilizing solution is discharged from the blow pipe 22a, the primary pure water 4 is supplied to the tank 11 as flushing water, and water is passed through the ultrapure water production system 1 and the ultrapure water supply pipe system 2 at a flow rate of 0.75 m / sec. Then, flushing was performed to push out the cleaning solution remaining inside these systems.

  This flushing was performed for 2 hours, and the flushing was terminated when hydrogen peroxide in the flushing water discharged from the blow pipe 22a was no longer detected by the hydrogen peroxide test paper.

<Second alkali cleaning>
According to the flow of FIG. 3, the alkali cleaning of the ultrapure water production system 1 and the ultrapure water supply piping system 2 was performed again.

  First, it is confirmed that the lamp of the ultraviolet device 14 is turned off, and the concentration of 25 mg / kg is applied to the tank 11 of the ultrapure water production system 1 circulating at a flow rate of 0.75 m / sec so that the pH is 10.5 or more. The tetramethylammonium hydroxide aqueous solution of L was injected, and the tetramethylammonium hydroxide aqueous solution was circulated for 2 hours between the ultrapure water production system 1 and the ultrapure water supply piping system 2 to wash these systems. Water was not passed through the ion exchange device 15 and the particle removal membrane device 16, but the cleaning solution was bypassed via the bypass pipes 15 a, 16 a, 16 b and 2 a and the particle removal membrane device 17.

<Flushing>
Thereafter, according to the flow of FIG. 4, the cleaning solution is discharged from the blow pipe 22 a, the primary pure water 4 is supplied as the flushing water to the tank 11, and the flow rate is 0 to the ultrapure water production system 1 and the ultrapure water supply pipe system 2. Flushing was performed by passing water at a rate of .75 m / sec to push out the cleaning solution remaining inside these systems.

  This flushing was performed for 1 hour, and the flushing was terminated when the pH of the flushing water discharged from the blow pipe reached 8.

<Second sterilization cleaning>
The second sterilization cleaning of the ultrapure water production system 1 and the ultrapure water supply piping system 2 was first performed according to the flow of FIG. 6, and then performed according to the flow of FIG.

  First, it is confirmed that the lamp of the ultraviolet device 14 is turned off, and the water temperature of the ultrapure water production system 1 and the ultrapure water supply pipe system 2 circulating at a flow rate of 0.75 m / sec is changed by the heat exchanger 13. Then, as shown in FIG. 6, hydrogen peroxide is injected into the tank 11 to a concentration of 0.1% by weight, and hydrogen peroxide is introduced between the ultrapure water production system 1 and the ultrapure water supply piping system 2. The solution was circulated for 2 hours. Here, the ion exchange device 15 did not pass water, and water was passed through both the fine particle removal membrane devices 16 and 17 only for the initial 30 minutes.

  Next, as shown in FIG. 5, the water flow to the fine particle removal membrane device 16 was stopped, and the sterilizing solution was circulated through the bypass pipes 15 a, 16 a, 16 b and the fine particle removal membrane device 17.

<Flushing>
Thereafter, according to the flow of FIG. 4, the cleaning solution is discharged from the blow pipe 22 a, primary pure water is supplied to the tank 11 as flushing water, and the flow rate of 0. 0 is supplied to the ultrapure water production system 1 and the ultrapure water supply pipe system 2. Flushing was performed by passing water at 75 m / sec to push out the cleaning solution remaining inside these systems.

  This flushing was performed for 2 hours, and the flushing was terminated when hydrogen peroxide in the flushing water flowing out from the blow pipe 22a was not detected by the hydrogen peroxide test paper.

<Primary finish>
Next, as shown in FIG. 7, the ion exchange device 15 and the bypass are not allowed to flow through the fine particle removal membrane device 16 but with the flushing water circulated through the bypass pipes 15 a, 16 a, 16 b and the fine particle removal membrane device 17. Water was passed through both of the pipes 15a, and the waste water was discharged from the blow pipe 22a.

