Gas Replacement Device

Abstract

Flow rectifying plates 4a are tilted downward toward a first direction side, and flow rectifying plates 4b are tilted downward toward a second direction side that is opposite from the first direction. These flow rectifying plates 4a, 4b are vertically arranged in an alternating manner, and thus polluted water that flows down the rectifying plates 4a, 4b meanders while flowing downward toward a bottom section of a vessel 3. Consequently, in comparison to previous technologies in which polluted water is made to flow downward in a helical manner around a ventilation passage, resistance to the downward flow of the polluted water is not readily produced, and additionally, retention within the vessel 3 of polluted sludge (sludge) that is included in the polluted water can be suppressed. The flow rate of the polluted water can therefore be increased, and thus the processing capability of a gas replacement device 1 can be increased.

Description

[Technical Field]

[0001] The present invention relates to a gas replacement apparatus, and more particularly to a gas replacement apparatus that can improve processing capacity. [Background technology]

[0002] Water is a compound of hydrogen and oxygen, and a water molecule is formed when two hydrogen atoms and one oxygen atom bond together by sharing electrons. The bond angle between the oxygen atoms is 104.5 degrees, and the electrons of the hydrogen atoms are biased toward the oxygen atoms, which are heavier than the hydrogen atoms (higher electronegativity), so the hydrogen atoms are positively charged and the oxygen atoms are negatively charged. As a result, water molecules have a weak, positive-negative electrical attraction (dipole moment). It is thought that due to this electrical attraction, when water is in a liquid state, water molecules bind to each other through hydrogen bonds, forming clusters.

[0003] These clusters are predicted to be aggregates of 5-6 water molecules, or structures of 15-20 water molecules. When they form a cluster, they form a regular tetrahedron structure in which one water molecule contacts four other water molecules, i.e., a structure with large gaps similar to the molecular structure of ice. As a result, approximately 62% of the water volume has gaps, and it is thought that gas is trapped in these gaps, creating a "state in which gas is dissolved in water."

[0004] This can also be explained by the fact that, as shown in "Table 32.1 Saturated Dissolved Oxygen in Water (1013 hPa)" of JIS K0102 (2016 edition), the saturated dissolved oxygen content increases as the water temperature decreases. In other words, as the water temperature decreases, the molecular structure of water approaches that of ice (a regular tetrahedron with large gaps), and the drop in water temperature causes gas to contract. For this reason, as the water temperature approaches 0°C, it becomes easier for more gas to be trapped in the gaps in the water, and the saturated dissolved oxygen content is thought to increase.

[0005] One technique for dissolving gases into water is the aeration method, which involves sending air into the water. Aeration is a technique that aims to dissolve oxygen into the water by sending air into the water.

[0006] A common example of an aeration method is the aeration of fish tanks, and as is well known, with this aeration, the presence of bubbles rising to the surface in the water can be confirmed. The presence of bubbles clearly indicates that the majority of the bubbles (gas) are not dissolved in the water. Furthermore, the use of fine bubbles (nanobubbles) has been attracting attention as a recent aeration technology, but these fine bubbles can also be confirmed to exist in the water, and the amount of gas dissolved in the water is extremely small.

[0007] In other words, these aeration methods simply pass air through the water, and it is difficult to dissolve a large amount of oxygen in the water. This is thought to be because the gas trapped in the gaps in the water and the air supplied to the water are at almost the same pressure, making it difficult for the two gases to be replaced.

[0008] Aeration tanks used in wastewater treatment are designed with this kind of pressure in mind. For example, aeration tanks using the activated sludge method are generally designed to a depth of about 3 to 5 meters. The reason for designing them to such a deep depth is thought to be because experience has shown that by utilizing the pressure (water pressure) at that depth, air (oxygen) can be efficiently dissolved into water. The water pressure at a depth of 3 to 5 meters is 0.03 to 0.05 MPa.

[0009] Based on the above findings by Michio Morita, the inventor of the present application, the applicant has already developed a gas replacement device that utilizes an idea that is the exact opposite of the above-mentioned aeration method (for example, Patent Document 1, etc.). This gas replacement device pressurizes the inside of a container to above atmospheric pressure by filling it with a gas to be dissolved (for example, oxygen), and then passes water through the pressurized container.

[0010] In this gas replacement device, the gas contracts due to pressurization (Henry's law), making it easier for the gas to enter the gaps in the water. In addition, the pressure of the gas in the container is higher than the pressure of the water (gas contained in the gaps in the water) introduced into the container from atmospheric pressure. Therefore, when the water comes into contact with the gas in the container, the gas (e.g., nitrogen) originally contained in the gaps in the water is instantly replaced by the gas (e.g., oxygen) that is filled in the container.

[0011] The gas released from the gaps in the water by this replacement lowers the purity of the gas inside the container (the concentration of the gas to be dissolved), and is discharged outside the container through the ventilation path. This makes it possible to maintain the purity of the gas inside the container, and to produce gas-dissolved water in which the gas inside the container is dissolved at a high concentration.

[0012] In this way, by pressurizing the inside of the container above atmospheric pressure, the same effect can be obtained as by increasing the water depth (using water pressure) as in the above-mentioned aeration tank. That is, for example, by pressurizing the inside of the container of a gas replacement device by 0.03 to 0.05 MPa higher than atmospheric pressure using oxygen, a water depth pressure of 3 to 5 m can be reproduced, so that the necessary dissolved oxygen can be dissolved in water even in shallow water less than 3 m deep without having to install a deep water tank in wastewater treatment (for example, in water less than 3 m deep).

