Liquid treatment device

Abstract

Provided is a liquid treatment device having a simple configuration.　The liquid treatment device comprises: a tank which stores a liquid to be treated; a flow path through which the liquid to be treated flowing out of the tank flows and through which the liquid to be treated is recirculated to the tank; a pump which is provided in the flow path and which causes the liquid to be treated to flow out from the tank into the flow path; and a fluid suction unit which is provided on the upstream side of the pump in the flow path and which mixes a mixture fluid, which is a fluid different from the liquid to be treated, with the liquid to be treated. The fluid suction unit has a nozzle, a diffuser, and a suction chamber, and a supply port communicating with the nozzle and a discharge port communicating with the diffuser are provided in the flow path, wherein, when the liquid to be treated passes through the nozzle, the suction chamber and the diffuser, the mixture fluid is sucked into the suction chamber from a suction port, which is an inlet to the suction chamber. The inner diameter of the nozzle is set such that the flow velocity of the liquid to be treated is 5 m / sec or more and 6 m / sec or less.

Description

Liquid Treatment Equipment

[0001] The present invention relates to a liquid treatment device.

[0002] Patent Document 1 discloses an open-system continuous pressurized flow-type hydrogen gas-dissolved liquid production apparatus including a liquid flow conduit for flowing a raw liquid to a gas-dissolved liquid receiver, a pressurizing means provided in the liquid flow conduit for pressurizing the raw liquid and circulating it through the conduit, at least one gas-liquid mixing section provided in the liquid flow conduit, connected to a gas container via a gas supply pipe for mixing hydrogen gas from the gas container into the liquid, and at least one static mixer provided in the liquid flow conduit downstream of the gas-liquid mixing section for maintaining the pressure of the gas-mixed liquid mixed in the gas-liquid mixing section and promoting dissolution of the gas into the liquid. In this open-system continuous pressurized flow-type hydrogen gas-dissolved liquid production apparatus, the liquid is circulated through the liquid flow conduit at a flow rate of 10 to 40 L / min and pressurized to continuously produce hydrogen gas-dissolved liquid.

[0003] Utility Model Registration No. 3139460

[0004] In the invention described in Patent Document 1, the fluids are mixed by passing through the static mixer only once, which may result in poor mixing performance. Furthermore, because the invention described in Patent Document 1 mixes the fluids by passing through the static mixer only once, a large static mixer is required to improve mixing performance, which requires a considerable amount of space for installing the equipment.

[0005] The present invention has been made in consideration of these circumstances, and aims to provide a liquid treatment device that can efficiently mix two types of fluids (liquid and gas, or liquid and liquid) in a space-saving manner.

[0006] In order to solve the above problems, a liquid treatment device according to the present invention includes, for example, a tank for storing a liquid to be treated, a flow path through which the liquid to be treated flowing out of the tank flows and through which the liquid to be treated is returned to the tank, a pump provided in the flow path and causing the liquid to be treated to flow from the tank into the flow path, and a fluid suction unit provided in the flow path upstream of the pump and mixing the liquid to be treated with a mixed fluid that is a fluid different from the liquid to be treated, wherein the fluid suction unit has a nozzle, a diffuser, and a suction chamber, and a supply port communicating with the nozzle and a discharge port communicating with the diffuser are provided in the flow path, and the liquid to be treated passes through the nozzle, the suction chamber, and the diffuser, so that the mixed fluid is sucked into the suction chamber from the suction port, which is an inlet to the suction chamber, and the inner diameter of the nozzle is set so that the flow velocity of the liquid to be treated is 5 m / s or more and 6 m / s or less.

[0007] In the liquid treatment device according to the present invention, a fluid intake section and a pump are provided in the flow path, and by flowing the liquid to be treated through the fluid intake section, a mixed fluid is drawn into the fluid intake section (suction chamber). Therefore, two types of fluid (here, water as the liquid to be treated and air as the mixed fluid) can be efficiently mixed using only the fluid intake section. Furthermore, if the flow path is a fluid circulation circuit, the same liquid to be treated can be treated multiple times through the fluid intake section, allowing the mixed fluid to be efficiently mixed into the liquid to be treated. In this way, two types of fluid can be efficiently mixed using a space-saving and simple configuration.

