JPH10180254A - Method and device for producing pure water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress variation of a transmitted water quantity due to variation of water temp. by measuring a flow rate of water to be treated and controlling pressure pressurized to the water to be treated to increase or decrease the flow rate of the water to be treated, in a filtering operation performed by feeding the water to be treated to a reverse osmotic membrane device or an ultrafiltration membrane device under pressure. SOLUTION: Raw water stored in a first storage tank 1 is pressurized with a first alternate current pump 2, produced pure water via the reverse osmotic membrane device 3, a vacuum deaeration tower 6, an U.V. irradiation device 7, and an ion- exchange device 8, and then is stored in a second storage tank 9. Next, the pure water is fed to a use point 18 by second alternate current pump 3 via an U.V. irradiation device 15, an ion-exchange device 16, and an ultrafiltration device 17. At this time, a flow rate signal of a first flow rate meter 4 is fed to a first inverter control device 5 and a revolution number of the alternate current pump 2 is controlled to become a flow rate in accordance with a necessary quantity, and to become a flow rate in accordance with a use quantity at a use point 18 by a water level meter 11 at the water storage tank 9 while a revolution number of the second pump 13 is made constant.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing pure water (used herein to include ultrapure water) and a pure water producing apparatus, and more particularly to a method for producing treated water such as a reverse osmosis membrane apparatus. When producing pure water using a reverse osmosis membrane device having reduced permeation performance due to a decrease in water temperature, a method and apparatus for producing pure water capable of maintaining a predetermined amount of permeated water regardless of a change in permeation performance, Also, the present invention relates to a method and an apparatus for producing pure water in which the amount of permeated water of a filtration membrane device can be increased or decreased in accordance with a change in the amount of pure water used at a point of use.

[0002]

2. Description of the Related Art Conventionally, in a pure water production plant,
Removal of dissolved components and particulate components of the water to be treated using atmospheric degassing equipment, reverse osmosis membrane equipment, filter equipment, vacuum degassing equipment, ultraviolet irradiation organic matter decomposition equipment, ion exchange equipment, ultrafiltration membrane equipment, etc. And a specific resistance value of 18 MΩcm or more, TOC
The purity is increased to 1 ppb or less and to about several particles / cc having a particle size of 0.05 μm.

[0003] Among such apparatuses used in a pure water production plant, a reverse osmosis membrane apparatus has a property that the amount of permeated water decreases as the temperature of the water to be treated decreases. A heat exchanger is provided so that when the water temperature in winter falls, the water to be treated is heated to secure a predetermined amount of permeated water.

[0004] However, such a method has a problem in that the treatment cost is increased due to electric power for heating the water to be treated in the heat exchanger or consumed steam.

Further, in many pure water production plants, unused pure water from a point of use is returned to a water storage tank installed upstream of the ultrafiltration membrane device by a pump, and is used at the point of use. When the amount of pure water is small, the pump for supplying to the reverse osmosis membrane device is intermittently adapted to the amount of consumed water, or the primary system is circulated.

However, in such a conventional method of operating a pump, the operating power becomes excessive due to the intermittent operation of the pump, and the life of the pump itself is shortened due to the sudden rotation and sudden stop of the pump. There is a problem that pure water may be contaminated by dust generation. In addition, there is also a problem that if the time for stopping the pump becomes longer, live bacteria grow.

[0007]

As described above, in the conventional method for producing pure water and the apparatus for producing pure water, when the water temperature in winter falls, the water to be treated is heated to keep the amount of permeated water constant. There is a problem that the processing cost is increased due to the heat exchanger and the accompanying steam.

Further, since the pump is operated intermittently in accordance with the amount of pure water used at the point of use, the operating power becomes excessively large (running cost is 400 yen / m ³ in an ultrapure water production apparatus with a 70% recovery rate). Then, the power cost is 1
00 yen / m ³ , which accounts for １ ／ of the running cost. ), Sudden rotation and sudden stop of the pump shortens the life of the pump itself, and may cause contamination of pure water due to dust from the pump. There was also a problem that it would be.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and a first object of the present invention is to provide a method and an apparatus for producing pure water in which the amount of permeated water does not change due to fluctuations in water temperature. .