[0013] Furthermore, the gas-dissolved water produced by the above-mentioned gas exchange device is nearly bubble-free (non-bubble), and unlike conventional aeration methods where the presence of bubbles can be confirmed, the target gas is almost completely (100%) dissolved. The dissolution capacity of this gas exchange device is thought to be up to nearly 100 times that of conventional aeration methods. So, based on the above-mentioned water gap theory, we will consider what specific concentration is required for the state in which the gas is almost completely dissolved.

[0014] As shown in the JIS standard above, the saturated dissolved oxygen content of water under atmospheric pressure (in nature) is 14.62 ppm when the water temperature is 0°C, and the gas contained in the gaps in this water is defined as "air." Air (the atmosphere) is composed of 78.08% nitrogen, 20.95% oxygen, 0.93% argon, and other gases. Therefore, if all of the air dissolved in the water under atmospheric pressure (in nature) were replaced with oxygen, that is, if the amount of oxygen contained in the gaps in the water increased from 20.95% to 100%, the dissolved oxygen content of the water would be 14.62 ppm x (100 / 20.95)% = approximately 69.8 ppm.

[0015] It has been confirmed that when oxygen-dissolved water is produced using the above gas replacement device, the dissolved oxygen content is similar to the above-mentioned approximately 69.8 ppm. High-concentration oxygen-dissolved water is suitable for improving the environment of polluted water bodies (rivers, lakes, marshes, aquaculture facilities, etc.) because it activates microorganisms in the water, for example.

[0016] To improve the environment in this way, oxygen is dissolved in water pumped up from the polluted bottom of the water using the gas displacement device described above and returned to the bottom. This allows high-concentration oxygen-dissolved water to remain at the bottom, increasing the amount of dissolved oxygen at the bottom. The increased amount of dissolved oxygen activates aerobic microorganisms at the bottom, which can, for example, suppress the leaching of nutrients from sludge at the bottom into the water and reduce odors caused by the growth (decay) of blue-green algae. In other words, the abundant dissolved oxygen at the bottom of the water promotes the activity of microorganisms in the water, which then absorbs organic pollution from the microorganisms to protozoa and other organisms, and then to fish, thereby improving the environment.

[0017] Such an increase in the amount of dissolved oxygen at the bottom of the water is impossible with the aeration method. This is because, as mentioned above, with the aeration method, air bubbles (oxygen) rise to the surface rather than remaining at the bottom of the water, and because the amount of oxygen dissolved in the water is small to begin with. Furthermore, for example, when pure oxygen is supplied to water using the aeration method, there is a possibility that the bubbles (pure oxygen) may have an adverse effect on microorganisms that come into direct contact with them. On the other hand, the oxygen-dissolved water produced by the gas replacement device described above is nearly bubble-free (i.e., oxygen is contained in the water, making it difficult for the oxygen to come into direct contact with microorganisms), and therefore does not have an adverse effect on the microorganisms.

[0018] Another advantage of being bubble-free is that ozone gas can be safely dissolved in the water. Because the ozone-dissolved water produced by the gas replacement device is bubble-free, the amount of dangerous ozone gas released into the atmosphere is extremely low, making it safe to use. This ozone-dissolved water can be used, for example, for wastewater treatment.

[0019] In addition, the above-mentioned gas replacement device can dissolve various gases in water, such as nitrogen, carbon dioxide, hydrogen, or argon, in addition to ozone, so by adjusting the type and concentration of these gases, it is possible to produce gas-dissolved water for various uses. For example, oxygen-free water can be produced by dissolving nitrogen in water at a concentration close to 100%. Oxygen-free water has the advantage that it will not rust even when it comes into contact with metals such as iron, and if fish is preserved in ice made from oxygen-free water, the fish will not spoil easily (it will be easier to maintain its freshness). Furthermore, if water with dissolved carbon dioxide is given to plants such as algae and agricultural crops, photosynthesis can be promoted, which will encourage plant growth.

[0020] Furthermore, the gas replacement device described above can also generate fine bubbles by adjusting the pressure of the gas inside the container. To generate fine bubbles, the container is pressurized to a pressure higher than the pressure at which the gas dissolves 100% in water, producing gas-dissolved water in which the gas is supersaturated. When this gas-dissolved water in which the gas is supersaturated is released to the outside, fine bubbles (micro- or nanobubbles) are generated from the gas-dissolved water due to the pressure difference when the pressure returns from the pressurized state to atmospheric pressure. These fine bubbles can be used, for example, in a pressure flotation method. Furthermore, since the generation of fine bubbles using the gas replacement device described above can be achieved by simply releasing the gas-dissolved water outside the container, no special device or device is required, such as providing a nozzle at the outlet for generating fine bubbles. [Prior art documents] [Patent documents]

[0021] [Patent Document 1] International Publication No. 2017 / 191678 (e.g., paragraphs 0056-0058, Figure 1) Summary of the Invention [Problem to be solved by the invention]

[0022] However, in the above-mentioned conventional technology, the treated water flows downward in a spiral through a straightening plate installed around the air passage inside the container, and such a complex flow path is likely to create resistance to the flow of the treated water. Furthermore, for example, if the treated water is polluted water, the above-mentioned complex flow path makes it easy for the sludge contained in the polluted water to remain in the container, and the accumulation of this sludge also hinders the flow of the treated water. In other words, with the above-mentioned conventional technology, it is difficult to increase the flow rate of the treated water, and there is a problem that the processing capacity of the gas replacement device cannot be sufficiently improved.