<Secondary finish cleaning>
One hour after the start of the first finish cleaning, as shown in FIG. 8, the water flow to the bypass pipe 15a is stopped, and the ion exchange apparatus 15 is passed through the bypass pipes 16a and 16b and the particulate removal membrane devices 16 and 17. The treated water was passed through, and the waste water was discharged from the blow pipe 22a.

  One hour after the start of the second finish cleaning, the cleaning and sterilization of the ultrapure water production system 1 and the ultrapure water supply piping system 2 were completed. Subsequently, it returned to the steady operation shown in FIG.

  Thereafter, the number of fine particles having a diameter of 50 nm or more in ultrapure water was measured at a water use point (use point) 3 with a fine particle monitor using a light scattering method, and the relationship between the elapsed time and the number of fine particles in ultrapure water was investigated. The results are shown in Table 1.

[Comparative Example 1]
About the ultrapure water production system 1 and the ultrapure water supply piping system 2 shown in FIG. 1, FIG. 2 → FIG. 9 → FIG. 10 → FIG. 11 → FIG. 10 → FIG. 9 → FIG. The ultrapure water production system 1 and the ultrapure water supply piping system 2 were cleaned and sterilized according to the procedure of FIG. 13 to FIG. 14 (see Table 1).

  FIG. 9 shows an alkali cleaning process substantially the same as FIG. In FIG. 9, the water from the bypass pipe 15a is circulated only from the bypass pipe 16a to the bypass pipe 17a, and is not circulated to any of the fine particle removal membrane devices 16 and 17. Other conditions in FIG. 9 are the same as the alkali cleaning in FIG.

  FIG. 10 shows a flushing process similar to FIG. In FIG. 10, the flushing water from the bypass pipe 15a is not circulated through any of the particulate removal membrane devices 16 and 17, but is circulated only from the bypass pipe 16a to the bypass pipe 17a. Other conditions are the same as those of the flushing in FIG.

  FIG. 11 shows the first sterilization cleaning and the second sterilization cleaning (second half) similar to FIG. In FIG. 11, the sterilization washing water from the bypass pipe 15a is circulated only from the bypass pipe 16a to the bypass pipe 17a, and is not circulated to the first and second particulate removal membrane devices 16 and 17. Other conditions are the same as those in FIG.

FIG. 12 shows the first half flow of the second sterilization cleaning. FIG. 12 shows that the sterilized washing water from the bypass pipe 15a in FIG. (In FIG. 12, the sterilized washing water from the bypass pipe 16a is circulated to the bypass pipe 17a in FIG. 6 and is not circulated to the second particulate removal membrane device 17.)
The water flow rate to the bypass pipe 17a was 2 m ³ / Hr, and the water flow rate to the first fine particle removal membrane device 16 was 13 m ³ / Hr. Other water flow conditions in FIG. 12 are the same as those in FIG.

  FIG. 13 shows a primary finishing process similar to FIG. 7, and FIG. 14 shows a secondary finishing process similar to FIG. Both are the same as FIGS. 7 and 8 except that the water from the bypass pipe 16a is circulated through the bypass pipe 17a and is not circulated through the second particulate removal membrane device 17. The other water flow conditions in FIGS. 13 and 14 are the same as the water flow conditions in FIGS.

  The ultrapure water production system 1 and the ultrapure water supply piping system 2 were cleaned and sterilized as described above. Thereafter, the number of fine particles of φ50 nm or more in ultrapure water at the water use point (use point) 3 when steady operation is resumed is measured with a fine particle monitor using a light scattering method, and the elapsed time and the number of fine particles in ultrapure water are determined. The relationship was investigated. The results are shown in Table 1.

[Example 2]
15 to FIG. 16 to FIG. 17 to FIG. 18 to FIG. 17 to FIG. 16 to FIG. 17 to FIG. 19 to FIG. 18 to FIG. Sterilization washing was performed according to the procedure of 17 → FIG. 20 → FIG. 21 (see Table 1).