[0008] The flow path may further include a dissolving tank provided downstream of the pump, which dissolves the mixed fluid under a pressurized environment after the mixed fluid and the liquid to be treated are mixed. This allows the mixed fluid to be efficiently dissolved in the dissolving tank. Furthermore, even when a fluid circulation circuit is not used, the mixed fluid passes through the dissolving tank, improving mixing efficiency.

[0009] The mixing unit may include a mixing section provided in the flow path downstream of the pump and upstream of the dissolving tank, for mixing the mixed fluid with the liquid to be treated, the mixing section including a casing having a cylindrical side surface provided in the flow path and a plurality of plate-like members provided inside the casing, the plate-like members each having a plurality of first through holes through which the liquid to be treated passes, the plurality of plate-like members being stacked such that the first through hole of a first plate-like member among the plurality of plate-like members partially overlaps with the first through hole of a second plate-like member adjacent to the first plate-like member, thereby enabling efficient mixing of two types of fluids.

[0010] In order to solve the above problems, a liquid treatment apparatus according to the present invention includes, for example, a tank for storing a liquid to be treated, a flow path through which the liquid to be treated flowing out of the tank flows and through which the liquid to be treated returns to the tank, a pump provided in the flow path and causing the liquid to be treated to flow out of the tank into the flow path, a fluid inlet portion provided on the flow path downstream of the pump, the fluid inlet portion having a gas tank filled with high-pressure gas that is a mixed fluid, and a connecting portion connecting the gas tank and the flow path, and a mixing section provided downstream of the mixing section for mixing the mixed fluid with the liquid to be treated, wherein the mixing section has a casing with a cylindrical side provided in the flow path and a plurality of plate-like members provided inside the casing, wherein the plate-like members are provided with a plurality of first through holes through which the liquid to be treated passes, and the plurality of plate-like members are stacked such that the first through hole of a first plate-like member among the plurality of plate-like members partially overlaps with the first through hole of a second plate-like member adjacent to the first plate-like member.

[0011] In the liquid treatment device according to the present invention, a pump, a fluid intake section, and a mixing section are provided in the flow path, and by flowing the liquid to be treated and the mixed fluid through the mixing section, two types of fluid (here, water as the liquid to be treated and air as the mixed fluid) can be efficiently mixed. Furthermore, when the flow path is a fluid circulation circuit, the same liquid to be treated can be treated multiple times through the fluid intake section, and the mixed fluid can be efficiently mixed into the liquid to be treated. In this way, a space-saving liquid treatment device can be achieved.

[0012] The system may further include a dissolving tank provided downstream of the mixing section of the flow path, for dissolving the mixed fluid of the liquid to be treated and the mixed fluid under a pressurized environment. This allows the mixed fluid to be efficiently dissolved in the liquid to be treated within the dissolving tank. Furthermore, even when a fluid circulation circuit is not used, the mixed fluid passes through the dissolving tank, thereby improving mixing efficiency.

[0013] The casing may have a first end provided with a third inlet port that is an inlet for the liquid to be treated and a second end provided with a second outlet port that is an outlet for the liquid to be treated, at both ends of the side surface, the plate-like member abutting the first end but not abutting the second end port or the side surface, and the end of the stacked plate-like members that is not abutting the first end port may be covered by a third plate-like member. This allows the mixed fluid to be mixed with the liquid to be treated more effectively.

[0014] The liquid to be treated may be water, and the mixed fluid may be at least one of air, carbon dioxide, and nitrogen. The pump may be a positive displacement pump, and the liquid to be treated may be a non-Newtonian fluid. By using a positive displacement pump, a highly viscous fluid can be treated as the liquid to be treated. The pump may be a centrifugal pump, and the liquid to be treated may be a Newtonian fluid. In the case of a Newtonian fluid, a centrifugal pump can be used, which is small, lightweight, and usable for a wide range of applications (water volume, head, etc.).

[0015] According to the present invention, two types of fluids (liquid and gas, or liquid and liquid) can be efficiently mixed with a simple configuration.