[0023] The present invention has been made to solve the above-mentioned problems, and has an object to provide a gas replacement apparatus that can improve processing capacity. [Means for solving the problem]

[0024] In order to achieve this object, the gas replacement apparatus of the present invention comprises a gas supply means for supplying a gas, a cylindrical container whose interior is pressurized to atmospheric pressure or higher by the gas supplied from the gas supply means, a plurality of rectifying plates fixed inside the container, and treated water supply means for taking water from a water source and supplying the treated water to the container so that the treated water flows down through the plurality of rectifying plates, and the gas dissolved in the treated water is replaced with the gas supplied from the gas supply means, and the rectifying plates comprise a first rectifying plate inclined downward toward a first direction side and a second rectifying plate inclined opposite to the first direction. and a second straightening plate that slopes downward toward the direction of the flow, the first straightening plate and the second straightening plate are arranged alternately in the vertical direction, the treated water flows down in a serpentine manner between the first straightening plate and the second straightening plate, the container comprises a container body with an open upper end, a cylinder that is configured to be insertable from the upper end of the container body and is fixed to the inner peripheral side of the container body, and a lid that closes the upper end sides of the container body and the cylinder, the first straightening plate and the second straightening plate are fixed to the inner peripheral surface of the cylinder, and the vertical dimension of the cylinder is smaller than that of the container body. [Effects of the Invention]

[0025] According to the gas replacement apparatus of claim 1, the current plates include a first current plate that slopes downward toward a first direction and a second current plate that slopes downward toward a second direction opposite to the first current plate. The first current plates and the second current plates are arranged alternately in the vertical direction, so that the treated water flows downward in a meandering pattern between the first current plate and the second current plate. This type of flow path for treated water is less likely to create resistance to the downward flow of treated water than conventional technology in which treated water flows downward in a spiral around an air passage. Furthermore, for example, if the treated water is polluted, sludge (sludge) is less likely to remain in the container. This allows for a larger flow rate of treated water, which has the effect of improving the treatment capacity of the gas replacement apparatus. According to the gas replacement apparatus of claim 1, the container comprises a container body with an open upper end, a cylindrical body configured to be insertable from the upper end of the container body and fixed to the inner circumferential side of the container body, and a lid body closing the upper end sides of the container body and the cylindrical body, and the first and second current plates are fixed to the inner circumferential surface of the cylindrical body. Thus, after the cylindrical body with the first and second current plates fixed thereto is inserted and fixed into the container body, the first and second current plates can be disposed inside the container by closing the upper end sides of the container body and the cylindrical body with the lid body. That is, the first and second current plates can be fixed in advance (before being inserted into the container body) to a cylindrical body whose vertical dimension is smaller than that of the container body, which has the effect of improving the workability of the fixing operation compared to, for example, fixing the first and second current plates to the container body.

[0026] The gas replacement apparatus of claim 2 has the following effect in addition to the effect of the gas replacement apparatus of claim 1. Since convex or concave portions are formed at the downstream ends of the first and second straightening vanes, the surface area of ​​the treated water flowing down the convex or concave portions can be increased. This increases the contact area between the gas in the container and the treated water, thereby providing the effect of efficiently replacing the gas dissolved in the treated water with the gas in the container (gas supplied from the gas supply means).

[0027] The gas replacement device of claim 3 achieves the following effect in addition to the effect achieved by the gas replacement device of claim 2. Since recesses shaped to fit the convex portions of the first current rectifying plate are formed in the second current rectifying plate, the convex portions and recesses of the first current rectifying plate and the second current rectifying plate can be formed simultaneously by cutting the plate in a shape that fits the convex portions of the first current rectifying plate (the recesses of the second current rectifying plate). Therefore, there is an effect that the number of steps required to mold the first current rectifying plate and the second current rectifying plate can be reduced.

[0028] The gas replacement device according to claim 4 achieves the following effect in addition to the effect achieved by the gas replacement device according to claim 3. When the first and second current plates are butted together so that the convex portions fit into the concave portions, the outer edges of the first and second current plates become circular. As a result, by cutting a single circular plate along the shapes of the convex portions (concave portions), the first and second current plates having convex portions and concave portions can be formed simultaneously. This has the effect of reducing the material costs of the first and second current plates.

[0029] The gas replacement apparatus according to claim 5 has the following effect in addition to the effect of the gas replacement apparatus according to claim 4. Since the inclination angle of the first and second current plates with respect to a plane perpendicular to the axial direction of the container is 5° or less, it is possible to prevent an excessive gap from being generated between the semicircular outer edges of the inclined first and second current plates and the inner peripheral surface of the cylindrical container. This has the effect of allowing the outer edges of the current plates to be appropriately joined to the inner peripheral surface of the container.

[0030] According to the gas replacement apparatus of claim 6, in addition to the effects of the gas replacement apparatus of claim 1, the following effects are achieved: A drain outlet for discharging treated water to the outside of the container and a drain pipe connected to the drain outlet, and an on-off valve for opening and closing the drain pipe. is formed on the inside bottom surface of the container, so that, for example, if the treated water is polluted water, the sludge (sludge) contained in the polluted water can easily flow toward the drain outlet. This makes it possible to prevent the sludge from remaining inside the container and increase the flow rate of the treated water, which has the effect of improving the treatment capacity of the gas replacement device.

[0031] The gas replacement apparatus of claim 7 achieves the following effect in addition to the effect achieved by the gas replacement apparatus of claim 6. The bottom surface of the interior of the container is inclined downward from the inner circumferential surface side of the container toward the drain outlet side, so that sludge that has flowed down to the bottom surface side of the interior of the container can easily flow toward the drain outlet. This makes it possible to prevent sludge from remaining on the bottom surface of the container and increase the flow rate of treated water, thereby improving the treatment capacity of the gas replacement apparatus.

[0032] According to the gas replacement apparatus of claim 8, in addition to the effects of the gas replacement apparatus of claim 6 or 7, the following effects are achieved: . Exclusion The water pipes include a first drain pipe for returning the treated water to the water source and a second drain pipe for discharging the treated water to a location different from the water source. This has the effect of easily adjusting the amount of treated water returned to the water source from the first drain pipe by adjusting the flow rate of the treated water (water containing dissolved gas) discharged from the second drain pipe.