First, preliminary cleaning was performed according to the flow of FIG. The flow rate of the pipe 21 is 13 m ³ / Hr, and the flow rate of the blow pipe 16 c is 2 m ³ / Hr. Other conditions are the same as in FIG.

  FIG. 16 shows an alkali cleaning process substantially similar to FIG. In FIG. 16, the entire amount of water from the ultraviolet device 14 is circulated through the bypass pipe 15 c, the second fine particle removal film device 17, and the bypass pipes 15 d, 16 a, 16 b, and is not circulated through the first fine particle removal film device 16. ing. Other conditions in FIG. 16 are the same as the alkali cleaning in FIG.

  FIG. 17 shows a flushing process similar to that of FIG. In FIG. 17, the entire amount of water from the ultraviolet device 14 is circulated through the bypass pipe 15 c, the fine particle removal film device 17, and the bypass pipes 15 d, 16 a, and 16 b, but not through the fine particle removal film apparatus 16. Other conditions are the same as those of the flushing in FIG.

  FIG. 18 shows the first sterilization cleaning and the second sterilization cleaning (second half) as in FIG. In FIG. 18, the entire amount of water from the ultraviolet device 14 is circulated through the bypass pipe 15 c, the fine particle removal film device 17, and the bypass pipes 15 d, 16 a, and 16 b, but not through the fine particle removal film apparatus 16. Other conditions are the same as those in FIG.

  FIG. 19 shows a flow of the first half of the second sterilization cleaning. FIG. 19 shows that the sterilization washing water from the ultraviolet device 14 in FIG. 18 is not passed through the ion exchange device 15 but passed through the particulate removal membrane device 16 only for the initial 30 minutes, and the others are as shown in FIG. is there.

FIG. 20 shows a primary finishing process similar to FIG. 7, and FIG. 21 shows a secondary finishing process similar to FIG. In FIG. 20, the water from the ultraviolet device 14 is circulated through both the ion exchange device 15 and the second particulate removal membrane device 17. The combined water is circulated only through the bypass pipes 16a and 16b and is not circulated through the first particulate removal membrane device 16.
In FIG. 21, the water from the ultraviolet device 14 is circulated through the ion exchange device 15 and the first particulate removal membrane device 16, and is not circulated through the bypass pipes 15 c and 15 d and the second particulate removal membrane device 17. The other water flow conditions in FIGS. 20 and 21 are the same as the water flow conditions in FIGS.

  The ultrapure water production system 1 and the ultrapure water supply piping system 2 were cleaned and sterilized as described above. Thereafter, the number of fine particles of φ50 nm or more in ultrapure water at the water use point (use point) 3 when steady operation is resumed is measured with a fine particle monitor using a light scattering method, and the elapsed time and the number of fine particles in ultrapure water are determined. The relationship was investigated. The results are shown in Table 1.

[Example 3]
As shown in Table 1, in Example 1, the latter half of Example 1 was performed immediately after the preliminary cleaning. That is, cleaning was performed in the sequence of FIG. 2 → FIG. 6 → FIG. 5 → FIG. 4 → FIG. 7 → FIG. The conditions for each step are the same as those in Example 1. The number of fine particles of φ50 nm or more in ultrapure water at the water use point (use point) 3 after resuming steady operation is measured with a fine particle monitor using a light scattering method, and the elapsed time and the number of fine particles in ultrapure water are measured. The relationship was investigated. The results are shown in Table 1.

[Comparative Example 2]
The comparative example 2 is a simulation of the conventional example. In the comparative example 1, the latter half of the comparative example 1 is performed immediately after the preliminary cleaning. That is, as shown in Table 1, cleaning was performed in the order of FIG. 2 → FIG. 11 → FIG. 9 → FIG. 10 → FIG. The process conditions in each figure are the same as in Comparative Example 1. The number of fine particles of φ50 nm or more in ultrapure water at the water use point (use point) 3 after resuming steady operation is measured with a fine particle monitor using a light scattering method, and the elapsed time and the number of fine particles in ultrapure water are measured. The relationship was investigated. The results are shown in Table 1.

