JP2611183B2 - Fluid circulation deaerator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deaerator for removing a predetermined (unnecessary) dissolved gas from water or other fluid.

[0002]

2. Description of the Related Art An apparatus for purifying water and other solution fluids, as typified by a so-called pure water production apparatus, that is, for removing solid solutions (impurities) and undesirable dissolved gases from a fluid as much as possible. The need for such equipment will increase in various fields, including the semiconductor industry, the pharmaceutical industry, the food industry, the analysis industry, and the water supply and sewerage business, as well as now and in the future. Seem.

For example, in the semiconductor industry, there is a demand for not only removing undesirable inorganic and organic impurities (including microorganisms such as bacteria) but also thoroughly removing gases, such as oxygen, dissolved in pure water. There is. In a semiconductor integrated circuit construction technology in which the design rules of wiring patterns are extremely fine as in recent years, for example, even a single bacterium may cause a short circuit. Further, in the case where hydrogen termination is performed by immersing the silicon surface in a hydrofluoric acid solution, the oxidation reaction is more dominant than the chemical reaction for realizing the hydrogen termination, and the remaining dissolved oxygen is also a serious problem.

[0004] First, from the viewpoint of degassing of dissolved gas from a fluid only, there are a bubbling method and a vacuum degassing method as conventional techniques suitable for this. Since the dissolved gas amount keeps an equilibrium in proportion to the external partial pressure, the dissolved amount is reduced by reducing the external partial pressure of the dissolved gas. To achieve this in the bubbling method, for example, when removing dissolved oxygen, a large amount of high-purity inert gas (typically argon gas) is passed through the fluid as fine bubbles. This technique is often employed not only in the semiconductor industry, but also generally in electrochemical lab sites. This is because dissolved oxygen and, in some cases, dissolved nitrogen are more likely to be active reactive species than the reaction intended in the experiment.

On the other hand, in the vacuum degassing method, the external partial pressure of dissolved gas such as oxygen is reduced by literally setting the fluid outer space to a vacuum (low pressure) environment. In an actual apparatus, a fluid to be treated is sprayed into a vacuum chamber in order to increase the efficiency.

On the other hand, such dissolved gas degassing is called
It is not a single function device, but a pure water production system as shown in FIGS.
60 and 70 are provided. Referring to the conventional pure water producing apparatus 60 shown in FIG. 7, raw water Wg supplied from water supply is first input to a primary pure water system 61, where it is roughly purified. The primary pure water system 61 is generally composed of an activated carbon filter, several filters having different pore sizes, a reverse osmosis membrane, and the like.

[0007] The primary treated water Wo treated by the primary pure water system 61 is supplied to a tank 64 by opening a flow path opening / closing valve 63 and operating a water supply pump 62, and thereafter, the water supply pump
With the operation of 65, the water is input to the secondary pure water system 66. The secondary pure water system 66 is also called an ultrapure water system, and is composed of an ultraviolet excitation light source, an ion exchange resin membrane, an activated carbon filter, a fine-diameter filter, and the like. If it exceeds, it can be taken out as pure water (ultra pure water) Wp by opening the flow path opening / closing valve 67 provided in the output flow path, and when it does not exceed the reference value or when water is not taken out Is returned to the input side again.

On the other hand, in the case of the conventional pure water producing apparatus 70 shown in FIG. 8, the intake line has a closed circulation system. That is, the primary treated water Wo given from the primary pure water system 61 to the secondary pure water system 66 under the operation of the water supply pump 62 via the flow path opening / closing valve 63 was treated by the secondary pure water system 66. After that, it is output to the circulation channel 71. In the case shown in the drawing, if the attached flow passage opening / closing valves 74 are selectively opened to a plurality of water intake lines provided for the circulation flow passage 71, the output pure water of the secondary pure water system 66 is passed therethrough. Wp is withdrawn, but pure water Wp that has not been withdrawn is opened with a circulation flow path opening / closing valve 72 to prevent quality deterioration due to stagnation.
By operating 73, it is returned to the input of the secondary pure water system 66.

[0009]

However, both the pure water producing apparatuses 60 and 70 currently provided as described above have problems. In the case of the device 60 shown in FIG. 7, bacteria may be generated in the water storage tank 64. Primary pure water system
It can be considered that there is almost no bacteria in the primary treated water Wo that has passed through 61, however, the disinfection in the tank 64 is incomplete, or for example, the wall junction of the tank 64 or the flow path If there is a slight gap or the like at the joint portion with the constituent pipe, bacteria may enter the tank 64. If the amount of contamination is small, such bacteria often die immediately. However, when the amount is a certain amount, the bacteria win the growth, causing an increase in organic matter and concentration of specific elements. Such a problem is likely to occur when the frequency of use of the device is low, during maintenance of the device, during a long period of suspension due to a long vacation of the company using the device, and also in a portion other than the tank 64, for example, a water intake line.