[0035] The gas replacement device of claim 9 achieves the following effect in addition to the effect achieved by the gas replacement device of claim 1. The cylindrical body is provided with a flange that protrudes radially outward from its upper end side, and the outer diameter of the flange is larger than the inner diameter of the container body. Therefore, by inserting the cylindrical body into the container body, the flange of the cylindrical body can be hooked onto the container body. This allows the upper end sides of the container body and the cylindrical body to be closed with the lid while the relative position of the cylindrical body to the container body is fixed. Therefore, there is an effect that the workability of the operation of attaching the lid can be improved. [Brief explanation of the drawings]

[0036] [Figure 1] 1 is a cross-sectional view of a gas replacement device according to an embodiment of the present invention. [Figure 2] (a) is a top view of the current plate, and (b) is a top view of the disk that is the material for the current plate. [Figure 3] FIG. 1(a) is a cross-sectional view of the cylindrical body showing the state in which the current plate has been welded, and FIG. 1(b) is a partially enlarged cross-sectional view of the gas replacement device showing how the container is assembled. DETAILED DESCRIPTION OF THE INVENTION

[0037] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. First, the configuration of a gas replacement apparatus 1 will be described with reference to Fig. 1. Fig. 1 is a cross-sectional view of a gas replacement apparatus 1 in one embodiment of the present invention. Note that Fig. 1 illustrates a cross section cut along a plane including the axis of a cylindrical container 3.

[0038] As shown in Fig. 1, the gas replacement device 1 is a device that replaces gases (e.g., nitrogen) originally dissolved in polluted water taken from a water body (water source) to be purified, such as a river or lake, with oxygen, and then returns the oxygen-dissolved water, in which the oxygen is dissolved at a high concentration, to the water body to be purified. By returning the oxygen-dissolved water to the water body to be purified, the amount of dissolved oxygen (DO) in the water body to be purified increases, and microorganisms in the water body to be purified are activated. As a result, the decomposition of organic matter in the water body to be purified is promoted, and the water quality of the water body to be purified is improved.

[0039] The gas replacement device 1 is equipped with an intake pipe 2 that takes in polluted water from the water area to be purified, and the polluted water taken in by this intake pipe 2 is supplied to the inside of the container 3. A pump (not shown) for sucking up the polluted water from the water area to be purified is connected to the intake pipe 2, and the intake pipe 2 and the pump constitute treated water supply means that supplies treated water (polluted water) to the container 3.

[0040] The container 3 comprises a cylindrical container body 30 to the side of which the water intake pipe 2 is connected, a tubular body 31 inserted into the inner periphery of the container body 30, and a lid body 32 covering the top of the tubular body 31.

[0041] A plurality of straightening plates 4a, 4b are fixed to the inner peripheral surface of the cylindrical body 31, and the polluted water supplied from the water intake pipe 2 flows downward toward the bottom of the container body 30 while being straightened by these straightening plates 4a, 4b. A supply pipe 5 for supplying oxygen to the inside of the container 3 is connected to the lid 32, and a compressor (not shown) for filling the container 3 with oxygen is connected to the supply pipe 5. The supply pipe 5 and the compressor constitute a gas supply means for supplying oxygen to the container 3.

[0042] The inside of the container 3 is pressurized to a pressure slightly higher than atmospheric pressure (for example, 0.01 to 0.1 MPa higher) by oxygen supplied from the supply pipe 5, so that gas (for example, nitrogen) dissolved in the polluted water is replaced with oxygen as the polluted water flows down the straightening plates 4a and 4b, thereby obtaining oxygen-dissolved water with a high concentration of dissolved oxygen.

[0043] The straightening plates 4a, 4b are arranged in multiple rows (two of each in this embodiment) in the vertical direction, and of these straightening plates 4a, 4b, the polluted water from the water intake pipe 2 flows into the straightening plate 4a, which is located closest to the upper end of the container 3.

[0044] The straightening vane 4a is inclined downward toward the right side (first direction side) of FIG. 1, while the straightening vane 4b is inclined downward toward the left side (second direction side). The upper surfaces of the straightening vanes 4a, 4b are flat, and these straightening vanes 4a, 4b are arranged alternately one above the other. Therefore, the polluted water flowing down the straightening vanes 4a, 4b flows in a meandering manner toward the bottom of the container 3 (see flow path A). As a result, compared to conventional technology in which polluted water flows down in a spiral around the air passage, resistance to the flow of polluted water is less likely to occur, and sludge (sludge) contained in the polluted water can be prevented from remaining in the container 3. Therefore, the flow rate of polluted water can be increased, thereby improving the treatment capacity of the gas replacement apparatus 1.

[0045] When the gas dissolved in the polluted water is replaced with oxygen, the gas (e.g., nitrogen) that was originally dissolved in the polluted water is released into the container 3. An exhaust pipe 6 for exhausting this released gas is connected to the lid 32 of the container 3. A known configuration can be used to control the exhaust from the exhaust pipe 6, and detailed description will be omitted. For example, a configuration in which the opening and closing of an on-off valve of the exhaust pipe 6 is controlled in accordance with the detection result of a sensor (not shown) that detects the oxygen concentration inside the container 3 can be exemplified (e.g., International Publication No. 2017 / 191678). The on-off valve of the exhaust pipe 6 may be opened and closed using a timer or manually.

[0046] In this way, by appropriately exhausting the gas released from the polluted water during the replacement of dissolved gas from the exhaust pipe 6, it is possible to maintain an appropriate concentration of oxygen in the container 3. This makes it possible to always obtain oxygen-dissolved water with a high concentration of dissolved oxygen.

