JP5300023B2 - Pure water production apparatus and pure water production method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and a method for producing pure water, in each of which by removing a scale component from concentrated water, the amount of the concentrated water to be discharged or the exchange frequency of equipment can be reduced, and furthermore, a trouble due to the adhesion of scale to the apparatus can be prevented, while the labor hour and cost required for the maintenance can be reduced. <P>SOLUTION: The apparatus for producing pure water includes: a supply means having a supply route for supplying supply water; a concentration membrane means for filtering the supply water to obtain pure water and concentrated water; a pure water means which is connected to the concentration membrane means to receive the supply of the pure water; and a water quality improvement means which is connected to the concentration membrane means to receive the supply of the concentrated water, includes a cathode and an anode to electrolyze the concentrated water, thereby improving the water quality of the concentrated water, and is connected to the supply route to supply the concentrated water, which is improved in the water quality, to the concentration membrane means. The cathode of the water quality improvement means is provided with a thermally-sprayed coating film, which is composed of a material including a metallic material and fluorinated pitch, on the surface thereof. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a pure water production apparatus and a pure water production method for producing pure water from water containing impurities.

  An apparatus for obtaining pure water by filtering supplied water and removing impurities such as electrolytes, solids, colloids and microorganisms in the water has been developed. The pure water obtained in this way is used for compounding and cleaning applications in the fields of medicine, industry, food, etc., and further used for purifying high-purity water excluding impurities.

  In particular, many devices have been developed that perform ultrafiltration using a reverse osmosis membrane as filtration to obtain RO water as pure water. According to ultrafiltration using a reverse osmosis membrane, pure water from which impurities are removed and concentrated water from which impurities are concentrated are obtained with the reverse osmosis membrane interposed therebetween. However, if such ultrafiltration is continued, impurities contained in the concentrated water are further concentrated. In particular, since water contains a scale component mainly composed of calcium, silica, etc. as an electrolyte, the difference in osmotic pressure increases with the increase in concentration, so that high water pressure is required for ultrafiltration. Become. As a result, the reverse osmosis membrane may be clogged or the reverse osmosis membrane may be damaged by water pressure.

  In Patent Document 1, pure water is prepared so as to prevent clogging of a reverse osmosis membrane or damage due to water pressure by discharging a part of the concentrated water outside the system while adjusting the concentrated water so as not to exceed a certain water pressure. A manufacturing apparatus is disclosed.

  Patent Document 2 discloses an apparatus for producing aseptic water provided with an ultrafiltration membrane module, and this production apparatus removes a part of the electrolyte from raw water (supply water) supplied to the ultrafiltration membrane module. It has an ion exchanger.

JP 11-104639 A Japanese Utility Model Publication No. 07-19596

  However, according to the technique of Patent Document 1, a large amount of concentrated water containing a high-concentration scale component is generated. Therefore, in order to drain this concentrated water, a large amount of water needs to be discarded. Furthermore, it is necessary to replenish the purified water production apparatus with water that has been disposed of. For this reason, the cost of water to be discarded and replenished becomes enormous and affects the environment. In addition, as the concentration of the scale component contained in the concentrated water increases, the pressure applied to the reverse osmosis membrane increases, so to prevent clogging and breakage of this reverse osmosis membrane, the concentrated water with a higher concentration is discarded, Work to replenish water is frequently required.

  By applying the technique of Patent Document 2 and providing an ion exchanger that removes the electrolyte from the raw water, it is possible to reduce the scale components contained in the concentrated water, thereby reducing the burden on the reverse osmosis membrane. Therefore, it is considered possible to reduce the amount of concentrated water discharged. However, in this case, since a large amount of scale components are adsorbed on the ion exchanger, frequent maintenance is required. Moreover, since such an ion exchanger is very expensive, the production cost of the pure water production apparatus as a whole is also greatly increased.

  In view of such circumstances, the inventors of the present application, as a method for efficiently removing the scale component from the concentrated water, passed the concentrated water through an electrolyzer and electrolyzed it, thereby removing the scale component in water from the electrode. A method for improving the water quality was developed (which is not known at the time of filing this application).

  The present invention is to produce pure water using such a water quality improvement method, and its purpose is to remove the scale component from the concentrated water to supply the supply water, discard the concentrated water, and An object of the present invention is to provide a pure water production apparatus and a pure water production method capable of reducing the replacement frequency.

  Another object of the present invention is to provide a pure water production apparatus and a pure water production method capable of preventing troubles due to the scale adhering to the apparatus and reducing maintenance labor and cost.

  The pure water production apparatus of the present invention is connected to a supply means having a supply path for supplying supply water, a concentration membrane means for filtering the supply water to obtain pure water and concentrated water, and a concentration membrane means. Pure water means that receives supply of pure water, and supply of concentrated water that is connected to the concentration membrane means, and is provided with a cathode and an anode to improve the water quality by electrolyzing the concentrated water and supply the concentrated water with improved water quality to the supply path Water quality improving means connected to the concentrated membrane means and the cathode of the water quality improving means is provided with a sprayed coating made of a material containing a metal material and a fluoride pitch on the surface.