On the other hand, a pure water producing apparatus shown in FIG.
In the case of 70, such disadvantages are considerably improved. That is, since water stagnation near the water intake causes the generation of such bacteria, pure water other than water to be taken is returned to the secondary pure water system 66 again, so that the water quality is kept good. . However, the frequency of use of the secondary pure water system 66 having a sophisticated internal mechanism is increased, thereby increasing the burden and shortening the service life. Further, although it may be better compared to the conventional device 60 shown in FIG. 7, in particular, in the flow path portion up to the input to the secondary pure water system 66 and in the circulation flow path,
The fear of bacterial growth remains, as no active functional devices for killing bacteria are incorporated.

Here, from the viewpoint of the active eradication of bacteria, bacteria cannot survive without oxygen, which ultimately leads to the problem of reducing the concentration of dissolved oxygen in the fluid output from the device. In other words, overcoming the problem of reducing dissolved oxygen required at the time of manufacturing a semiconductor device as described above can simultaneously produce an effect of suppressing the generation of bacteria.

However, the vacuum degassing method and the bubbling method described above, which are extremely effective only from the functional viewpoint of reducing the dissolved oxygen concentration, can be used in the conventional pure water producing apparatuses 60 and 60 shown in FIGS. It would be extremely difficult to actually incorporate it into an existing fluid purification device represented by 70 as a device,
Often impossible. For example, the bubbling method requires a fluid storage tank for performing the bubbling, and it is impossible to perform bubbling while maintaining a stable fluid flow in the flow path. This is because the generation of bubbles in the fluid flow path generally configured as a pipe impedes the flow of the fluid. In that sense, it cannot be incorporated in the circulation system including the circulation flow channel 71 in the conventional device 70 shown in FIG. In contrast, with the conventional device 60 shown in FIG.
Since it has the tank 64 in the first place, for example, it may be modified to perform bubbling here.However, it is possible to almost eliminate unnecessary dissolved gas only by the bubbling method, and to shorten the processing time. In order to achieve high efficiency, a relatively large apparatus (tank 64) is required, and a large amount of expensive high-purity inert gas must also be used. It is also difficult to recover the gas used for bubbling.

In the case of the vacuum degassing method, the size of the apparatus is so large that it is incomparable to the bubbling apparatus. It is theoretically impossible to incorporate the apparatus into a pure water production apparatus as shown in FIGS. Is possible but not actually possible. When this method is followed, in order to prevent the backflow of pure water from the vacuum chamber, water must be injected from a height higher than 10 m, which is a water height equivalent to at least one atmosphere. Therefore, the construction of a huge facility called a vacuum degassing tower is inevitable, which is not only uneconomical but also extremely inflexible.

On the other hand, not only in the production of pure water but also in the purification of fluids in a general sense, there is a growing need to drive out undesired dissolved gases from the fluid to be treated as much as possible. For example, (1) reduce the amount of oxygen in water to reduce the rate of spoilage of foods, etc., (2) reduce the amount of dissolved oxygen in the water flow in pipes to prevent rust in various pipes such as water and sewer pipes. I want to lower, (3) I want to remove dissolved gas that is a factor that hinders the target reaction from the solution to improve the precision of chemical reaction control using various solutions, (4)
In chromatographic analysis, various gases dissolved in the solution to be analyzed cause spectral peaks to appear as noise, and therefore, in order to increase the signal-to-noise ratio and increase the analysis accuracy, it is desirable to reduce the amount of dissolved gas in the solution. ) Radiation detection using isotopes is problematic for radioactive gas such as radon dissolved in the target solution, so we want to remove it. (6) Used in high pressure environments such as turbines In the case of fluids, the dissolved gas is likely to separate and become a gas-liquid mixed state, which may lead to a serious accident, which may lead to serious accidents. Therefore, it is necessary to remove dissolved gas as much as possible. is there.

[0015] In order to meet such various demands,
First of all, like the conventional bubbling method and vacuum degassing method,
It should not be expensive in terms of equipment structure or where it is used or where it is to be used, or should not be expensive in terms of maintenance and maintenance costs. Must. In addition, it must be satisfactory in terms of performance and must be able to efficiently and reliably remove unnecessary dissolved gases from various fluids represented by pure water. The present invention has been made from such a point of view.