A second object of the present invention is to provide a method and apparatus for producing pure water capable of continuously increasing or decreasing the amount of permeated water according to the amount of water used at a point of use. Other objects of the present invention will become clear from the following description.

[0011]

In the present specification, in the primary system, the reverse osmosis membrane device is mainly used in the primary system, the water at the first stage is treated water, the second stage is treated water, and the ultrafiltration membrane device is used in the secondary system. The water at the preceding stage is treated water and the latter is treated water.

[0012] The object of the present invention is to provide a method for producing pure water including a step of supplying a water to be treated to a reverse osmosis membrane device or an ultrafiltration membrane device under pressure to perform a filtration operation. This is achieved by measuring the flow rate of the treated water and controlling the pressure for pressurizing the water to be treated so as to increase or decrease the flow rate of the treated water to an amount corresponding to the required amount.

[0013] Further, the above-mentioned object is to supply the water to be treated to a reverse osmosis membrane device under pressure and perform a filtration operation to temporarily store the primary treated water in a water storage tank. In a method for producing pure water in which a filtration operation is performed by supplying to an ultrafiltration membrane device and the obtained secondary treatment water is supplied to a point of use, (a) measuring a water level of the water storage tank;
Controlling the pressure for pressurizing the water to be supplied to the reverse osmosis membrane device so that the water level maintains a predetermined range;
(B) measuring the flow rate at the preceding stage of the use point, and based on the measured flow rate, the pressure for pressurizing the water to be supplied to the ultrafiltration membrane and the pressure for pressurizing the water to be supplied to the reverse osmosis membrane device. (C) measuring the flow rate at the stage before the use point, controlling the pressure for pressurizing the water to be supplied to the ultrafiltration membrane so that the flow rate maintains a predetermined flow rate, This is achieved by measuring the water level in the water storage tank and controlling the pressure for pressurizing the water to be treated supplied to the reverse osmosis membrane device so that the water level maintains a predetermined level.

Further, an object of the present invention is to supply the water to be treated to a reverse osmosis membrane device under pressure, perform a filtering operation, temporarily store the treated water in a water storage tank, and add the treated water. A method for producing pure water in which the secondary treatment water obtained is supplied to an ultrafiltration membrane device under pressure to perform a filtration operation, and the obtained secondary treated water is returned to the water storage tank through a point of use. (B) controlling the pressure for pressurizing the water to be treated supplied to the reverse osmosis membrane device so that the water level maintains a predetermined range; and (b) controlling the flow rate between the use point and the water storage tank. Measure and control the pressure to pressurize the water to be supplied to the ultrafiltration membrane so that the treated water to be refluxed maintains a predetermined flow rate, and measure the water level of the water storage tank, and this water level is a predetermined level. Supply to the reverse osmosis membrane device to maintain the level Controlling the pressure for pressurizing the treated water, the means for pressurizing the treated water in these inventions is a high-pressure pump such as a canned pump or a vortex pump. Are suitable.

The filtration membrane device of the present invention can be applied to any filtration membrane device whose permeation performance decreases due to a decrease in temperature. The tendency is significant and is therefore suitable for the present invention.

As the reverse osmosis membrane device, for example, various organic polymer membranes or ceramic membranes composed of cellulose acetate, aliphatic polyamide or aromatic polyamide or a composite thereof can be used. Are applicable, but are not particularly limited thereto. Further, as the type of the membrane module, a hollow fiber type module, a tubular type module, a spiral type module, or a flat membrane type module can be applied, but it is not particularly limited thereto. Examples of such a reverse osmosis membrane device include, for example, 720, 710 manufactured by Toray Industries, Inc., or
NTR-759UP, ES-10 manufactured by Nitto Denko Corporation
From low pressure (7 kgf / cm ² ) to high pressure (60 kgf / cm ² )
f / cm ² ).

In order to surely prevent precipitation of precipitates in the reverse osmosis membrane permeation apparatus and to maintain a long-term treatment capacity, the pH of the water to be treated supplied to the reverse osmosis membrane apparatus is 6 to 9 ,
Preferably, it should be 6.5 to 8.0. In order to adjust the pH of the water to be treated to be supplied to the reverse osmosis membrane device to 6 to 9, a method in which the water to be treated is passed through an anion exchange device in advance, a method of adding an alkali such as sodium hydroxide or ammonia water, Alternatively, there is a method using these methods in combination, but the method is not particularly limited thereto. The reverse osmosis membrane device may have two or more stages according to the TOC concentration of the water to be treated. For example, when the TOC concentration is 0.5 ppm to 3 ppm, it is preferable to provide a reverse osmosis membrane device in two stages.