  Concentrated water with improved water quality has a reduced ionic strength, so it is easy to concentrate in the concentration membrane means, and this is re-concentrated with the feed water. To reduce. Therefore, the cost of producing pure water can be reduced, and the influence on the environment can be reduced. By concentrating water with reduced ionic strength, pure water with high purity can be obtained and used from pure water means. Also, in the water quality improvement means, when the concentrated water is electrolyzed between the cathode and the anode, calcium and silica ions, which are the main components of the scale in the concentrated water, are attracted to the cathode and deposited on the cathode surface. The water quality of the concentrated water is improved. The cathode of the water quality improving means is in a state in which the substance is hard to adhere firmly to the surface due to the fluoride pitch contained in the sprayed coating. The scale is held on the cathode in a state where only a part of the lump-like molecules are fixed to the cathode and easily peeled off, and is not released into water. For this reason, the concentration of scale components in the concentrated water with improved water quality is reduced, and the scale is not released into the concentrated water, so there is no need to frequently discard a large amount of concentrated water, and the maintenance of the equipment can be kept to a minimum. it can. In addition, the scale held on the cathode can be easily removed by water pressure by brushing or brushing. As a result, maintenance labor and costs can be reduced, and the frequency of equipment replacement can be reduced.

  It is preferable that the surface of the thermal spray coating has irregularities formed by projecting a fluoride pitch of 1 to 100 μm from this surface. The protrusion of the fluorinated pitch increases the surface area of the fluorine element exposed on the surface of the thermal spray coating, and the area of both the metal material and the fluorine element increases. Since the pitch has water repellency, it is easy to peel off. Moreover, since there are many unevenness | corrugations, the lump of the scale which the scale contacts easily and grows easily is easy to grow.

  It is also preferable that the diameter of the fluoride pitch of the cathode is 30 to 150 μm. Within this range, the area between the metal surface and the surface of the fluorine element and the surface roughness are sufficiently secured, and the fluorinated pitch does not protrude too much from the sprayed coating and is difficult to fall off.

  More preferably, pressure control means for detecting the water pressure of the feed water and controlling the pressure of the pressurizing means is further provided. By increasing the water pressure of the supply water supplied to the concentration membrane means, the concentration membrane means can perform ultrafiltration. Furthermore, by adjusting the pressure according to the water pressure, the burden on the concentration membrane means can be reduced, and the efficiency of obtaining pure water and the purity of pure water can be kept optimal.

  It is also preferable to further include electrolysis control means for detecting the ionic strength of the concentrated water and controlling electrolysis of the water quality improvement means. It is possible to reduce the ions contained in the concentrated water by energizing the concentrated water with increased ionic strength and precipitating the scale on the cathode, or by increasing the power applied to deposit more scale on the cathode. it can.

  The pure water means further includes a pure water storage means for storing pure water, and the pure water storage means preferably further includes a water quality detection means. The obtained pure water can be stored, and the strength of the electric power supplied by the concentration membrane means and the water quality improvement means can be adjusted according to the quality of the pure water, so that it is possible to obtain pure water of the desired water quality. it can.

  It is also preferable to further include a flow rate control unit that controls the flow rate of supplying the concentrated water to the water quality improvement unit. By controlling the flow rate of concentrated water, it is possible to control the time for the scale components contained in the concentrated water to contact the cathode, to control the amount of scale deposited on the cathode, and to control the thickness and size of the scale. It can be easily removed.

  The method for producing pure water of the present invention comprises the steps of obtaining concentrated water by a reverse osmosis membrane and the above-mentioned concentration by electrolytic treatment using a cathode having a thermal spray coating on the surface made of a material containing a metal material and a fluoride pitch. A step of improving water quality, and a step of supplying purified water having improved water quality and supply water to a reverse osmosis membrane and performing ultrafiltration to obtain pure water and the above-described concentrated water.

  Concentrated water with improved water quality has a reduced ionic strength, so it is easy to concentrate in the reverse osmosis membrane, and it is reconcentrated with the feed water, so both the amount of concentrated water discarded and the amount of feed water supplied are both To reduce. Therefore, the cost of producing pure water can be reduced, and the influence on the environment can be reduced. In addition, when improving the water quality, if the concentrated water is electrolytically treated, calcium and silica ions, which are the main components of the scale in the concentrated water, are attracted to the cathode and deposited on the cathode surface, so the quality of the concentrated water is improved. To do. This cathode is in a state where it is difficult for the substance to adhere firmly to the surface due to the fluoride pitch contained in the sprayed coating. The scale is held on the cathode in a state where only a part of the lump-like molecules are fixed to the cathode and easily peeled off, and is not released into water. For this reason, the concentration of scale components in the concentrated water with improved water quality is reduced, and the scale is not released into the concentrated water, so there is no need to frequently discard a large amount of concentrated water, and the maintenance of the equipment can be kept to a minimum. it can. In addition, the scale held on the cathode can be easily removed by water pressure by brushing or brushing. As a result, maintenance labor and costs can be reduced, and the frequency of equipment replacement can be reduced. By using a reverse dialysis membrane for ultrafiltration, a large amount of feed water can be concentrated with a simple configuration, and pure water and concentrated water can be obtained.