[0016] 1 is a schematic diagram showing an example of a liquid treatment device 1. FIG. 1 is a cross-sectional view showing an outline of a fluid suction section 12. FIG. 2 is a graph comparing the amount of mixed fluid (air) mixed into a liquid to be treated (water) with and without a fluid suction section 12. FIG. 3 is a schematic diagram showing an example of a liquid treatment device 2. FIG. 4 is a diagram showing an outline of a mixing section 15, and FIG. 5 is a diagram showing an outline of a plate-shaped member 15b. FIG. 4 is a partial enlarged view of a plate-shaped member 15b, and FIG. 5 is a partial enlarged view of a plate-shaped member 15c. FIG. 5 is a diagram showing plate-shaped members 15b and 15c stacked alternately. FIG. 6 is a graph comparing the amount of mixed fluid (air) mixed into a liquid to be treated (water) with and without a fluid suction section 12 and a mixing section 15. FIG. 7 is a graph comparing the amount of mixed fluid (air) mixed into a liquid to be treated (water) with and without a fluid suction section 12 and a mixing section 15. FIG. 8 is a schematic diagram showing an example of a liquid treatment device 2A having a mixing section 15A according to a modified example. FIG. 9 is a diagram showing an outline of a mixing section 15A. 1 is a graph comparing the amount of mixed fluid (air) mixed into the liquid to be treated (water) due to the difference between mixing section 15 and mixing section 15A. FIG. 2 is a schematic diagram showing an example of a liquid treatment device 3. FIG. 3 is a graph comparing the amount of mixed fluid (carbon dioxide) mixed into the liquid to be treated (water) due to the presence or absence of mixing section 15. FIG. 4 is a graph comparing the amount of mixed fluid (nitrogen) mixed into the liquid to be treated (water) due to the presence or absence of mixing section 15, (B) being an enlarged portion of (A). FIG. 5 is a diagram schematically showing a dissolved air amount measuring device 100.

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A liquid treatment apparatus according to an embodiment of the present invention is an apparatus for mixing a fluid into a liquid to be treated and removing gas contained in the liquid to be treated.

[0018] 1 is a schematic diagram showing an example of a liquid treatment device 1 according to a first embodiment of the present invention. The liquid treatment device 1 mainly includes a tank 11, a fluid suction unit 12, a pump 13, a dissolving tank 16, a flow rate control valve 14, and a flow path 20.

[0019] The tank 11 is a container for storing the liquid to be treated. In this embodiment, water is used as the liquid to be treated, but various liquids other than water can be used as the liquid to be treated.

[0020] The tank 11 is provided with an outlet 111. The outlet 111 is connected to a flow path 20.

[0021] The flow path 20 includes pipes, hoses, joints, etc. through which a fluid (liquid, gas) flows. The flow path 20 constitutes a fluid circulation circuit through which the liquid to be treated flowing out of the tank 11 flows and which returns the liquid to be treated to the tank 11. The flow path 20 is provided with a fluid intake unit 12, a pump 13, a dissolving tank 16, and a flow rate adjustment valve 14.

[0022] The fluid suction unit 12 is a component that mixes a fluid with the liquid to be treated, and is provided upstream of the pump 13. Figure 2 is a cross-sectional view showing an outline of the fluid suction unit 12. The fluid suction unit 12 is cylindrical, and mainly has a first housing 121, a second housing 122, and a third housing 123.

[0023] The first housing 121 has a supply port 121a for the liquid to be treated. A nozzle 121b is provided on the opposite side of the supply port 121a of the first housing 121. The supply port 121a is in communication with the nozzle 121b, and the supply port 121a is provided with an upstream portion 21a of the outflow path 21. The nozzle 121b is formed so as to taper in the flow direction of the liquid to be treated.

[0024] The nozzle 121b of the present invention is characterized in that the inner diameter d of the nozzle 121b is set so that the flow rate is 5 m / s or more and 6 m / s or less, without abruptly narrowing the inner diameter. For example, when the flow rate of the liquid to be treated is 100 L / min, the inner diameter d of the nozzle 121b is 18.8 mm or more and 20.6 mm or less. In this way, by widening the inner diameter of the nozzle 121b, the negative pressure can be reduced and an appropriate suction pressure (negative pressure of -0.02 MPa to -0.03 MPa) can be achieved.