[Example 4]
In Example 2, the second sterilization washing process was performed immediately after the preliminary washing. That is, as shown in Table 1, cleaning was performed in the order of FIG. 15 → FIG. 19 → FIG. 18 → FIG. 17 → FIG. The conditions for each step are the same as in Example 2. The number of fine particles of φ50 nm or more in ultrapure water at the water use point (use point) 3 after resuming steady operation is measured with a fine particle monitor using a light scattering method, and the elapsed time and the number of fine particles in ultrapure water are measured. The relationship was investigated. The results are shown in Table 1.

  As is clear from the comparison between Example 1 and Comparative Example 1 in Table 1, the second particulate removal membrane device 17 is installed in parallel with the first particulate removal membrane device 16 as in Example 1 and water is passed through. In the ultrapure water at the water use point (use point) 3 of the ultrapure water supply piping system 2 after cleaning and sterilization of the ultrapure water production system 1 and the ultrapure water supply piping system 2 The number of fine particles of 500 / L or less could be satisfied in 3 days, which was shortened by 3 days compared with Comparative Example 1 in which the conventional method was reproduced.

  This was presumed to be because fine particles generated from the sliding portion of the pump 12 of the ultrapure water production system 1 during the cleaning and sterilization contaminated the ultrapure water supply piping system 2. Therefore, as a result of measuring the number of fine particles having a diameter of 50 nm or more at the outlet of the pump 12 of the ultra pure water production system 1 with ultra fine water production using a light scattering type fine particle monitor, about 10,000 to 20,000 particles / L are always output. It was confirmed that

  Further, the second fine particle removal membrane device 17 is installed in parallel with the ion exchange device 15 as in the second embodiment, and the water is passed therethrough, so that the ultrapure water production system 1 and the ultrapure water supply piping system 2 are cleaned and sterilized. The ultrapure water supply piping system 2 after using the water use point (use point) 3 can satisfy the number of fine particles of φ50 nm or more in the ultrapure water of 500 particles / L or less in 4 days, and the conventional method was reproduced. Compared to Comparative Example 1, it could be shortened by 2 days.

  Further, as is clear from Example 3 and Comparative Example 2 in Table 1, the ultrapure water production system can be obtained by installing the particulate removal membrane device 17 in parallel with the particulate removal membrane device 16 as in Example 3 and passing water. 1 and the number of fine particles of φ50 nm or more in ultrapure water at the water use point (use point) 3 of the ultrapure water supply piping system 2 after cleaning and sterilization of the ultrapure water supply piping system 2 500 / L The following could be satisfied in 9 hours, and 9 hours could be shortened compared with Comparative Example 1 in which the conventional method was reproduced.

  Further, the ultrapure water production system 1 and the ultrapure water supply piping system 2 were cleaned and sterilized by installing the fine particle removal membrane device 17 in parallel with the ion exchange device 15 as in Example 4 and passing water therethrough. Comparative Example 2 in which the number of fine particles of φ50 nm or more in the ultrapure water at the water use point (use point) 3 of the later ultrapure water supply piping system 2 can be satisfied in 500 hours or less in 12 hours, and the conventional method is reproduced. It was possible to shorten the time by 6 hours.

  As described above, the second fine particle removal membrane device 17 is installed in parallel with the first fine particle removal membrane device 16 or the ion exchange device 15 of the ultrapure water production system 1 or the first fine particle removal membrane device 16 and the pump. The installation time of the target particulate count in ultrapure water at the water use point (use point) 3 of the ultrapure water supply piping system 2 is greatly increased only by installing the second particulate removal membrane device between Was able to be shortened.