  A step of detecting the ionic strength and water pressure of the concentrated water, and a step of decreasing the pressure applied to the reverse osmosis membrane according to the detected increase in the ionic strength and water pressure or increasing the power applied in the electrolytic treatment. It is preferable. By reducing the applied pressure according to the water pressure and increasing the electric power applied when the ionic strength of the concentrated water increases, the burden due to the water pressure on the reverse osmosis membrane is reduced, and more scale is deposited on the cathode. The ions contained in the concentrated water can be reduced, and the efficiency of obtaining pure water and the purity of pure water can be kept optimal.

  According to the present invention, since the ionic strength of the concentrated water with improved water quality is reduced, it is easy to concentrate in the concentration membrane means, and this is reconcentrated together with the supply water. Both supply amounts are reduced. Therefore, the cost of producing pure water can be reduced, and the influence on the environment can be reduced. By concentrating water with reduced ionic strength, pure water with high purity can be obtained and used from pure water means. Also, in the water quality improvement means, when the concentrated water is electrolyzed between the cathode and the anode, calcium and silica ions, which are the main components of the scale in the concentrated water, are attracted to the cathode and deposited on the cathode surface. The water quality of the concentrated water is improved. The cathode of the water quality improving means is in a state in which the substance is hard to adhere firmly to the surface due to the fluoride pitch contained in the sprayed coating. The scale is held on the cathode in a state where only a part of the lump-like molecules are fixed to the cathode and easily peeled off, and is not released into water. For this reason, the concentration of scale components in the concentrated water with improved water quality is reduced, and the scale is not released into the concentrated water, so there is no need to frequently discard a large amount of concentrated water, and the maintenance of the equipment can be kept to a minimum. it can. In addition, the scale held on the cathode can be easily removed by water pressure by brushing or brushing. As a result, maintenance labor and costs can be reduced, and the frequency of equipment replacement can be reduced.

It is a figure which shows roughly the structure of the pure water manufacturing apparatus which concerns on one Embodiment of this invention. It is the perspective view explaining the operation | movement at the time of supplying with electricity to the cathode and anode of the water quality improvement means in the pure water manufacturing apparatus of FIG. 1, and sectional drawing which expanded the part.

  Hereinafter, an embodiment of a pure water production apparatus of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the pure water production apparatus 1 is connected to a reverse osmosis membrane means (an example of the concentrated membrane means of the present invention) 3 to which supply water 20 is supplied from a supply means 2 and to the reverse osmosis membrane means 3. The water quality improvement means 4 was provided.

  The supply means 2 is connected to the reverse osmosis membrane means 3 via the supply path 5a, the reverse osmosis membrane means 3 is connected to the water quality improvement means 4 via the pipe 5b, and the water quality improvement means 4 is connected to the pipe 5c and the supply path 5a. And is connected to the reverse osmosis membrane means 3. The reverse osmosis membrane means 3 is further connected to the pure water storage means 7 through a pipe 5d. The supply water 20 from the supply means 2 and the concentrated water whose water quality has been improved by the water quality improvement means 4, that is, the treated water 41, are supplied to the reverse osmosis membrane means 3. In that case, these supply water 20 and to-be-processed water 41 are pressurized and applied by the pressurization means 6 provided in the middle of the supply path 5a, for example by a high pressure pump. The concentrated water 34 obtained from the reverse osmosis membrane means 3 is sent to the water quality improvement means 4, and the pure water 33 is sent via the pure water storage means 7 to a use point 70 that is a pure water means that receives the supply of pure water. .

  The supply means 2 is means for supplying the supply water 20 supplied to the reverse osmosis membrane means 3. The feed water 20 is desirably water having a purity comparable to that of tap water or water having a slightly higher purity, and water purified to some extent such as deionized water can also be used. In this embodiment, the supply means 2 is connected to the water supply which supplies tap water. The supply means 2 is provided with a valve 22 capable of controlling the supply amount of water, and this valve 22 is an electromagnetic valve whose opening and closing is controlled by a control device (not shown). Further, the supply means 2 is provided with a check valve 23 for preventing backflow. Between the supply means 2 and the reverse osmosis membrane means 3, a filter 21 provided with a filter or the like for removing solids contained in the supplied water is provided.

  The reverse osmosis membrane means 3 is an apparatus that generates pure water 33 and concentrated water 34 by ultrafiltration of the pressurized supply water 20 and the water to be treated 41 through a reverse osmosis membrane. The reverse osmosis membrane means 3 includes two compartments, a pure water side compartment 31 and a concentrated water side compartment 32 with a reverse osmosis membrane interposed therebetween, and performs ultrafiltration to increase the water pressure of the concentrated water side compartment 32. Pure water 33 is obtained in the pure water side section 31 and concentrated water 34 is obtained in the concentrated water side section 32. As the reverse osmosis membrane means 3, those used in the production of pure water (RO water) using a conventional reverse osmosis membrane can be used. The reverse osmosis membrane means 3 of the present embodiment uses a spiral shape of two semipermeable reverse osmosis membranes made of cellulose. When the supply water 20 is tap water or the like and contains chlorine, hypochlorous acid is generated by electrolysis of the water quality improving means 4, but the reverse osmosis membrane of cellulose is particularly desirable because it does not react with hypochlorous acid.