[0025] The third housing 123 has an outlet 123a for the liquid to be treated, a contracting section 123b whose cross section gradually decreases, and a diffuser 123c whose cross section gradually increases. Note that the contracting section 123b is not essential. The outlet 123a is connected to the contracting section 123b and the diffuser 123c, and the outlet 123a is provided with a downstream section 21b of the outflow path 21.

[0026] The second housing 122 is provided between the first housing 121 and the third housing 123 and has an inlet 122a. The interior of the second housing 122 is an inlet chamber 122b. A fluid to be mixed with the liquid to be treated (a mixed fluid) is drawn into the inlet chamber 122b from the inlet 122a. In this embodiment, the inlet 122a is open to the atmosphere, and air flows into the inlet chamber 122b from the inlet 122a as the mixed fluid.

[0027] The liquid to be treated is supplied as a driving fluid from the supply port 121a and discharged from the discharge port 123a. The liquid to be treated flows into the third housing 123 at an increased flow rate in the nozzle 121b, which reduces the pressure in the suction chamber 122b and causes the mixed fluid (here, air) to be sucked into the suction chamber 122b.

[0028] Returning to the explanation of FIG. 1 , the pump 13 is provided downstream of the fluid suction section 12. Because the pump 13 is provided downstream of the fluid suction section 12, there is no need to worry about the pressure during pumping (suctioning fluid). The downstream side of the pump 13 is pressurized, making it difficult to stably control the amount of air under pressure. However, the upstream side of the pump 13 is generally less affected by pressure, so the suction force can be adjusted solely by the nozzle diameter of the fluid suction section 12. The upstream side of the pump 13 in the flow path 20 is the outflow path 21, and the downstream side is the return path 22. The pump 13 flows the treated liquid from the tank 11 to the outflow path 21 and returns the treated liquid to the tank 11 via the return path 22. A centrifugal pump (such as a cascade pump or a centrifugal pump) or a positive displacement pump can be used for the pump 13. In this embodiment, a centrifugal pump is used for the pump 13.

[0029] The dissolving tank 16 is located downstream of the pump 13. The dissolving tank 16 is pressurized to a pressure equal to or greater than atmospheric pressure (e.g., 0.3 MPa or higher), and dissolves the mixed fluid in a pressurized environment. This dissolves the mixed fluid in the dissolving tank 16. The dissolving tank 16 desirably has a volume sufficient to allow the two fluids to mix. The dissolving ratio in the dissolving tank 16 is increased by retaining the liquid in the dissolving tank 16 for approximately 5 seconds or more and approximately 24 seconds or less (see Tables 1 and 2). Therefore, for example, it is desirable to set the inflow velocity of the fluid into the dissolving tank 16 to approximately 2 m / s or more, and the height of the dissolving tank 16 to be between two and five times the inner diameter (see Tables 1 to 3).

[0030] Table 1 shows the relationship between the shape of the dissolving tank 16 and the dissolution ratio, Table 2 shows the relationship between the shape of the dissolving tank 16 and the fluid residence time in the dissolving tank, and Table 3 shows the relationship between the shape of the dissolving tank 16 and the inflow rate. In Tables 1 to 3, the dissolving tank 16 with an internal capacity of 3.7 L has an inner diameter of 100 mm and a height of 450 mm, while the dissolving tank 16 with an internal capacity of 7.8 L has an inner diameter of 110 mm and a height of 450 mm. In Tables 1 to 3, the diameters of the jet nozzles at the inlet of the dissolving tank 16 are 12.7 mm for 10A, 16.1 mm for 15A, 21.6 mm for 20A, and 27.6 mm for 25A, respectively. Tables 1 to 3 show the results when the flow rate of the liquid flowing into the dissolution tank 16 from the inlet was set to 20 L / min, 30 L / min, 40 L / min, 50 L / min, 60 L / min, and 70 L / min.