[0047] The detailed configuration of the straightening plates 4a and 4b will be described later. The tip (downstream end) of the straightening plate 4a has a convex portion 40a (see FIG. 2) that protrudes in the downstream direction of the polluted water. Meanwhile, the tip of the straightening plate 4b has a concave portion 40b (see FIG. 2) that is recessed in the opposite direction to the downstream direction of the polluted water. This allows for a larger surface area of ​​the polluted water flowing down the convex portion 40a or the concave portion 40b compared to, for example, when the tips of the straightening plates 4a and 4b are linear. This increases the contact area between oxygen and the polluted water, allowing for efficient replacement of dissolved gases in the polluted water with oxygen. Furthermore, the formation of the convex portion 40a ensures a long distance to the tip of the straightening plate 4a, which makes it easier for the polluted water flowing down the straightening plate 4a to form a thin water film, thereby also allowing for efficient replacement of dissolved gases in the polluted water with oxygen.

[0048] A predetermined amount of oxygen-dissolved water that has flowed down the straightening plates 4a and 4b is stored on the bottom side of the container body 30. This stored amount is adjusted by a float-type water level sensor (not shown) that floats on the liquid level L of the oxygen-dissolved water, but a known adjustment method (for example, WO 2017 / 191678) can be used, so detailed explanation will be omitted.

[0049] A water level gauge 7 is fixed to the container 3, with both ends connected to the bottom of the container body 30 and the lid 32. The water level gauge 7 is made of a light-transmitting material such as glass or resin, and the amount of polluted water stored in the container 3 (the level of the liquid surface L) can be confirmed from the liquid level in this water level gauge 7.

[0050] A drain outlet 30b is formed in the bottom surface 30a of the container body 30 to discharge the oxygen-dissolved water to the outside, and a drain pipe 8 is connected to this drain outlet 30b. In order to provide the drain pipe 8 below the container body 30, the container body 30 (container 3) is supported by a plurality of legs 9 in a state spaced apart from the installation surface.

[0051] By forming the drain outlet 30b on the bottom surface 30a of the container body 30, sludge (sludge) contained in the polluted water can be more easily discharged from the drain outlet 30b than when the drain outlet 30b is formed on the inner peripheral surface 30c of the container 3, for example. This makes it possible to prevent sludge from remaining in the container 3, thereby increasing the flow rate of polluted water (oxygen-dissolved water). Therefore, the processing capacity of the gas replacement apparatus 1 can be improved.

[0052] Furthermore, when the polluted water flows down toward the bottom of the container body 30, bubbles of nitrogen originally dissolved in the polluted water and oxygen filled in the container 3 may also flow down to the bottom side of the container body 30 together with the polluted water (oxygen-dissolved water). In such cases, bubbles become mixed in the polluted water stored at the bottom of the container body 30.

[0053] In contrast, by forming the drain outlet 30b on the bottom surface 30a of the container body 30 as described above, it is possible to ensure a longer distance for air bubbles mixed in the polluted water to reach the drain outlet 30b, compared to, for example, forming the drain outlet on the inner peripheral surface 30c of the container body 30. This allows the air bubbles contained in the polluted water to rise to the liquid surface L before reaching the drain outlet 30b, thereby preventing the polluted water containing air bubbles from flowing out of the drain outlet 30b into the water area to be purified. In other words, bubble-free (non-bubble) oxygen-dissolved water can be returned to the water area to be purified.

[0054] The bottom surface 30a of the container body 30 is inclined downward from the inner peripheral surface 30c of the container body 30 toward the drain outlet 30b, so that sludge that has flowed down to the bottom surface 30a side of the container body 30 can easily flow toward the drain outlet 30b. This also makes it possible to prevent sludge from remaining on the bottom surface 30a inside the container 30.

[0055] The drain pipe 8 connected to the drain outlet 30b branches into a first drain pipe 80 and a second drain pipe 81, and these first drain pipe 80 and second drain pipe 81 are configured to be openable and closable by an opening / closing valve not shown.

[0056] Because the first drain pipe 80 connects the drain outlet 30b to the water area to be purified, the water area can be purified by the oxygen-dissolved water returned from the first drain pipe 80 to the water area to be purified. On the other hand, the second drain pipe 81 is located in a different place from the water area to be purified, for example, by connecting the drain outlet 30b to a drainage channel. This allows the polluted water to be discharged with dissolved oxygen without being directly discharged outside the water area to be purified, thereby preventing contamination of the outside of the water area to be purified. Furthermore, by adjusting the flow rate of the oxygen-dissolved water discharged from the second drain pipe 81, the amount of oxygen-dissolved water returned from the first drain pipe 80 to the water area to be purified can be adjusted.

[0057] In this way, if the first drain pipe 80 and the second drain pipe 81 are provided in advance in the gas replacement apparatus 1, the user does not need to separately prepare means (piping, etc.) for diverting such oxygen-dissolved water. In other words, by simply connecting the first drain pipe 80 or the second drain pipe 81 to a desired supply destination, the oxygen-dissolved water can be diverted and the amount of supply to the diverted destination can be adjusted, thereby improving the convenience of the gas replacement apparatus 1.

[0058] Here, the rectifying plates 4a and 4b can be fixed directly to the inner peripheral surface 30c of the container body 30, but in this configuration, the container body 30 is formed to be relatively long in the vertical direction (axial direction), and therefore it is time-consuming to fix (for example, weld) the rectifying plates 4a and 4b to the container body 30. Therefore, in this embodiment, a configuration is adopted in which the cylindrical body 31 to which the rectifying plates 4a and 4b are welded is fixed to the container body 30, and then the upper end portions thereof are covered with a lid 32. This configuration will be described with reference to Figures 2 and 3.