  In the middle of the supply path 5a connected to the concentrated water side section 32 of the reverse osmosis membrane means 3, an ionic strength sensor 60 and a water pressure sensor 61 described later are provided in addition to the pressurizing means 6 described above. On the other hand, in the middle of the pipe 5d connected to the pure water side section 31 of the reverse osmosis membrane means 3, a water quality detection sensor 71 (corresponding to the water quality detection means of the present invention) described later is provided. A manual valve 35 is provided in the middle of the pipe 5b connected from the concentrated water side section 32 of the reverse osmosis membrane means 3 to the water quality improvement means 4. Note that the flow rate of the concentrated water 34 supplied to the water quality improvement unit 4 can be controlled by the pressurizing unit 6 and the manual valve 35 described above, and these also serve as the flow rate control unit of the present invention.

  The water quality improvement means 4 is provided in the treatment tank 40, the treatment tank 40, a cathode 42 having a thermal spray coating 42a (FIG. 2) made of a material containing a metal material and a fluorinated pitch, and a treatment tank. 40, an anode 43 provided in 40, and a power source 44 for supplying a current flowing between the cathode 42 and the anode 43 are provided.

  As shown in FIG. 2, the cathode 42 is provided in the processing tank 40 so as to face the anode 43 in parallel. The entire front and back surfaces of the cathode 42 are covered with a sprayed coating 42a. The thermal spray coating 42a is made of a material including a metal material 42b and a fluoride pitch 42c.

  In the present embodiment, the main body 42d of the cathode 42 is made of SUS304, and is formed of a rectangular flat plate having dimensions of 195 mm × 240 mm in length and breadth and a thickness of 3 to 30 mm. A sprayed coating 42a is laminated on both surfaces of the electrode body 42d. An electrode terminal portion 42 e is formed at one end of the cathode 42, and the other end of a conducting wire 45 having one end connected to the power supply 44 is connected to the electrode terminal portion 42 e.

  As can be seen from the enlarged view of FIG. 2, the sprayed coating 42a has a configuration in which the fluorinated pitch 42c is dispersed in the coating formed of the metal material 42b. The thermal spray coating 42a is a coating (Japanese Industrial Standard JIS H8200) formed by heating a thermal spray material using combustion or electric energy and spraying particles that have been melted or brought close to it onto a substrate. Thus, the surface of the film is made of the metal of the metal material 42b and the fluorinated element by taking the form in which the fluoride pitch 42c is dispersed in the metal material 42b. A part of the metal material 42b may react with a part of the fluorinated pitch 42c decomposed during the thermal spraying process to be fluorinated. Here, the metal material 42b is nickel (Ni), copper (Cu), zinc (Zn), lead (Pb), cadmium (Cd), iron (Fe), chromium (Cr), or the like having high conductivity, In this embodiment, Ni is used.

  The fluoride pitch 42c is a substance obtained by fluorinating a carbon pitch. The carbon pitch is mainly composed of a structure in which aromatic condensed six-membered ring planes are laminated by cross-linking of aliphatic hydrocarbons, and is a petroleum-based carbon pitch generated as a by-product of the gas production process. This carbon pitch is directly reacted in a fluorine gas atmosphere to obtain a fluorinated pitch 42c. A preferred composition of the fluorinated pitch 42c is one having an element ratio of fluorine to carbon of about 0.5 to 1.8. Most of the fluorinated pitches 42c thus obtained have a powdery shape, that is, a fine granular shape. The diameter of the fluorinated pitch 42c is 10 to 200 μm, and the specific gravity is 2.0. When the diameter of the fluorinated pitch 42c exceeds 200 μm, or when the content exceeds 30%, the fluorinated pitch 42c easily falls off from the sprayed coating 42a.

  Since the thermal spray coating 42a is formed by the fluorinated pitch 42c and the metal material 42b, the thermal spray coating 42a has a metal surface on which scales are likely to grow and a fluorine element surface on which scales are easily peeled off. These metal surfaces and fluorine element surfaces each have a certain area, and are distributed in an uneven state with a spacing of several μm to several tens of μm (approximately 1 to 200 μm), so-called mottled distribution. It has become. Furthermore, since the granular fluoride pitch 42c protrudes from the surface of the smooth metal material 42b, the surface is formed rough. In particular, when the diameter of the fluorinated pitch 42c is 30 μm or more, the area between the metal surface and the surface of the fluorine element and the surface roughness are sufficiently secured, and the scale is more easily peeled off. Further, from the relationship with the thickness of the thermal spray coating 42a, the diameter of the fluorinated pitch 42c is desirably less than 150 μm. Furthermore, since the scale component and the surface are likely to come into contact with each other due to the irregularities on the surface of the thermal spray coating 42a, the scale is easily peeled off.