As the flow meter used in the present invention, an area type flow meter and an impeller type flow meter can be used, but an ultrasonic type flow meter is particularly suitable because it has no moving parts and there is no water contamination. . As the water level gauge used in the present invention, an electromagnetic level switch or a float type level switch can be used, but a diaphragm type differential pressure gauge is particularly suitable.

In the present invention, a plurality of pumps may be provided. In particular, a primary treatment system using a reverse osmosis membrane device and a secondary treatment system using an ultrafiltration membrane device are connected via a water storage tank. In this system, the first pump is installed upstream of the reverse osmosis membrane device, the second pump is installed upstream of the ultrafiltration membrane device, and the reflux from the point of use is connected to the reverse osmosis membrane device. A configuration in which the water is supplied to a water tank installed between the ultrafiltration membrane devices can be adopted. When such a configuration is adopted, a first flow meter is installed downstream of the reverse osmosis membrane device, a second flow meter is installed on the reflux line from the point of use, and a water level gauge, for example, a level gauge is installed in the water storage tank. The following arbitrary operation modes can be adopted.

The flow rate is measured by a first flow meter, and the rotation speed (pressure) of the first pump is adjusted so that the flow rate becomes constant.
To keep the amount of permeated water constant.

With the rotation speed of the second pump kept constant, a second flow meter or a water level meter of a water storage tank is measured, and the rotation speed of the first pump is adjusted so that the second flow meter or the water level meter is within a certain range. Control to set the amount of permeated water according to the amount used at the use point.

The flow rate of the reflux line is measured by the second flow meter, the rotation speed of the second pump is controlled so that the flow rate is within a certain range, and the water level of the water storage tank is measured by the water level meter of the water storage tank. The number of revolutions of the first and second pumps is controlled by controlling the number of revolutions of the first pump so that the water level is within a certain range, and controlling the number of revolutions of the first and second pumps in accordance with the amount of use at the point of use. Supply pure water.

Further, when the amount of water used at the use point was large and the amount of consumed water was almost constant and stable, the water level meter installed in the water storage tank was measured without providing the reflux system having the above configuration. The number of revolutions of the first pump is controlled by the water level signal, or the number of revolutions of the second pump or the second pump and the first pump is controlled by the flow rate signal measured by the flow meter installed in front of the use point. Can be taken.

It should be noted that the present invention is not limited to such an operation mode, but can take any other operation mode as required.

The method and apparatus for producing pure water of the present invention can use many known techniques, for example, a normal-pressure degassing apparatus and a vacuum degassing apparatus used for producing pure water. It is possible to add various chemical liquid injection devices such as a gas device, an ultraviolet irradiation device, an ion exchange device, hydrogen peroxide, and an acid / alkali to the line.

[0026]

Embodiments of the present invention will be described below in detail with reference to the drawings.

[0027]

Embodiment 1 FIG. 1 is a block diagram showing a configuration of a first embodiment of the present invention.

In FIG. 1, a tank 1 stores raw water such as city water, for example, and this raw water is pressure-fed to a reverse osmosis membrane device 3 by a first AC pump 2. A first ultrasonic flow meter 4 is provided in a pipe downstream of the reverse osmosis membrane device 3. The signal output of the first ultrasonic flow meter 4 is supplied to the first inverter control device 5, and the first inverter control device 5 controls the rotation speed of the first AC pump 2 so that the flow rate is adjusted to a required amount in advance. Is controlled continuously.

The vacuum deaerator 6 uses an inert gas such as a nitrogen gas at a degree of vacuum of 35 Torr or less, based on the volume of the water to be treated, from 0.001 to 11.0, preferably from 0.1 to 1.0.
Vacuum deaeration is performed while feeding at a volume flow ratio of 01 to 0.05 to remove dissolved volatile components. The ultraviolet irradiation device 7 has 18
This is a low-pressure ultraviolet lamp for ultraviolet oxidation having a wavelength of 0 to 190 nm, and the organic substances dissolved in the water to be treated are decomposed into organic acids or carbon dioxide by the irradiation of the ultraviolet rays.