[0016]

In order to achieve the above object, the present invention provides a method in which a fluid to be treated can flow into a closed circulation flow path, and a small-sized part of the closed circulation flow path is provided. Provided is a fluid circulation deaeration device provided with a deaeration unit that requires only a device configuration. That is, in the present invention, first, in the closed circulation channel that circulates the fluid by operating the circulation pump, a pair of openings in which the fluid flowing in from one opening flows out from the other opening, and flows in from the one opening. A hollow cylindrical member having a cylindrical peripheral wall through which the fluid flows along the inner surface when the fluid flows toward the other opening is inserted in series. Then, after part or all of the peripheral wall of the hollow cylindrical member is formed of a gas permeable membrane, the external space of the gas permeable membrane is set to a negative pressure, or a gas other than a predetermined dissolved gas to be removed is removed. A deaeration unit for providing a positive pressure by filling, and further, a fluid inflow path having a flow path opening / closing valve to selectively flow the fluid to be processed into the closed circulation flow path,
In order to selectively remove the processed fluid from the closed circulation channel, a fluid outflow channel having a channel opening / closing valve is provided.

The present invention also proposes a fluid circulation deaerator in which a closed tank capable of temporarily storing fluid is provided in a part of the closed circulation flow path. In this case, the tank forms a part of the closed circulation channel. Therefore, the fluid inflow path may be open to this tank,
A fluid outflow channel may be open to this tank,
Alternatively, both may be open to the tank.

Further, according to the present invention, a filter for removing impurities is provided in the closed circulation flow path, or a filter for removing impurities is provided in the fluid outflow path and provided in the fluid outflow path. There is also proposed a fluid circulation deaerator in which a filter for removing impurities is provided in a portion between the passage opening / closing valve and the closed circulation passage.

[0019]

FIG. 1 shows a schematic configuration of a main portion of a fluid circulation deaerator 100 according to an embodiment of the present invention. First, there is a closed circulation flow path 10 that can circulate the processing target fluid F containing a predetermined gas to be removed by operating the circulation pump 15. This closed circulation channel 10 can be actually constructed using existing commercially available hollow pipes.

A part of the closed circulation flow path 10 is provided with a deaeration section 20. Part or all of the peripheral wall of the closed circulation flow path 10 in the deaeration section 20 is a gas permeable membrane 21, and an external space 22 of the gas permeable membrane 21 is schematically shown by an arrow 23 in FIG. As shown, the gas is exhausted to a negative pressure, or, as indicated by arrow 24, to a positive pressure by the pressure of a gas other than the dissolved gas to be removed.
Since the outer space 22 of the gas permeable membrane 21 is actually conveniently limited to a predetermined volume range, the outer space 22 of the gas permeable membrane 21 is sealed inside the sealed container 25 with high sealing properties. It is space 22.

The circulation path of the fluid F is configured as described above. However, in order to allow the fluid F to be treated to selectively flow into the closed circulation flow path 10, it is opened at a part of the closed circulation flow path 10. In order to selectively remove the treated fluid F from the fluid inflow channel 11 and the closed circulation channel 10, a fluid outflow channel 12 which is also open to a part of the closed circulation channel 10 is provided.
The fluid outflow passage 12 is provided with flow passage opening / closing valves 13 and 14 which can selectively open and close the flow passages, respectively. Further, in this embodiment, in order to remove undesired dissolved substances such as solid solutions from the fluid F in addition to the dissolved gas, the filter 16 which may be a known one is provided with a closed circulation flow path.
It is provided in 10.

Here, a specific configuration of the deaeration unit 20 can be desirably a configuration as shown in FIG. First,
The gas permeable membrane 21 provided on a part of the peripheral wall of the closed circulation flow path 10,
The hollow cylindrical member 31 is configured as a peripheral wall. That is, there is a pair of openings 26, 26 through which the fluid F flowing from one side flows toward the other, and a peripheral wall of a hollow cylindrical member 31 having an inner hollow cylindrical portion connecting the pair of openings 26, 26. The gas permeable membrane 21 is provided for at least a part of the above. And especially,
In this embodiment, all of the peripheral wall of the hollow cylindrical member 31 has a tubular shape (it may be called a tube shape or a hose shape because it is often a considerable length as described later). The hollow cylindrical member 31 is configured by the hollow cylindrical gas permeable membrane 21 itself. Incidentally, the gas permeable membrane 21 referred to in the present invention,
The gas to be treated does not pass through, but the gas to be degassed refers to the one with an infinite number of holes with a fine diameter enough to pass through, and such a member, as will be given later, as an example,
It is already readily available on the market.