[0059] Fig. 2(a) is a top view of the rectifying plates 4a and 4b, and Fig. 2(b) is a top view of a disk 100 that is the material for the rectifying plates 4a and 4b. Fig. 3(a) is a cross-sectional view of the cylindrical body 31 showing the state in which the rectifying plates 4a and 4b are welded, and Fig. 3(b) is a partially enlarged cross-sectional view of the gas replacement device 1 showing the state in which the container 3 is assembled. Note that Fig. 3 shows a cross section cut at a position corresponding to Fig. 1.

[0060] When assembling the gas replacement device 1, first, semicircular straightening plates 4a and 4b are formed as shown in Fig. 2(a). As described above, convex portions 40a and concave portions 40b are formed at the tips of the straightening plates 4a and 4b, but the areas where these convex portions 40a and concave portions 40b are not formed are defined as straight line portions 41a and 41b.

[0061] The outer edge of the rectifying vane 4a, excluding the convex portions 40a and the straight portions 41a, is configured as a semicircular arc portion 42a, and the straight portions 41a extend in the normal direction to the arc portion 42a. The outer edge of the rectifying vane 4b, excluding the concave portions 40b and the straight portions 41b, is configured as a semicircular arc portion 42b, and the straight portions 41b extend in the normal direction to the arc portion 42b.

[0062] The recessed portions 40b of the current rectifying plate 4b are shaped to match the protruding portions 40a of the current rectifying plate 4a. When the protruding portions 40a are fitted into the recessed portions 40b and the tips of the current rectifying plates 4a, 4b are butted together, the outer edges of the current rectifying plates 4a, 4b along the arc portions 42a, 42b become circular. As a result, as shown in FIG. 2(b), the current rectifying plates 4a, 4b having the protruding portions 40a and the recessed portions 40b can be formed by cutting a single metal disk 100 along cutting lines 101 that match the shapes of the protruding portions 40a and the linear portions 41a of the current rectifying plate 4a. This reduces the number of steps required to form the current rectifying plates 4a, 4b and also reduces the material costs of the current rectifying plates 4a, 4b.

[0063] Furthermore, since the convex portion 40a is formed at one point on the tip of the rectifying plate 4a, the semicircular rectifying plates 4a and 4b having the convex portion 40a and the concave portion 40b can be easily formed from a single circular plate, compared to, for example, forming multiple concave and convex portions on the tips of the rectifying plates 4a and 4b.

[0064] Furthermore, the tip of the convex portion 40a is curved in a convex shape in a direction away from the arc portion 42a, and the connection portion between the base end of the convex portion 40a and the straight portion 41a is curved in a convex shape toward the arc portion 42a. That is, the convex portion 40a and the concave portion 40b at the tip of the rectifying plates 4a, 4b are formed in a smoothly curved wave shape. This makes it easier to form the semicircular rectifying plates 4a, 4b with the convex portions 40a and the concave portions 40b from a single disk 100 than, for example, when the convex portions 40a and the concave portions 40b are sawtooth (angular mountain-like).

[0065] As shown in FIG. 3(a), after forming the current plates 4a and 4b, the arc portions 42a and 42b of the current plates 4a and 4b are welded to the inner circumferential surface of the cylindrical body 31. At this time, the current plates 4a and 4b are welded while tilted with respect to a plane perpendicular to the axis of the body 31 (the left-right direction in FIG. 3(a)). However, if the tilt angle is too large (for example, an angle exceeding 5°), an excessively large gap will be formed between the arc portions 42a and 42b and the inner circumferential surface of the body 31. This is because the current plates 4a and 4b are formed by cutting a single disk 100 (see FIG. 2), and the outer diameter of the disk 100 (the curvature of the arc portions 42a and 42b) and the inner diameter of the body 31 (the curvature of the inner circumferential surface of the body 31) are the same.

[0066] Therefore, it is preferable to weld the current plates 4a and 4b to the cylindrical body 31 so that the inclination angle (the downward inclination angle) of the current plates 4a and 4b is 5° or less (3° in this embodiment) with respect to a plane perpendicular to the axis of the cylindrical body 31. Note that this angle of 5° or less is the angle of the current plates 4a and 4b with respect to the horizontal direction after the gas replacement apparatus 1 is assembled. By welding the current plates 4a and 4b to the cylindrical body 31 at such an angle, it is possible to prevent excessive gaps from being generated between the arc portions 42a and 42b of the current plates 4a and 4b and the inner circumferential surface of the cylindrical body 31. This makes it possible to easily weld the current plates 4a and 4b to the cylindrical body 31 and to prevent gaps from being generated between the current plates 4a and 4b and the inner circumferential surface of the cylindrical body 31 after welding. In other words, it is possible to appropriately weld the current plates 4a and 4b to the inner circumferential surface of the cylindrical body 31.

[0067] 3(b), after the current plates 4a and 4b are welded to the cylindrical body 31, the cylindrical body 31 is fixed to the container body 30. The container body 30 is formed in a cylindrical shape with an open upper end, and the outer diameter of the cylindrical body 31 is formed slightly smaller than the inner diameter of the container body 30. Therefore, when fixing the cylindrical body 31 to the container body 30, the cylindrical body 31 is inserted from the open portion at the upper end of the container 30.

[0068] When the cylindrical body 31 is inserted, the water intake port 30d penetrating the side surface of the container body 30 is connected to the through-hole 31a penetrating the side surface of the cylindrical body 31. The water intake port 30d and the through-hole 31a are the portions to which the above-mentioned water intake pipe 2 (see FIG. 1) is connected.