  The content of the fluorinated pitch 42c with respect to the sprayed coating 42a is preferably 1 to 30% by weight, and in this embodiment, it is about 15% by weight. Considering the stability of the fluorinated pitch 42c, the thickness of the sprayed coating 42a is more preferably 20 to 100 μm. When configured with such a diameter and content of the fluorinated pitch 42c, the ratio of the fluorinated pitch 42c and the fluorine element due to the fluorinated metal element to the surface area of the sprayed coating 42a is 0.001 to 0. .2%.

  It is desirable that the fluorinated pitch 42c protrudes from the surface of the sprayed coating 42a by about 1 to 100 μm, and that the surface of the sprayed coating 42a is uneven. The fluorinated pitch 42c may be peeled off from the thermal spray coating 42a if it protrudes too much, but it is preferable that the fluorinated pitch 42c protrude in the range of 10 to 50 [mu] m because it should have a larger surface area.

  In this embodiment, the thermal spray coating 42a is formed by a hot wire (wire gas) thermal spraying method using a thermal spray material manufactured from powdered Ni and fluoride pitch 42c. Instead of such a thermal spray material, a wire-like thermal spray material in which a fluoride pitch 42c is integrally included in a molded body having a shape suitable for thermal spraying such as a wire shape, a coil shape or a rod shape made of a metal material 42b. The sprayed coating 42a may be formed using In addition to the hot wire spraying method, a general spraying method such as a flame spraying method, a gas spraying method, an arc spraying method, a plasma spraying method or an explosion spraying method can also be used for forming the sprayed coating 42a. By the thermal spraying method, the fluorinated pitch 42c having a large diameter of 20 μm or more or 30 μm or more can be dispersed in the metal material 42b. In the thermal spraying method, the metal material that is melted during the thermal spraying into a plasma form is cooled in the air and adheres to the thermal spray target, thereby forming the thermal spray coating 42a. It is possible to control the state of the surface. Therefore, it is possible to form the surface of the thermal spray coating 42a in a state having not only a smooth surface but also irregularities.

  The connecting portion between the cathode 42 and the electrode terminal portion 42e and the exposed portion of the conductive wire 45 of the electrode terminal portion 42e are protected by a covering member 42f so as to be prevented from rusting due to the concentrated water 34 and damage due to electrolysis. In the present embodiment, the covering member 42f is formed of a caulking material made of an epoxy resin.

The anode 43 is disposed in the processing tank 40 so as to face the cathode 42 in parallel with a distance L. The distance L is, for example, 50 mm. If the distance L is too small, the scales grown on the electrodes may come into contact with each other and an accident such as a short circuit may occur. For example, in the case of a surface area such as the electrode of this embodiment, it is not desirable to be less than 25 mm. Further, when the distance L is increased, the electrical resistance between the two electrodes is increased and the efficiency of electrolysis is lowered, so that it is not particularly desirable to exceed 100 mm. In the present embodiment, the anode 43 is a DSE that is a porous electrode in which a noble metal oxide mainly composed of ruthenium oxide (RuO ₂ ) / titanium oxide (TiO) is supported on a titanium substrate as a material having high durability and high power efficiency. (Registered trademark, manufactured by Permerek Electrode Co., Ltd.) An electrode is used. However, the anode 43 may have the same configuration as the cathode 42 or other arbitrary electrode configuration. As with the cathode 42, the anode 43 includes an electrode terminal portion 43e connected to the power source 44 and a covering member 43f for protecting the electrode terminal portion 43e.

  The treatment tank 40 is filled with the concentrated water 34 from the reverse osmosis membrane means 3. The treatment tank 40 is configured so that the concentrated water 34 can be appropriately circulated through the pipe 5c and the supply path 5a, the reverse osmosis membrane means 3 and the pipe 5b. The treatment tank 40 is provided with a drain pipe 46 that can appropriately drain the concentrated water 34 together with a valve 49 that can be opened and closed. The valve 49 is an electromagnetic valve whose opening and closing is controlled by a control device (not shown).

  The power supply 44 is connected to the cathode 42 and the anode 43 through electrode terminal portions 42e and 43e and a conducting wire 45, respectively. In the present embodiment, a 1 ampere DC stabilized power supply is used as the power supply 44.

  As described above, in the supply path 5a between the pressurizing means 6 and the reverse osmosis membrane means 3, the ion strength sensor 60 for detecting the ionic strength of the supply water 20 and the water to be treated 41, the supply water 20 and the target water. A water pressure sensor 61 that detects the water pressure of the treated water 41 is provided. The ionic strength sensor 60 and the water pressure sensor 61 are connected to a control device (not shown) provided with an electronic circuit capable of controlling the operation of the pressurizing means 6, and the water pressure sensor 61 and the electronic circuit are pressurized. The pressure control means for controlling the pressure by means 6 is configured.