  Regarding the results in Table 1, when the results of the group of [Example 1, Comparative Example 1, Example 2] and the group of [Example 3, Comparative Example 2, Example 4] are compared, [Example 1, Comparative Example] The group of [1, Example 2] starts from the pre-cleaning to the second finishing, while the group of [Example 3, Comparative Example 2, Example 4] performs the second sterilization cleaning after the pre-cleaning. However, the time required for the number of fine particles having a particle diameter of 50 nm or more in ultra pure water to be 500 / L or less is short although there are few washing steps.

  As described above, [Example 1, Comparative Example 1, Example 2] is applied to a new ultrapure water production system, and [Example 3, Comparative Example 2, Example 4] This is because it is applied at the time of maintenance of the ultrapure water production system after the steady operation of the ultrapure water production system. In other words, in the newly established ultrapure water production system, a lot of fine particles are likely to come out from the piping and equipment, but for maintenance, it is applied after carrying out steady operation by performing cleaning treatment at the time of new installation. Therefore, the amount of fine particles coming out of piping and equipment is less than when it was newly established.

  The expanded ultrapure water production system, like the newly established ultrapure water production system, is likely to generate a lot of fine particles from the pipes and equipment, so the results are the same as in [Example 1, Comparative Example 1, Example 2]. Become.

  In addition, since the modified ultrapure water production system has fewer particles coming out of the pipes and equipment than the newly established or expanded ultrapure water production system, the target particle count arrival time is [Example 1, Comparative Example 1, Compared to [Example 2].

  In the above description, the configuration in which the second particulate removal membrane device is provided between the final pump of the ultrapure water production system and the first particulate removal membrane device has been described. If possible, the same effect can be obtained even if the second particle removing film device is provided in the subsequent stage of the first particle removing film device.

1 Ultrapure water production system 2 Ultrapure water supply piping system 2a Bypass piping 3 Water use point (use point)
4 Primary pure water 11 Tank 12 Pump (final pump)
13 Heat Exchanger 14 UV Device 15 Ion Exchange Device 15
16 1st particulate removal membrane device 15a, 15c, 15d, 16a, 16b Bypass piping 16c, 22a Blow piping 17 2nd particulate removal membrane device 21, 22 Flow path of ultrapure water

Claims (7)

In an ultrapure water production system comprising at least a tank, a pump, a heat exchanger, an ultraviolet device, an ion exchange device, and a first particulate removal membrane device,
An ultra-pure characterized in that a second fine particle removal membrane device is provided in parallel with the first fine particle removal membrane device or between the final pump of the ultra pure water production system and the first fine particle removal membrane device. Water production system.   In Claim 1, the 2nd particulate removal membrane device is provided in parallel with the 1st particulate removal membrane device, the passage of water only of the 1st particulate removal membrane device, the passage of water only of the 2nd particulate removal membrane device, An ultrapure water production system, characterized in that a flow path switching means for switching water flow to both the first and second particulate removal membrane devices is provided.   In Claim 2, the 1st blow piping which can discharge | emit the water which passed the 2nd particulate removal membrane apparatus out of the system before joining with the passage water of a 1st particulate removal membrane apparatus is provided. Ultrapure water production system characterized by   2. The second particulate removal membrane device according to claim 1, wherein the second particulate removal membrane device is provided in parallel with the ion exchange device, and water is passed only through the ion exchange device, water is passed through only the second particulate removal membrane device, the ion exchange device, and the second An ultrapure water production system characterized in that a flow path switching means for switching water flow to both of the fine particle removal membrane devices is provided.   5. The first blow pipe according to claim 4, wherein water that has passed through the second particulate removal membrane device can be discharged out of the system before joining with water passing through the ion exchange device. Ultra pure water production system. The ultrapure water production system according to any one of claims 1 to 5,
A supply pipe for supplying the ultrapure water produced by the ultrapure water production system to the water use point;
An ultrapure water production and supply system comprising a return pipe for returning surplus water at the water use point to the ultrapure water production system.   The ultrapure water production and supply system according to claim 6, wherein a second blow pipe branched from the return pipe is provided.

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