The ion exchange device 8 is, for example, a strong basic anion exchange resin Duolite A as an anion exchange resin.
-113Plus (Rohm & Haas) and strong acid cation exchange resin Duolite C- as cation exchange resin
20 (Rohm & Haas Co., Ltd.) is preferably used. A mixed bed type ion exchange apparatus in which these are preliminarily regenerated and converted into an OH type and an H type and then mixed and filled, is preferably used.

A water storage tank 9 is provided downstream of the ion exchange device 8 so as to temporarily store pure water refluxed by a second piping system 10 described later. The water tank 9 is provided with a level meter 11 for measuring the amount of pure water in the water tank 9. A second ultrasonic flow meter 12 is provided in the second piping system 10, and measures the amount of pure water to be refluxed.

A secondary pure water system is provided downstream of the water storage tank 9, and a second AC pump 13 and a second inverter control device 14 are provided downstream of the water storage tank 9. The flow rate signal from the second ultrasonic flow meter 12 provided in the second piping system 10 is supplied to the second inverter control device 14 and the second inverter control device 14 makes the flow rate according to the required amount. Thus, the rotation speed of the second AC pump 13 is controlled.

A second ultraviolet irradiation device 15 and a second ion exchange device 16 are disposed downstream of the second AC pump 13, and an ultrafiltration membrane device 17 is disposed downstream thereof. I have. As the ultrafiltration membrane device 17, a device using various polymers mainly composed of polyacrylonitrile, polyamide, polysulfone or the like as the ultrafiltration membrane can be used.

A use point 18 is arranged downstream of the ultrafiltration membrane device 17, and each of these devices is provided with a first piping system 19.
Are connected by

The unused water at the use point 17 is returned to the water storage tank 9 by the second piping system 10.

In the apparatus of the embodiment configured as described above,
The raw water once stored in the first water storage tank 1 is pressurized by a first AC pump 2 to remove ionic components and fine particle components in a reverse osmosis membrane device 3, and then a volatile component is distilled in a vacuum degassing tower 6. After being removed, the organic matter is decomposed by the ultraviolet irradiation device 7, and the organic acid component generated by the decomposition is removed by the ion exchange device 8 and is temporarily stored in the second water storage tank 9.

The pure water stored in the water storage tank 9 is passed through an ultraviolet irradiation device 15, an ion exchange device 16, and an ultrafiltration membrane device 17 by a second AC pump 13 in order, and is used at a point of use 1.
The unused pure water is returned to the second storage tank via the second piping system 10.

In this embodiment, operation can be performed in the following modes.

(1) The flow rate signal of the first flow meter 4 is supplied to the first inverter control device 5 to control the rotation speed of the AC pump 2 so as to have a flow rate corresponding to the required amount.

(2) With the rotation speed of the second pump kept constant, the AC pump 2 is controlled by the second flow meter or the water level meter of the water tank so that the flow rate corresponds to the amount used at the point of use.
To control the number of revolutions.

(3) The rotation speed of the second pump is controlled by the second flow meter and the water level gauge of the water storage tank in accordance with the use at the point of use. At that time, the ultrapure water used at the use point is measured by a water level meter, and the signal is received to control the rotation speed of the first pump.

In the operation mode (1), since the flow rate in the primary pure water system is constant, there is no fluctuation in the amount of permeated water in the primary system due to a change in water temperature.

In the operation mode (2), when the flow rate in the secondary pure water system is constant, the flow rate of pure water used at the use point and the flow rate of the pure water used to return from the use point and the water volume in the water storage tank are measured. In order to make the amount of permeated water of the reverse osmosis membrane device correspond by controlling the rotation speed of the pump, circulation and intermittent operation in the primary system are not required, thereby reducing the electricity cost of the pump operation and the reverse osmosis membrane. It is possible to prevent an increase in viable bacteria, a sudden rotation of the pump, and a sudden stop due to the stoppage of the device.