In this embodiment, the hollow cylindrical member 31 is housed in the closed container 25 as described above, so that the hollow cylindrical member 31 or the outer space 22 of the gas permeable membrane 21 is substantially the same as the hollow cylindrical member 31. The internal space of the closed container 25 for storing the hollow cylindrical member 31
22. Any one of an exhaust device and a pneumatic device can be connected to such a sealed container 25. That is, if an exhaust device 32 that can be constituted by a general exhaust pump 33 is connected and operated, the external space 22 of the gas permeable membrane 21 which is the internal space of the closed vessel 25 is exhausted as shown by an arrow 23. And the pressure becomes relatively negative. On the other hand, a gas pressure feeding device 34, which can be constituted by, for example, a compressor 37, is connected to the closed vessel 25, and if this is operated, an air gas 36 of a type that can be fed into the fluid F is stored. The incoming gas 36 from the gas source 35 is supplied under pressure into the internal space of the sealed container 25 (the external space 22 of the gas permeable membrane 21), and the internal space 22 becomes relatively positive pressure. . However, the gas pumping device 34 and the gas source 35 do not necessarily have to be separate functional members. For example, in the case of a so-called gas cylinder 38, this serves as both the gas pumping device 34 and the gas source 35.

A pair of open ends of the hollow cylindrical member 31, or the hollow cylindrical gas permeable membrane 21 in this embodiment, are connected to inner ends of connectors 27, 27 provided in the closed container 25, respectively. , The outer ends of these connectors 27, 27, respectively,
The pipe means constituting the closed circulation flow path 10 is partially removed and connected to one of the facing open ends formed. Thereby, the hollow cylindrical member 31 or the hollow cylindrical gas permeable membrane 21 in this embodiment is inserted in series into the closed circulation flow path 10.

The fluid circulation deaerator 100 shown in FIG. 1 having the deaerator 20 shown in FIG. 3 can be used as follows. After opening the flow path opening / closing valve 13 attached to the fluid inflow path 11 and introducing a predetermined amount of fluid F into the closed circulation flow path 10, the flow path opening / closing valve 13 is closed, and then the circulation pump 15 is operated and closed. The fluid F introduced into the circulation channel 10 is circulated through the closed circulation channel 10. At this time, if the exhaust device 32 is used among the exhaust device 32 and the gas pumping device 34 shown in FIG. 3, the inside of the cylindrical gas permeable membrane 21 forming a part of the closed circulation flow path 10 Every time it passes through the gas permeable membrane 21
As a result, the dissolved gas in the fluid F is drawn toward the gas permeable membrane 21 having a relatively lower partial pressure and dissolved in the membrane 21. Further, the gas dissolved in the gas permeable membrane 21 is drawn toward the external space 22 having a lower partial pressure, and is finally discharged to the external space 22 having the negative pressure.

As is apparent from such a mechanism,
The amount of deaeration from the fluid F depends on the degree of negative pressure, the flow rate of the fluid F,
Not only does it vary depending on various parameters such as the length of the hollow tubular member 31 or the tubular gas permeable membrane 21, but also how many times it passes through the gas permeable membrane 21 (the number of circulations in the closed circulation flow path 10 How many times). Of course, the greater the effect, the greater the degassing effect, but this is a balance between processing time. Therefore, if the number of circulations is allowed to be large, the length of the gas permeable membrane 21 can be shortened, which leads to a reduction in the size of the device.

In any case, if a necessary degree of deaeration is performed from the fluid F by such deaeration processing, the flow opening / closing valve 14 attached to the fluid outflow path 12 is opened to thereby determine the amount of dissolved gas. Can be obtained sufficiently.

However, in FIG. 3, instead of exhausting the outer space 22 of the gas permeable membrane 21 by the exhaust device 32, a gas pumping device 34 can be used to degas a predetermined gas to be removed from the fluid F. I can do it. In other words, a gas other than the gas to be removed from the fluid F is selected as the gas for intake 36 obtained from the gas source 35, and this gas is supplied to the closed container 25 by the gas pressure feeding device 34.
When the dissolved gas to be removed from the fluid F is supplied to the internal space 22 by pressurization, the cylindrical gas permeable membrane
The partial pressure on the side of the outer space 22 opposed to the outer space 21 is lower, and as a result, the dissolved gas of the fluid F passes through the same process as before and exits to the outer space 22 of the gas permeable membrane 21. become.
Therefore, such a degassing process is a process of replacing the gas not desired to be dissolved by the gas 36 which may be dissolved in the fluid F.