  The pure water storage means 7 is a storage tank for storing the pure water 33 obtained by the reverse osmosis membrane means 3 until use, and the capacity of the storage tank is determined according to the usage amount of the pure water 33. It is done. The pure water storage means 7 is connected to a use point 70 which is a means for supplying pure water 33 to the outside. Further, the pure water storage means 7 is provided with a water quality detection sensor 71 for detecting the ionic strength of the pure water 33. In the present embodiment, the water quality detection sensor 71 is provided in the middle of the pipe 5d connecting the pure water storage means 7 and the pure water side section 31, and is a sensor capable of measuring the ionic strength of the pure water 33. The use point 70 is provided with a valve 72 that can be opened and closed. The valve 72 is an electromagnetic valve whose opening and closing is controlled by a control device (not shown).

  Next, operation | movement and effect of the pure water manufacturing apparatus 1 of this embodiment are demonstrated.

  Supply water 20 supplied from the supply means 2 and treated water 41 to be described later are pressurized and supplied to the reverse osmosis membrane means 3. In the reverse osmosis membrane means 3, the feed water 20 and the water to be treated 41 are ultrafiltered by a reverse osmosis membrane, and pure water 33 from which impurities such as scale components are removed is obtained in the pure water side section 31, and concentrated. Concentrated water 34 in which impurities are concentrated in the water side compartment 32 is obtained. The concentrated water 34 is supplied to the water quality improving means 4 through the pipe 5b, subjected to electrolytic treatment, and returned to the reverse osmosis membrane means 3 again as treated water 41 which is concentrated water whose water quality has been improved. The pure water 33 is sent to the pure water storage means 7 through the pipe 5d.

  The water quality improvement process in the water quality improvement means 4 will be described below.

  In this water quality improvement means 4, by subjecting the concentrated water 34 in the treatment tank 40 to electrolytic treatment, scaled water 47 a, 47 b and 47 c contained in the concentrated water 34 are deposited to obtain treated water 41 with improved water quality. Yes. As shown in FIG. 2, the sprayed coating 42 a of the cathode 42 has a large contact angle with water due to the fact that a part of the surface is occupied by fluorine pitch 42 c and fluorine derived from the fluorinated metal material 42 b. It is difficult for liquids to come into contact with it. In the sprayed coating 42a of the water quality improvement means 4 in the present embodiment, the contact angle with water is 120 to 140 ° depending on the diameter and content of the fluorinated pitch 42c, and has high water repellency.

  In order to perform the electrolytic treatment, first, electricity is applied between the cathode 42 and the anode 43. That is, since the electrical resistance changes depending on the conditions of the scales 47 a, 47 b and 47 c held in the cathode 42 and ions in the concentrated water 34, a constant current is passed from the power source 44 between the cathode 42 and the anode 43. In the example shown in FIG. 2, a constant current of 1 ampere is supplied. When energization is performed, the scale component 48 contained in the concentrated water 34 is electrophoresed from the anode 43 side toward the cathode 42. As a result, the scale component 48 is precipitated as a solid, and is formed on the front and back surfaces of the cathode 42 as solid scales 47a, 47b and 47c. The solid scales 47a, 47b, and 47c that have already become solid grow as the scale component 48 is further retained. A large amount of solid scales 47a and 47b grow on the surface (surface) of the cathode 42 facing the anode 43. A solid scale 47c grows on the back surface of the cathode 42, although the amount is smaller than that on the front surface.

  In the sprayed coating 42a, in other words, the surface of the fluorinated pitch 42c distributed in a mottled pattern is highly water-repellent due to the presence of elemental fluorine, and the liquid remains in contact. It has become difficult. That is, even when the surface of the fluorinated pitch 42c is in contact with the concentrated water 34 in the treatment tank 40, it is difficult to keep the surface in contact with the molecules of the concentrated water 34. On the other hand, the surface of the metal material 42b, which is also distributed in an uneven state, is a contact surface 42g that can maintain a state in contact with the molecules of the concentrated water 34. Accordingly, the deposited scale is held and grows only on the contact surface 42g which is a part of the surface of the sprayed coating 42a. Therefore, as shown in FIG. 2, small solid scales 47a and 47c grown in a state where only a small part of the contact surface 42g of the thermal spray coating 42a is grown, or a part of the scale is grown in a film shape. However, the solid scale 47b or the like that maintains the contact state with the thermal spray coating 42a grows. As described above, since the massive solid scales 47a, 47b and 47c are easily separated from the cathode 42, the scale components contained in the concentrated water 34 are removed, and the solid scale may be liberated. Absent.

  As described above, the water to be treated 41, which is the concentrated water whose water quality has been improved by the water quality improving means 4, is supplied to the pressurizing means 6 together with the supply water 20, and the reverse osmosis membrane means while being pressurized by the pressurizing means 6. 3 is supplied again. The supply water 20 is supplied from the supply means 2 to the reverse osmosis membrane means 3 after impurities such as solid matter are removed by the filter 21.