Furthermore, in the operation mode (3), the secondary pump is operated corresponding to the amount used at the point of use. At that time, the amount of water in the reservoir is measured and the primary pure water reverse osmosis membrane device is operated according to the amount used at the point of use, so the power consumption of the primary and secondary pumps can be reduced. It is. Furthermore, since the primary system circle line is not required and the reverse osmosis membrane device does not operate intermittently, the life of the pump can be extended without increase in viable bacteria, rapid rotation and sudden stop of the pump.

In the mode (3), for example, an upper limit value and a lower limit value are set in the level signal from the level meter 11, and the set permeated water amount is stepwise changed each time the upper limit value is supplied to the inverter control device. And the set permeate flow rate may be increased each time the lower limit value is supplied, so that the permeate flow rates of the primary system and the secondary system can be synchronized.

Incidentally, the power consumption rate in the case of inverter control using SU-710 manufactured by Toray Industries, Inc. as a reverse osmosis membrane is smaller than that in the conventional case where the water to be treated is heated.
In the case of (1), it is almost 2/3, and when (1) and (2) are used together, it is about 1/2. FIG. 2 shows that a heat exchanger H and a steam supply source S are installed instead of using the inverter control device shown in the first embodiment in order to maintain the permeated water amount of the water to be treated in the reverse osmosis membrane device which changes with the water temperature. It is a figure showing an important section of a conventional device. An example using this apparatus is referred to as Comparative Example 1. In FIG. 2, the same components as those in FIG. 1 are denoted by the same reference numerals. The time required for the amount of permeated water of the reverse osmosis membrane device to become constant was compared using the devices of FIGS. 1 and 2. The temperature of the water to be treated is 17 ° C.
The comparison results are shown in Table 1.

[0047]

[Table 1] As can be seen from the measurement results in Table 1, when the apparatus of the present invention is used, the time required for the amount of permeated water of the reverse osmosis membrane apparatus to be constant is half the time of the conventional apparatus. Thus, it can be said that the constant flow rate is reached more quickly by using the inverter control device used in the present invention. The running cost of the device of the present invention is 70% of that of the conventional device.

[0048]

[Embodiment 2] FIG. 3 is a block diagram showing a configuration of a second embodiment of the present invention.

In FIG. 3, the same components as those in FIG. 1 are denoted by the same reference numerals.

The configuration of the second embodiment is similar to that of the second piping system 10.
The configuration is the same as that of the first embodiment except that the second flowmeter 12 is installed before the use point without the above.

In the thus configured apparatus of the second embodiment, the raw water once stored in the first water storage tank 1 is pressurized by the first AC pump 2 as in the first embodiment. is ion component and particulate component by the reverse osmosis unit 3 is removed, and then after the volatile components were removed in vacuum degassing tower 6, decomposing organic matter in the organic acid and CO ₂ in the first ultraviolet oxidation device 7 Then, the organic acid component and the ionic component are removed by the ion exchange device 8 and temporarily stored in the second water storage tank 9. The pure water stored in the water storage tank 9 is supplied to the use point 18 by the second AC pump 13 through the ultraviolet oxidizing device 15, the ion exchange device 16, the ultrafiltration device 17, and the flow meter 12 in this order.

In this embodiment, the operation can be performed in the following modes.

(1) The water level signal of the water level gauge 11 in the water storage tank 9 is supplied to the first inverter control device 5 to control the rotation speed of the AC pump 2 so that the flow rate follows the usage amount.

(2) The flow signal of the second flow meter 12 is
To the inverter control device 14 and the first inverter control device 5 to control the rotation speeds of the AC pumps 13 and 2 so that the flow rate is in accordance with the usage amount.

(3) The flow signal of the second flow meter 12 is
While controlling the number of revolutions of the AC pump 13 so that the flow rate of the AC pump 13 is adjusted to the flow rate according to the usage amount.
The water level signal of the water level gauge 11 in the water storage tank 9 is supplied to the first inverter control device 5 to control the rotation speed of the AC pump 2 so that the water level in the water storage tank 9 is constant.

In this embodiment, when the amount of pure water used at the point of use increases, the pressure at the stage preceding the point of use decreases and the flow rate increases. Conversely, when the amount of pure water used at the point of use decreases, the amount of pure water used decreases. The pressure increases and the flow decreases. The second ultrasonic flow meter 12 detects such an increase or decrease in the flow rate and outputs the control signal as a control signal to the second inverter control device 14.
And to the first inverter control device 5.