According to this principle, the outer space 22 of the gas permeable membrane 21 has a negative pressure when the dissolved gas to be removed from the fluid F is to be removed, and has a positive pressure when the dissolved gas is to be removed from the fluid F. Since it is sufficient that such a pressure relationship is generated, the absolute pressure value of the internal space 22 of the sealed container 25 (the outer space 22 of the gas permeable membrane 21) is the same as that of the outside of the sealed container (for example, 1 atm for both inside and outside). Even better) in some cases. Further, in order to prevent the purity of the gas for air supply 36 supplied into the closed vessel 25 from being lowered, the closed vessel 25 is also provided with an exhaust port (not shown),
It is also possible to adopt a configuration in which the inlet gas 36 supplied from the gas cylinder 38 always passes through the inside of the closed vessel and exits from the exhaust port.

FIG. 2 shows a fluid circulation deaerator 100 according to a second embodiment of the present invention. The same reference numerals as those described above indicate the same or similar components. However, different points from the embodiment apparatus shown in FIG.
Desirably that a closed storage tank 40 is interposed,
In other words, a part of the closed circulation channel 10 is a storage tank 40. Other configurations may be the same as those of the apparatus shown in FIG. 1, and the configuration shown in FIG. 3 may be employed as a specific configuration example of the deaerator 20 interposed in the closed circulation flow path 10. it can. However, the closed circulation channel 10
The fluid inflow path 11 with the flow path opening / closing valve 13 for selectively supplying the fluid F may be provided for the newly provided storage tank 40 as shown in the drawing, or in some cases. The fluid outflow path 12 with the flow path opening / closing valve 14 may also be provided for the storage tank 40 as shown by dashed lines 14 ′ and 12 ′ in the figure. . Rather, as shown by phantom lines in FIG. 2 and indicated by dashed reference numerals 11 ′ and 13 ′, the fluid inflow path 11 ′ with the flow path opening / closing valve 13 ′ is similar to the previous embodiment. The storage tank 40 may be provided so as to open directly to the closed circulation channel 10, and in this case, the storage tank 40 may not have an opening portion other than the portion opened to the closed circulation channel 10. Further, the fluid inflow path 11 indicated by a solid line may be used as a fluid outflow path, and the fluid outflow path 12 may be used as a fluid inflow path.

In the embodiment apparatus 100 shown in FIG. 2 as well, the closed circulation flow path 10 in the deaeration section 20 is operated in the same manner as the operation method of the embodiment apparatus 100 shown in FIG.
The dissolved gas to be removed from the fluid F supplied therein can be effectively degassed. Moreover, as compared with the embodiment apparatus 100 shown in FIG. 1, the amount of fluid discharged at one time can be increased by the amount of the storage tank 40. In the present invention, the storage tank 40 stores the fluid F degassed by the degassing section 20 in the closed circulation flow path 10 (and as described above, in order to obtain a necessary degassing amount). The circulation degassing process can be performed as many times as necessary), so that the gas to be degassed is oxygen and the fluid F
By repeatedly reducing the dissolved oxygen concentration in the storage tank 40 to an extremely low concentration by deaeration, unlike the tank 64 used in the conventional pure water production apparatus 60 described with reference to FIG. It is not necessary to cause the generation of bacteria. However, desirably, the surplus space in the storage tank 40 other than the space in which the fluid F is stored is a gas which may be dissolved in the fluid F, for example, as described above, it is necessary to remove oxygen. And nitrogen or the like may be dissolved, it is preferable to fill them with argon or nitrogen.

Here, a specific example of an experiment conducted to obtain pure water having a small amount of dissolved oxygen as the fluid F using the apparatus 100 of the embodiment shown in FIG. 2 will be described. Configuration example of the experimental apparatus is as shown in FIG. 4, FIG. 2 primary treatment water W _O treated with known existing primary pure water system 61 by the water pump 62
Was supplied into the storage tank 40 having a capacity of 100 liters from the fluid inflow path 11 shown in FIG. Of course, at this time, only the flow passage opening / closing valve 13 attached to the fluid inflow passage 11 is opened, and the flow passage opening / closing valve 14 attached to the fluid outflow passage 12 is closed. The primary pure water system 61 used was an activated carbon filter and a 1
The filter was constructed using a filter having a hole having a diameter of about μm and a reverse osmosis membrane, and an empty space in the tank 40 was filled with high-purity nitrogen.

After filling the storage tank 40 with the primary treated water W _O , the flow opening / closing valve 13 of the fluid inflow path 11 is closed, and the water supply pump 62
After stopping the operation, the circulation pump 15 is operated to flow the water in the tank 40 into the closed circulation flow path 10 at a flow rate of 1 liter / min.
Passed. In the deaeration section 20, at ambient temperature of 20 ℃,
The inside exhaust device 32 was selected, and the inside of the sealed container 25 was exhausted to several tens Torr by the emblem pump used as the exhaust pump 33. The gas permeable membrane 21 used as the hollow tubular member 31 described above in the degassing section 20 was obtained from ERC Co., Ltd., located in Kawaguchi City, Saitama Prefecture, under the model number "ERC30".
1601 ", which is about 1 cm in inner diameter and about 10 m in length. Therefore, although there is no doubt that the gas permeable membrane 21 is in the shape of a hollow cylinder, it is a long tube or hose in terms of the five senses.
Instead of being stretched straight and housed in the closed container 25, it was bent and housed in a pipe-shaped closed container 25 made of vinyl chloride of about 1 m in length. Of course, there is no restriction on the material of the sealed container 25 in principle.