  The pure water 33 obtained in the pure water side section 31 of the reverse osmosis membrane means 3 is stored in the pure water storage means 7 and is used from the use point 70 by opening the valve 72 when used. However, if the water quality of the pure water 33 detected by the water quality detection sensor 71 is unsuitable for use, it is collected from the use point 70 and discarded.

  The ionic strength and water pressure of the supply water 20 and the water to be treated 41 supplied to the reverse osmosis membrane means 3 are detected by an ion strength sensor 60 and a water pressure sensor 61, and the quality of pure water 33 is detected by a water quality detection sensor 71, respectively. In the ultrafiltration of the reverse osmosis membrane means 3, when the ionic strength of the feed water 20 and the water to be treated 41 is increased, these water pressures are increased. As the ionic strength and water pressure of the supply water 20 and the water to be treated 41 increase, the resulting pure water 33 has a higher ionic strength. If the ionic strength of the pure water 33 falls within the range according to the purpose of use, and the ionic strength and water pressure of the supply water 20 and the water to be treated 41 fall within the range where the ionic strength of the pure water 33 can be maintained, the supply water 20 The supply amount is kept constant (for example, the same amount as the use amount of pure water 33), it can be operated without draining the treated water 41, the amount of water discarded can be reduced, and maintenance work And costs can be minimized.

In the present embodiment, in practice, when the water pressure and ionic strength of the supply water 20 and the water to be treated 41 are increased by the control device (not shown) and the ionic strength of the pure water 33 is increased, the supply water 20 and any one or more of the following processes for reducing the water pressure and / or ionic strength of the water 41 to be treated are performed. That is,
(1) Lowering the water pressure of the supply water 20 and the treated water 41 by lowering the pressure applied by the pressurizing means 6;
(2) Decreasing the ionic strength of the water to be treated 41 by increasing the electric power supplied from the power supply 44 of the water quality improvement means 4 and precipitating the scale component of the concentrated water 34 more.
(3) The valve 49 connected to the drain pipe 46 of the water quality improvement means 4 is opened to discard the concentrated water 34 having high ionic strength, thereby reducing the ionic strength and water pressure of the water to be treated 41.
(4) The ionic strength of the supply water 20 and the for-treatment water 41 is lowered by increasing the supply amount of the supply water 20 by the valve 22 connected to the supply means 2. By controlling the water pressure of the feed water 20 and the water to be treated 41, the reverse osmosis membrane of the reverse osmosis membrane means 3 is not subjected to water pressure, and no load due to water pressure is applied to other locations inside the apparatus. Effort and cost are minimized.

  The adhesion of the scale to the cathode 42 can be adjusted by controlling the pressure of the pressurizing device 6 and the manual valve 35 manually. That is, if the flow rate of the concentrated water 34 supplied to the water quality improvement means 4 is increased by these controls, the time for the concentrated water 34 to contact the cathode 42 is shortened, so that the scale thickness and size of the cathode surface grow. It becomes difficult. Further, the water pressure directly hitting the cathode 42 is increased, and it is difficult to grow even if the scale is peeled off. In particular, the operation of the manual valve 35 can prevent the scale from growing too much and causing the electrolysis ability of the electrode to decrease, and causing problems such as physical water flow in the water quality improvement device 4.

  The water to be treated 41 is supplied to the reverse osmosis membrane means 3 together with the supply water 20 and ultrafiltered, but the scale components 47a, 47b and 47c are removed and the ionic strength is reduced, so that the ultrafiltration is excessive. Since no high pressure is required and the scale is not released in water, the reverse osmosis membrane is not clogged and the burden on the reverse osmosis membrane means 3 is reduced. Therefore, the maintenance and replacement of the reverse osmosis membrane means 3 can be minimized.

Removal of the solid scale deposited and held on the cathode 42 is performed as follows. First, the cathode 42 is taken out from the treatment tank 40, and water pressure is applied by water discharge washing from a water supply hose. Usually, when a metal crystal is attached to a smooth surface and grows, it takes a plate-like or needle-like crystal, but the massive solid scales 47a, 47b, and 47c are formed on the surface of the uneven cathode 42. As a result, it grows in the form of coarse sludge in which grains and foams are adhered to each other, so-called multi-grain sludge. These multi-grain sludges, that is, the small solid scales 47a and 47c and the film-like solid scale 47b are all in contact with the sprayed coating 42a only in a small area of the contact surface 42g. Easily peels off and flows down. Therefore, the solids 47a, 47b and 47c can be easily removed from the cathode 42 by these operations. The dropped solid scale becomes a small piece of metal, so-called solid metal flakes, and can be easily removed or recovered. Incidentally, the piping or we treated water 41 without turning cathode 42 to the processing tank 40 by circulating at high speed, can be removed by applying pressure to the surface of the cathode 42. Further, the solid scale can be peeled off with a light rubbing force by brushing or the like. These and water pressure may be used in combination.