Also in the embodiment shown in FIG. 2, the amount of permeated water does not fluctuate due to a change in water temperature, and circulation and intermittent operation are not required. In particular, the power consumption of the pump operation is reduced as compared with the first embodiment. Can be. Further, there is also obtained an effect that the life of the pump can be extended by preventing the increase of viable bacteria due to the stoppage of the operation of the reverse osmosis membrane device, the sudden rotation of the pump, and the sudden stop.

[0058]

As is clear from the above embodiments, according to the present invention, the amount of permeated water of the filtration membrane device can be kept constant even if the water temperature is lowered in winter or the like, and it has been conventionally used. A heat exchanger for keeping the water temperature constant can be omitted.

When the amount of pure water used at the point of use fluctuates greatly, the amount of permeated water of the filtration membrane device can be increased or decreased according to the amount of use.

Further, by using an AC pump as a pump for supplying the water to be treated to the filtration membrane device and controlling the rotation speed of the AC pump by an inverter, the pressure can be changed continuously, and , The life of the pump is prolonged, and the generation of dust can be suppressed.

Further, the amount of permeated water of the filtration membrane device is made to correspond to the amount of unused pure water from the point of use, so that the operation rate of the cycle pump is reduced and power consumption can be reduced. Furthermore, there is an effect that continuous operation of the pure water apparatus is possible and propagation of viable bacteria can be prevented.

Further, when the circulation system is not used, the circle line is not accumulated and the quality of ultrapure water is increased. Therefore, the effect of further reducing the power consumption can be obtained.

That is, it is possible to obtain an effect that the control of the operation is easier and the cost can be further reduced as compared with the related art.

[Brief description of the drawings]

FIG. 1 is a device configuration diagram showing a main part of an embodiment of the present invention.

FIG. 2 is a device configuration diagram showing Comparative Example 1.

FIG. 3 is a device configuration diagram showing a main part of another embodiment of the present invention.

[Explanation of symbols]

1 ... first water tank, 2 ... first AC pump, 3 ...
Reverse osmosis membrane device, 4 ... first ultrasonic flow meter, 5 ... first
Inverter control device of 6, vacuum degassing tower, 7 first
UV irradiation device, 8 ... first ion exchange device, 9 ...
... second water tank, 10 ... second piping system, 11 ... level meter, 12 ... second ultrasonic flow meter, 13 ... second AC pump, 14 ... second inverter control Equipment, 15
... a second ultraviolet irradiation device, 16 ... an ion exchange device,
17 ... Ultrafiltration membrane device, 18 ... Use point

Continuing from the front page (72) Inventor Naomichi Yonekawa 2-9-1-8 Okada, Atsugi-shi, Kanagawa Nomura Micro Science Co., Ltd. Inventor Izumi Kojima 2-9-8 Okada, Atsugi City, Kanagawa Prefecture Nomura Micro Science Co., Ltd.

Claims (9)