In this way, the saturated amount of 8.1 ppm
By passing once through the deaeration unit 20 the primary treated water W _{O in} which the dissolved oxygen was dissolved, the dissolved oxygen amount was already reduced to 1.2 ppm. Therefore, after repeating this circulation three times, the flow path on-off valve
14 was opened, water was taken from the fluid outflow channel 12, and measured by a dissolved oxygen meter, the oxygen dissolved amount was greatly reduced to 80 ppb. In addition, in order to remove impurities other than dissolved oxygen at the time of water intake, as a filter 16 shown in FIG. 2, a filter 16 according to Nippon Millipore Limited, located in Shinagawa-ku, Tokyo, Japan, was used.
The product name "Milli QSP LowTOC" was used. This filter is composed of an activated carbon filter, a filter having a hole having a diameter of about 1 μm, and an ion exchange resin membrane, and is configured to be capable of irradiating ultraviolet light.
Ω, can permeate pure water with an organic concentration of 5 ppb or less at 0.8 l / min, and 0.07 ppb of alkali metals such as sodium
Below, other metals can be removed down to 0.1ppb or less. The performance of this filter is
The provision of 20 did not hinder anything. However, since the amount of circulating water returning to the tank 40 during intake is reduced, as shown by the phantom line in FIG.
It was provided near the entrance opening to 40.

The above-mentioned experimental apparatus was continuously operated for one year, but no bacteria or the like were found in the storage tank 40 by inspection with a sampler.

Although the effect of the present invention can be confirmed by this fact, in order to verify the effect of reducing the dissolved oxygen concentration, a silicon substrate having an oxide film on the (111) surface is etched with a hydrofluoric acid solution and oxidized. Hydrogen termination after removing the film was attempted. The hydrofluoric acid used was of EL grade. Conventionally, the silicon surface is immediately oxidized by dissolved oxygen contained in pure water used before and after such treatment, and hydrogen termination cannot be realized, or at least rarely. However, when a series of chemical treatments for hydrogen termination was performed using pure water treated by the present fluid circulation deaerator 100, hydrogen termination, which is the inferior reaction process, was not rejected by the predominant oxidation reaction. It was confirmed that it could be realized.

That is, FIG. 5 is a faithful tracing and drawing of a scanning tunneling microscopic photograph of the surface of the silicon substrate on which the hydrogen termination treatment was attempted. In FIG. 5, the rounded protrusion that looks whitish is a hydrogen atom. And the (111) silicon substrate surface is terminated with hydrogen in the form of trihydride.
In fact, such structures have been built over a considerable area.

As can be understood from such experimental examples,
The practical effect of using the fluid circulation deaerator 100 of the present invention is extremely large. Unnecessary dissolved gas, such as pure water, can be efficiently and effectively removed from a given fluid with a fairly small device configuration. The flexibility is incomparable to those required for large, immovable and expensive equipment, such as those recognized in the conventional vacuum degassing method. Further, as is apparent from the configuration of the degassing section 20, the predetermined gas can be continuously degassed without impairing the flow of the fluid F. For example, in place of the operation of the above-described exhaust device 32, a predetermined intake gas 36 such as argon or nitrogen filled in the gas source 35 from the gas pumping device 34 is introduced into the fluid F. This also applies to the case where a dissolved gas such as oxygen to be removed is expelled from the fluid F. According to this principle, a gas having a saturation amount or more does not dissolve in the fluid F, and bubbles are not generated and the fluid flow is not impaired. Therefore, the device 100 of the present embodiment is significantly superior to the deaeration or air inlet method using only the conventional bubbling device, and further, the tank becomes so large that the efficiency of the conventional bubbling method is increased. Although it is necessary to increase the size and to collect a large amount of intake gas that leaks with this, the device 100 of the present embodiment does not need to collect the gas, and therefore, for example, it may leak into the atmospheric environment such as hydrogen or ozone. The fluid circulation deaerator 100 of this embodiment can be suitably used even when dealing with undesired gas, and excellent results can be obtained in terms of safety and environment.