  As a modified embodiment of the present embodiment, the reverse osmosis membrane provided in the reverse osmosis membrane means 3 can be made of, for example, polyamide or PVA as a constituent material and shaped like a spiral, a hollow fiber, a flat plate or the like. In this case, when the supply water 20 contains chlorine, a filter provided with activated carbon between the water quality improvement means 4 and the reverse osmosis membrane means 3 so that the hypochlorous acid generated by electrolysis does not react with the reverse osmosis membrane means. It is desirable to provide a means for removing hypochlorous acid.

  The present invention is not limited to the above-described embodiments, and variously modified forms are included in the technical scope without departing from the gist of the invention described in the claims. .

  The present invention is widely useful for medical and industrial water purification, and can contribute not only to life and industry but also to environmental problems.

DESCRIPTION OF SYMBOLS 1 Pure water manufacturing apparatus 2 Supply means 3 Reverse osmosis membrane means (concentration membrane means)
4 Water quality improvement means 5a Supply path 5b, 5c, 5d Pipe 6 Pressurization means 7 Pure water storage means 20 Supply water 21 Filters 22, 49, 72 Valve 23 Check valve 31 Pure water side section 32 Concentrated water side section 33 Pure Water 34 Concentrated water 35 Manual valve 40 Treatment tank 41 Water to be treated 42 Cathode 42a Spray coating 42b Metal material 42c Fluoride pitch 42d Electrode body 42e, 43e Electrode terminal portions 42f, 43f Cover member 42g Contact surface 43 Anode 44 Power supply 45 Conductor 46 Drain pipes 47a, 47b, 47c Solid scale 48 Scale component 60 Ionic strength sensor 61 Water pressure sensor 70 Use point (pure water means)
71 Water quality detection sensor

Claims (10)

A supply means having a supply path for supplying supply water; a concentration membrane means for filtering the supply water to obtain pure water and concentrated water; and a pure water connected to the concentration membrane means for receiving supply of pure water Water means, and supply of concentrated water connected to the concentrated membrane means, provided with a cathode and an anode, to improve the water quality by electrolyzing the concentrated water and to connect the concentrated water improved in water quality to the supply path Water quality improving means for supplying to the concentrated film means, the cathode of the water quality improving means is provided with a sprayed coating made of a material containing a metal material and a fluoride pitch on the surface,
An apparatus for producing pure water, characterized in that the surface of the thermal spray coating is provided with irregularities in which a fluoride pitch protrudes from the surface by 1 to 100 μm.   The diameter of the said fluoride pitch of the said cathode is 30-150 micrometers, The pure water manufacturing apparatus of Claim 1 characterized by the above-mentioned. A supply means having a supply path for supplying supply water; a concentration membrane means for filtering the supply water to obtain pure water and concentrated water; and a pure water connected to the concentration membrane means for receiving supply of pure water Water means, and supply of concentrated water connected to the concentrated membrane means, provided with a cathode and an anode, to improve the water quality by electrolyzing the concentrated water and to connect the concentrated water improved in water quality to the supply path Water quality improving means for supplying to the concentrated film means, the cathode of the water quality improving means is provided with a sprayed coating made of a material containing a metal material and a fluoride pitch on the surface,
The diameter of the said fluoride pitch of the said cathode is 30-150 micrometers, The pure water manufacturing apparatus characterized by the above-mentioned.   The pure water production apparatus according to any one of claims 1 to 3, further comprising pressure control means for detecting a water pressure of the supply water and controlling the water pressure.   5. The apparatus for producing pure water according to claim 1, further comprising an electrolysis control unit that detects the ionic strength of the concentrated water and controls the electrolysis of the water quality improvement unit. .   The said pure water means is further provided with the pure water storage means which stores pure water, The said pure water storage means is provided with the water quality detection means, The any one of Claim 1 to 5 characterized by the above-mentioned. Pure water production equipment.   The pure water production apparatus according to claim 1, further comprising a flow rate control unit that controls a flow rate of supplying the concentrated water to the water quality improvement unit. A step of obtaining concentrated water by a reverse osmosis membrane, a step of improving the water quality of the concentrated water by electrolytic treatment using a cathode having a thermal spray coating formed of a material containing a metal material and a fluorinated pitch on the surface, and the water quality A step of supplying improved concentrated water and supply water to the reverse osmosis membrane and performing ultrafiltration to obtain pure water and the concentrated water;
The method for producing pure water, characterized in that the thermal spray coating has a surface on which irregularities formed by fluorination pitch protruding from the surface by 1 to 100 μm are used. A step of obtaining concentrated water by a reverse osmosis membrane, a step of improving the water quality of the concentrated water by electrolytic treatment using a cathode having a thermal spray coating formed of a material containing a metal material and a fluorinated pitch on the surface, and the water quality A step of supplying improved concentrated water and supply water to the reverse osmosis membrane and performing ultrafiltration to obtain pure water and the concentrated water;
The method for producing pure water, wherein a diameter of the fluoride pitch of the cathode is 30 to 150 μm.   A step of detecting the ionic strength and water pressure of the concentrated water, and a step of decreasing the pressure applied to the reverse osmosis membrane according to the detected increase in the ionic strength and water pressure or increasing the power applied in the electrolytic treatment. The method for producing pure water according to claim 8 or 9, further comprising:

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