[Claims] 1. A method for producing pure water, comprising the step of supplying treated water to a reverse osmosis membrane device or an ultrafiltration membrane device under pressure to perform a filtration operation, wherein the pressure of the treated water is controlled. A method for producing pure water, comprising increasing or decreasing the flow rate of treated water. 2. A method according to claim 1, wherein the water to be treated is supplied to a reverse osmosis membrane device under pressure and a primary treatment water obtained by performing a filtration operation is temporarily stored in a water storage tank. In the method for producing pure water, which is supplied to the apparatus and performs a filtration operation, so that the obtained secondary treatment water is supplied to the point of use.
A method for producing pure water, comprising: measuring a water level in the water storage tank; and controlling a pressure for pressurizing the water to be treated supplied to the reverse osmosis membrane device so that the water level maintains a predetermined range. 3. The water to be treated is supplied to a reverse osmosis membrane device under pressure and a primary treatment water obtained by performing a filtration operation is temporarily stored in a water storage tank, and the primary treatment water is subjected to ultrafiltration membrane under pressure. In the method for producing pure water, which is supplied to the apparatus and performs a filtration operation, so that the obtained secondary treatment water is supplied to the point of use.
A method for producing pure water, comprising: measuring a flow rate in a stage preceding the use point, and controlling a pressure for pressurizing water to be treated to be supplied to the reverse osmosis membrane device based on the flow rate. 4. The water to be treated is supplied to a reverse osmosis membrane device under pressure and a primary treatment water obtained by performing a filtration operation is temporarily stored in a water storage tank, and the primary treatment water is subjected to ultrafiltration membrane under pressure. In the pure water production method in which the obtained secondary treatment water is supplied to the use point by supplying it to the apparatus and performing a filtration operation, the flow rate at the stage before the use point is measured, and this flow rate becomes a predetermined flow rate. In order to maintain, while controlling the pressure to pressurized water to be supplied to the ultrafiltration membrane, measure the water level of the water storage tank, so that this water level maintains a predetermined level, the reverse osmosis membrane device A method for producing pure water, comprising controlling a pressure for pressurizing supplied water to be treated. 5. The water to be treated is supplied to a reverse osmosis membrane device under pressure, and the primary treatment water obtained by performing a filtration operation is temporarily stored in a water storage tank. The primary treatment water is subjected to ultrafiltration membrane under pressure. In a method of producing pure water in which the supplied secondary treatment water is supplied to the apparatus and subjected to a filtration operation, and the obtained secondary treatment water is returned to the water storage tank through a point of use, the water level of the water storage tank is measured, and the water level is measured. A method for producing pure water, comprising: controlling a pressure for pressurizing water to be treated supplied to the reverse osmosis membrane device so as to maintain a predetermined range. 6. The water to be treated is supplied to a reverse osmosis membrane device under pressure, and the primary treatment water obtained by performing a filtration operation is temporarily stored in a water storage tank, and the primary treatment water is subjected to ultrafiltration membrane under pressure. In the method of producing pure water in which the obtained secondary treatment water is returned to the water storage tank through the use point by performing a filtration operation by supplying to the apparatus, the flow rate between the use point and the water storage tank is measured. Controlling the pressure for pressurizing the water to be supplied to the ultrafiltration membrane, and measuring the water level of the water storage tank so that the refluxed treated water maintains a predetermined flow rate, and measures the water level to a predetermined level. A method for producing pure water, wherein a pressure for pressurizing the water to be treated supplied to the reverse osmosis membrane device is controlled so as to maintain the same. 7. A treatment water supply system, a pump for pressurizing treatment water, a reverse osmosis membrane device or an ultrafiltration membrane device, a piping system for connecting these in order, and the reverse osmosis membrane device or the ultrafiltration device. An apparatus for producing pure water, comprising: a flow meter for measuring a flow rate in a pipe downstream of a filtration membrane device; and a control device for controlling a rotation speed of the pump based on a flow signal of the flow meter. 8. A raw water supply system, a first pump for pressurizing raw water, a reverse osmosis membrane device, a first piping system for connecting these in order, and a water storage for receiving outlet water of the first piping system. And a second tank for pressurizing the treated water in the water tank as the water to be treated.
Pump, an ultrafiltration membrane device, a use point for supplying the treated water treated by the ultrafiltration membrane device, a second piping system for sequentially connecting these, and a pump disposed before the use point. Pure water, comprising: a flow meter, and a control device that controls the rotation speed of the second pump or the second pump and the first pump in accordance with the flow rate measured by the flow meter. Manufacturing equipment. 9. A raw water supply system, a first pump for pressurizing raw water, a reverse osmosis membrane device, a first piping system for connecting these in order, and a water storage for receiving outlet water of the first piping system. And a second tank for pressurizing the treated water in the water tank as the water to be treated.
Pump, an ultrafiltration membrane device, a use point for supplying treated water treated by the ultrafiltration membrane device, a second piping system for connecting these in order, and an outlet water of the second piping system. A third pipe system that guides the water to the water tank, a water level meter provided in the water tank, a flow meter installed in the third pipe system, and a water level of the water tank measured by the water level meter. Pure water, comprising: a control device that controls the rotation speed of the first pump in accordance with the flow rate; and a control device that controls the rotation speed of the second pump in accordance with the flow rate measured by the flow meter. Manufacturing equipment.