Incidentally, high-purity argon gas is supplied from the high-purity argon gas cylinder 38 serving as the gas pumping device 34 and the gas source 35 into the closed vessel 25 at a gauge pressure of 1 atm via a regulator not shown in FIG. The water which had the dissolved oxygen of the above-mentioned saturation amount of 8.1 ppm was
The concentration of dissolved oxygen was reduced to 900 ppb or less even with a single pass at the above flow rate. Therefore, it can be seen that this pneumatic principle can also be used in realizing the present invention.

In the embodiment apparatus 100 shown in FIGS.
Although not directly related to the reduction of dissolved oxygen, a filter 16 is provided in the closed circulation flow path 10 for using the apparatus using the present invention as a practical apparatus and having a high impurity removal function. This certainly increases the filtering function, but may shorten the life of the filter 16 in some cases. Therefore, as shown by a virtual line in the figure, the filter 16 may be changed to be provided in a portion located in the fluid outflow channel 12 and between the channel on-off valve 14 and the closed circulation channel 10. . FIG.
When the fluid outflow channel 12 is opened in the tank 40 as shown by a virtual fluid outflow channel 12 ′,
This filter 16 is also changed to the position indicated by reference numeral 16 '. Such a change would, of course, extend the life of the fluid F, as it would only pass through this filter 16 when it was withdrawn through the fluid outlet 12. Further, in practice, even in this case, the impurity removing ability is not so inferior to the case where the filter 16 is provided in the closed circulation channel 10. However, optimally, as shown by reference numerals 17 and 18 in FIGS. 1 and 2, the first filter 17 is provided in the closed circulation passage 10 and the closed circulation passage 10 and the fluid outflow opening / closing valve 14 are connected to each other. A second filter 17 is provided in the fluid outflow path between the two filters, and the precise filter as described above is used as the second filter 17, and the first filter is from 4 μm.
It is good to use a simple filter having only a hole with a diameter of about 1 μm.

Further, as in the embodiment apparatus 100 shown in FIG. 6, which is shown as a structural modification of the embodiment apparatus in FIG. 2, a plurality of fluid outflow paths 12,. ...
Are provided, and each of them is provided with a flow path opening / closing valve 14,..., So that these can be selectively opened / closed. Can be. Considering the amount of distribution, the storage tank 40
Although it is better to provide the same, the same modification can be applied to the embodiment apparatus 100 shown in FIG.

Also, when bubbling is performed according to a known technique after each distribution output of the apparatus shown in FIG. 6, the fluid F processed and output by the apparatus of the present invention is
Since the dissolved gas amount is sufficiently reduced in the first place and the gas used for bubbling is easily dissolved, not only the bubbling device itself can be reduced in size but also the bubbling processing time can be shortened. Naturally, the amount of gas used is greatly reduced, and the recovery of the used gas becomes easy. If the device 100 shown in FIG. 6 is used only for distribution, the filter 16 may not be necessary. Further, in FIG. 6, unlike the embodiment shown in FIGS. 1 and 2, the fluid F is shown to return in the closed circulation flow path 10 in the reverse direction. This indicates that the circulating direction may be either direction, and the circulating direction of the fluid F can be reversed in the embodiment shown in FIGS.

While some preferred embodiments of the present invention have been described in detail above, modifications in accordance with the gist of the present invention are optional. For example, in each of the above-described embodiments, the hollow tubular member 31 itself is constituted by the tubular (tube-like or hose-like) gas-permeable membrane 21, but the fluid F is not formed along the inner surface. Using a hollow cylindrical member 31 made of a gas-impermeable material having a rigid surrounding wall portion to flow, so as to close a window opened in at least a part of the surrounding wall,
A sheet-shaped gas-permeable film 21 may be provided. However, if the gas permeable membrane 21 is required to be considerably long in order to increase the degassing efficiency of the dissolved gas (or the gas input efficiency of the gas 36 for degassing the dissolved gas), However, the use of a product which has flexibility in itself and can be bent or twisted arbitrarily as in the case of the above-described product example can reduce the size of the degassing section 20 and thus the housing dimensions of the device of the present invention. desirable. Of course, the expression cylindrical is not limited to a circular cross section. It may have a rectangular cross section or another hollow space. It is desirable to flow smoothly, but the point is,
It suffices if the fluid F can flow inside.

Further, the flow opening / closing valves 13 and 14 provided in the fluid inflow passage 11 and the fluid outflow passage 12 are provided as closed circulation passages as possible.
It is desirable to be provided at a position close to 10. When these flow path on-off valves 13 and 14 are closed,
This is because the fluid F tends to stay in the passages in the closed circulation passages 3 and 14. These fluid inflow channel 11 or fluid outflow channel
The same applies when the tank 12 is open to the tank 40 that constitutes a part of the closed circulation flow path 10. In the tank 40, the stored fluid F is uniformly distributed as a part of the closed circulation flow path 10. Road 10
Although the fluid F can be circulated inside, the flow path portion between the tank 40 and the flow path opening / closing valve provided in the flow path opening to the tank 40 is a part where the fluid F tends to stay.