[0069] A flange 30e that protrudes radially outward is formed at the upper end of the container body 30, and a flange 31b that protrudes radially outward is also formed at the upper end of the cylindrical body 31. Because the outer diameter of the flange 31b of the cylindrical body 31 is larger than the inner diameter of the container body 30, when the cylindrical body 31 is inserted into the container body 30, the flange 31b of the cylindrical body 31 can be hooked onto the flange 30e of the container body 30. This allows the cylindrical body 31 to be fixed to the container body 30, and the lid body 32 to be fixed to the upper end sides of the container body 30 and the cylindrical body 31, to be performed while the relative position of the cylindrical body 31 to the container body 30 is determined. This improves the workability of these fixing operations.

[0070] After inserting the cylindrical body 31 into the container body 30, the open portion at the upper end of the cylindrical body 31 is covered with the lid body 32. The lid body 32 is formed in a generally hemispherical shape that is open downward, and a flange 32a protrudes radially outward from the lower end of the lid body 32. Therefore, the assembly of the container 3 is completed by overlapping the flanges 30e, 31b, and 32a of the container body 30, cylindrical body 31, and lid body 32 and fastening them together with bolts and nuts (not shown).

[0071] As described above, the container 3 of this embodiment includes a container body 30 having an open upper end, a cylindrical body 31 configured to be insertable from the upper end of the container body 30 and fixed to the inner circumferential side of the container body 30, and a lid 32 that closes the upper end sides of the container body 30 and the cylindrical body 31. The rectifying plates 4a, 4b are fixed to the inner circumferential surface of the cylindrical body 31, and therefore, by fixing the cylindrical body 31 to the container body 30, the rectifying plates 4a, 4b can be disposed on the inner circumferential side of the container body 30. In other words, the rectifying plates 4a, 4b only need to be fixed to the cylindrical body 31, which has a smaller vertical (axial) dimension than the container body 30, thereby improving the workability of the fixing operation.

[0072] Furthermore, the cylindrical body 31 has a flange 31b that protrudes radially outward from its upper end side, and the outer diameter of the flange 31b is larger than the inner diameter of the container body 30. Therefore, by inserting the cylindrical body 31 into the container body 30, the flange 31b of the cylindrical body 31 can be hooked onto the container body 30. This improves the workability of fixing the lid body 32 to the upper end sides of the cylindrical body 31 and the container body 30.

[0073] Although the present invention has been described above based on the above embodiment, the present invention is not limited to the above embodiment, and it can be easily assumed that various modifications and improvements are possible within the scope of the present invention. For example, it is naturally possible to apply the configuration of the gas replacement device described in the background art above to the gas replacement device 1 of the above embodiment.

[0074] In the above embodiment, the case where the water intake pipe 2 is connected to the side of the container 3 (container body 30) and polluted water flows in along the extension direction of the straightening plate 4a (left-right direction in FIG. 1 ) has been described, but this is not necessarily limited to this. For example, the water intake pipe 2 may be connected to the top surface (lid body 32) of the container 3, so that polluted water flows (falls) approximately vertically toward the top surface of the straightening plate 4a (convex portion 40a). With this configuration, the straightening plate 4a (convex portion 40a) can receive the polluted water flowing down from the water intake pipe 2, and the straightening plate 4a (convex portion 40a) can reliably perform its function of breaking the polluted water into a thin water film.

[0075] In the above embodiment, the wavy convex portion 40a and concave portion 40b are formed at one location on the tip of the current rectifying plate 4a, 4b. However, this is not necessarily limited to this. For example, multiple convex portions 40a and concave portions 40b may be formed at the tip of the current rectifying plate 4a, 4b, or the convex portions 40a and concave portions 40b may be formed in a sawtooth shape. Furthermore, the convex portion 40a or concave portion 40b may be formed on only one side of the current rectifying plate 4a, 4b. Alternatively, the convex portion 40a and concave portion 40b of the current rectifying plate 4a, 4b may be omitted, and the tip of the current rectifying plate 4a, 4b may be composed of only linear portions 41a, 41b.

[0076] In the above embodiment, the convex portions 40a of the current rectifying plate 4a are shaped to fit the concave portions 40b of the current rectifying plate 4b, and the current rectifying plates 4a, 4b are formed from a single disk 100. However, this is not necessarily limited to this. For example, the current rectifying plates 4a, 4b may each have convex portions 40a (concave portions 40b) of the same shape. Furthermore, the current rectifying plates 4a, 4b may not form a single disk when their tips are butted together so that their concave and convex portions fit together, or they may not fit together. In other words, the current rectifying plates 4a, 4b are not limited to being formed from a single disk 100.

[0077] Furthermore, instead of forming the rectifying plates 4a, 4b from a single disk 100, the rectifying plates 4a, 4b may be cut out from a metal plate that is larger than the disk 100. Even in this configuration, it is preferable that at least the convex portions 40a of the rectifying plates 4a, 4b have a shape that conforms to the concave portions 40b. This allows the convex portions 40a and concave portions 40b of the rectifying plates 4a, 4b to be formed simultaneously by cutting the metal plate along the shape of the convex portions 40a (concave portions 40b), thereby reducing the number of steps required to form the rectifying plates 4a, 4b.

[0078] In the above embodiment, the inclination angle of each of the current rectifying plates 4a and 4b with respect to the horizontal direction is 3° (5° or less), but this is not necessarily limited to this. For example, the current rectifying plates 4a and 4b may have an angle with respect to the horizontal direction that exceeds 5°, or may be parallel to the horizontal direction. Furthermore, the angle of the current rectifying plate 4a with respect to the horizontal direction may be larger (smaller) than the angle of the current rectifying plate 4b.

[0079] In the above embodiment, the case where the current plates 4a, 4b are joined to the inner peripheral surface of the cylindrical body 31 by welding has been described, but this is not necessarily limited to this. For example, the current plates 4a, 4b may be joined to the inner peripheral surface of the cylindrical body 31 by known fastening means such as bolts or rivets. Even in such a configuration, it is preferable to set the inclination angle of the current plates 4a, 4b with respect to the horizontal direction to 3° (5° or less). This makes it possible to prevent gaps from occurring between the cylindrical body 31 and the current plates 4a, 4b, thereby enabling them to be joined appropriately (this makes it possible to prevent gaps from occurring between the cylindrical body 31 and the current plates 4a, 4b after joining).