[0045]

According to the present invention, there is provided an apparatus which is simple, compact, inexpensive, has a high installation flexibility, and has a sufficient degassing effect when removing a predetermined dissolved gas from a fluid. . In view of the situation in which there was only a large vacuum deaerator or a bubbling device which was large in size and poor in installation flexibility, the fluid circulation deaerator according to the present invention is a great gospel for various industrial fields.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a main part of an embodiment of a fluid circulation deaerator configured according to the present invention.

FIG. 2 is a schematic diagram showing a main part of another embodiment of the fluid circulation deaerator configured according to the present invention.

FIG. 3 is a schematic configuration diagram of one configuration example of a deaeration unit used in the fluid circulation deaeration device of the present invention.

FIG. 4 is an explanatory diagram of an example of a device configuration in a case where a device for reducing the amount of dissolved oxygen in pure water is configured using the fluid circulation deaerator of the present invention.

5 is an explanatory diagram faithfully depicting the surface of a silicon substrate on which hydrogen termination has been attempted in a series of chemical treatments using pure water treated by the apparatus configuration example shown in FIG. 4;

FIG. 6 is a schematic configuration diagram of still another embodiment of the fluid circulation deaerator configured according to the present invention.

FIG. 7 is a schematic configuration diagram of an example of a conventional pure water production apparatus.

FIG. 8 is a schematic configuration diagram of another example of a conventional pure water production apparatus.

[Explanation of symbols]

 10 Closed circulation channel, 11 fluid inflow channel, 12 fluid outflow channel, 13 channel on-off valve, 14 channel on-off valve, 15 circulation pump, 16 filter, 17 first filter, 18 second filter, 19 check valve, 20 Degassing part, 21 Gas permeable membrane, 22 Gas permeable membrane outer space (inside of sealed container), 23 Exhaust, 24 Compressed air, 25 Sealed container, 31 Hollow cylindrical member, 32 Exhaust device, 34 Gas pumping device, 35 Gas Source, 36 Inlet gas, 38 gas cylinder, 40 storage tank, 61 primary pure water system, 62 secondary pure water system, 100 fluid circulation deaerator of the present invention.

Claims (9)

(57) [Claims] 1. A device for degassing a predetermined dissolved gas from a fluid, comprising: a closed circulation flow path for circulating the fluid by operating a circulation pump; and said fluid flowing from one opening to the other opening. And a cylindrical peripheral wall through which the fluid flows along the inner surface when the fluid flowing in from one of the openings flows toward the other opening. A hollow cylindrical member inserted in series in the flow path; a gas permeable membrane constituting a part or all of the peripheral wall of the hollow cylindrical member; Or a degassing section for making the external space of the gas permeable membrane filled with a positive pressure filled with a gas other than the predetermined dissolved gas; and opening and closing a flow path for selectively flowing the fluid into the closed circulation flow path A fluid inflow passage provided with a valve; A fluid outflow passage provided with a flow passage opening / closing valve for selectively taking out the fluid. 2. The apparatus according to claim 1, wherein the external space of the gas permeable membrane in the degassing section is an internal space of a sealed container that stores the gas permeable membrane; The internal space is evacuated to make the external space of the gas permeable membrane the negative pressure. 3. The apparatus according to claim 1, wherein the external space of the gas permeable membrane in the degassing section is an internal space of a closed container that stores the gas permeable film; A gas other than the predetermined dissolved gas to be degassed is supplied to the internal space of the closed container by the pressure feeding device, whereby the external space of the gas permeable membrane is set to the positive pressure. And equipment. 4. The apparatus according to claim 1, 2, or 3, wherein a part of the closed circulation channel is provided with a closed tank capable of temporarily storing the fluid. . 5. The apparatus according to claim 4, wherein said fluid inflow passage is open to said tank. 6. Apparatus according to claim 4, wherein the fluid outlet is open to the tank. 7. The apparatus according to claim 1, wherein a filter for removing impurities is provided in the closed circulation flow path. 8. The method of claim 1, 2, 3, 4, 5, 6, or 7.
An apparatus according to any one of claims 1 to 3, wherein a filter for removing impurities is provided in a portion of the fluid outflow channel between the flow path on-off valve provided in the fluid outflow path and the closed circulation flow path. An apparatus characterized by the above-mentioned. 9. The apparatus according to claim 1, wherein a plurality of the fluid outflow passages are provided.