[0080] In the above embodiment, the container 3 is composed of the container body 30, the cylindrical body 31, and the lid body 32, and the flow straightening plates 4a and 4b are fixed to the inner circumferential surface of the cylindrical body 31. However, this is not necessarily limited to this. For example, the cylindrical body 31 may be omitted, and the flow straightening plates 4a and 4b may be fixed directly to the inner circumferential surface 30c of the container body 30, or the cylindrical body 31 and the lid body 32 may be integral with each other.

[0081] In the above embodiment, the flanges 30e, 31b, and 32a of the container body 30, the cylindrical body 31, and the lid 32 are fastened together with bolts and nuts, but this is not necessarily limited to this. For example, the flange 31b of the cylindrical body 31 may be omitted, and a metal fitting for hooking the cylindrical body 31 may be provided on the inner circumferential surface 30c of the container body 30. Furthermore, the cylindrical body 31 may be welded to the inner circumferential surface 30c of the container body 30 without using such a metal fitting for hooking the cylindrical body 31. In other words, as long as the cylindrical body 31 can be fixed to the inner circumferential side of the container body 30, the fixing method is not limited to the above embodiment.

[0082] In the above embodiment, the drain outlet 30b is formed in the bottom surface 30a of the container body 30, and the bottom surface 30a is inclined downward from the inner circumferential surface 30c of the container body 30 toward the drain outlet 30b, but this is not necessarily limited to this. For example, the drain outlet 30b may be formed in the inner circumferential surface 30c (side surface) of the container body 30, or the bottom surface 30a of the container body 30 may be configured to be parallel to the horizontal direction.

[0083] In the above embodiment, the gas supplied from the supply pipe 5 (gas supply means) to the container 3 is oxygen, but this is not necessarily limited to this. For example, other gases such as nitrogen, carbon dioxide, hydrogen, ozone, or argon may be supplied from the supply pipe 5.

[0084] In the above embodiment, the drain pipe 8 is described as including a first drain pipe 80 for returning oxygen-dissolved water to the water area to be purified, and a second drain pipe 81 for discharging the oxygen-dissolved water to a location (drainage channel) different from the water area to be purified, but this is not necessarily limited to this. For example, the drain pipe 8 may be composed of only the first drain pipe 80, or may be configured to include another drain pipe in addition to the drain pipes 80 and 81. [Explanation of symbols]

[0085] 1 Gas exchange device 2. Intake pipe (treated water supply means) 3 containers 30 Container body 30a bottom 30b Drain port 30c Inner surface 31 Cylinder 31b flange 32 Lid 4a Rectifier plate (1st rectifier plate) 40a convex part 4b Rectifier plate (second rectifier plate) 40b recess 5. Supply pipe (gas supply means) 8 Drain pipe 80 1st drain pipe 81 2nd drain pipe

Claims

1. A gas replacement apparatus comprising: a gas supply means for supplying a gas; a cylindrical container whose interior is pressurized to atmospheric pressure or higher by the gas supplied from the gas supply means; a plurality of straightening vanes fixed inside the container; and treated water supply means for taking treated water from a water source and supplying the treated water to the container so that the treated water flows down through the plurality of straightening vanes, wherein the gas replacement apparatus replaces gas dissolved in the treated water with gas supplied from the gas supply means, the current vane includes a first current vane inclined downward toward a first direction side and a second current vane inclined downward toward a second direction side opposite to the first direction, The first straightening plates and the second straightening plates are arranged alternately in the vertical direction, and the treated water flows down while meandering through the first straightening plates and the second straightening plates, The container includes a container body having an open upper end, a cylindrical body configured to be insertable from the upper end of the container body and fixed to the inner circumferential side of the container body, and a lid body that closes the upper end sides of the container body and the cylindrical body, the first and second flow straightening plates are fixed to an inner circumferential surface of the cylindrical body, A gas replacement device characterized in that the vertical dimension of the cylindrical body is smaller than that of the container body.

2. 2. The gas replacement apparatus according to claim 1, wherein the first and second flow straightening plates each have a convex portion or a concave portion formed at an end portion on the downstream side thereof.

3. the first current plate includes the protrusion, 3. The gas replacement apparatus according to claim 2, wherein the second rectifying plate has the recessed portion shaped to fit the convex portion.

4. 4. The gas replacement apparatus according to claim 3, wherein when the first and second straightening plates are butted together so that the convex portions fit into the concave portions, the outer edges of the first and second straightening plates become circular.

5. 5. A gas replacement apparatus according to claim 4, wherein the inclination angle of the first and second straightening plates with respect to a plane perpendicular to the axial direction of the container is 5[deg.] or less.

6. 2. The gas replacement apparatus according to claim 1, further comprising: a drain outlet formed on the bottom surface of the inside of the container for discharging the treated water to the outside of the container; a drain pipe connected to the drain outlet; and an on-off valve for opening and closing the drain pipe.

7. 7. A gas replacement apparatus according to claim 6, wherein the bottom surface of the inside of the container is inclined downward from the inner circumferential surface side of the container toward the drain outlet side.

8. A gas replacement device as described in Claim 6 or 7, characterized in that the drain pipe comprises a first drain pipe for returning the treated water to the water source, and a second drain pipe for discharging the treated water to a location different from the water source.

9. The cylindrical body has a flange extending radially outward from an upper end side thereof, 2. A gas replacement apparatus according to claim 1, wherein the outer diameter of the flange is larger than the inner diameter of the container body.

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