[0031] It is also desirable to have a boundary layer between the liquid and the gas within the dissolving tank 16. For example, a bowl-shaped plate-like member can be provided within the dissolving tank 16 to generate a turbulent bubble vortex within the dissolving tank 16. Alternatively, a turbulent bubble vortex can be generated within the dissolving tank 16 by increasing the flow rate of the liquid flowing into the dissolving tank 16. The presence of a boundary layer allows the gas to be sufficiently dissolved within the dissolving tank 16, and undissolved gas is not discharged from the dissolving tank 16. This minimizes gas consumption. If undissolved gas were discharged, the only way to increase the dissolution ratio would be to increase the amount of gas injected, which would increase gas consumption. However, when the dissolution ratio in the dissolving tank 16 is high, the amount of gas injected can be reduced, thereby reducing gas consumption.

[0032] The flow rate control valve 14 is provided downstream of the dissolution tank 16. Here, the upstream side of the dissolution tank 16 of the flow path 20 is referred to as an upstream section 22a, and the downstream side of the flow rate control valve 14 is referred to as a downstream section 22b. A pressure gauge may be provided in the upstream section 22a, and a flow meter may be provided in the downstream section 22b.

[0033] The dissolving tank 16 is not essential. When the mixed fluid is a gas, the mixed fluid will dissolve in the liquid to be treated without the dissolving tank 16, but it is desirable to provide the dissolving tank 16 for efficient dissolution. Also, when both the liquid to be treated and the mixed fluid are liquids, the dissolving tank 16 is not necessary. When the dissolving tank 16 is provided, the flow rate adjustment valve 14 is installed downstream of the dissolving tank 16.

[0034] Next, the operation of the liquid treatment device 1 will be described. When the pump 13 is driven, the liquid to be treated (here, water) flows from the tank 11 into the flow path 20. The liquid to be treated that has flowed into the upstream section 21a passes through the fluid suction section 12 and flows into the downstream section 21b. In the fluid suction section 12, the liquid to be treated flows sequentially through the hollow section of the first housing 121, the hollow section (suction chamber 122b) of the second housing 122, and the hollow section of the third housing 123. This flow of the liquid to be treated causes a mixed fluid (here, air) to flow into the suction chamber 122b via the suction port 122a. In the suction chamber 122b, the liquid to be treated and the mixed fluid are mixed, and the resulting mixed liquid flows into the diffuser 123c. In the diffuser 123c, the fluid flows from a low-pressure side to a high-pressure side, which makes boundary layers more likely to separate, making the flow of the mixed liquid of the liquid to be treated and the mixed fluid unstable. As a result, the mixed fluid turns into fine bubbles, and the fine bubbles are mixed into the liquid to be treated.

[0035] In liquid treatment device 1, flow path 20 constitutes a fluid circulation circuit, and the mixed liquid treated in fluid intake unit 12 is pressurized and dissolved in dissolving tank 16, returned to atmospheric pressure, returned to tank 11, and then flows through flow path 20 again to be treated in fluid intake unit 12. In the case of a fluid circulation circuit, the same liquid to be treated can be treated multiple times in fluid intake unit 12, and the mixed fluid can be efficiently mixed into the liquid to be treated. Even in the case of not using a fluid circulation circuit, the mixed liquid passes through dissolving tank 16, improving mixing efficiency.

[0036] Figure 3 is a graph comparing the amount of mixed fluid (air) mixed into the liquid to be treated (water) with and without the fluid suction section 12. In Figure 3, the dotted line shows the air dissolution ratio (described in detail later) in the case of only the pump 13 (without the fluid suction section 12), and the solid line shows the air dissolution ratio in the case of the fluid suction section 12 and the pump 13. The dissolution ratio is an index expressed as the ratio between the amount of dissolved air, which is the amount of fine bubbles when released to the atmosphere, and the amount of saturated air; it can be seen that the higher the dissolution ratio, the more gas is dissolved in the liquid to be treated.

[0037] In FIG. 3 , the vertical axis represents the dissolution ratio (%), and the horizontal axis represents the air injection rate (NL / min). NL stands for normal liters. The air injection rate is the amount of air injected into the treated liquid, and can also be expressed as the ratio (%) of the air injection rate to the amount of treated liquid passing through the pump 13 (the discharge rate of the pump 13). For example, in FIG. 3 , the ratio is 0.9% when the air injection rate is 5 NL / min, 1.9% when the air injection rate is 10 NL / min, 2.8% when the air injection rate is 15 NL / min, 3.8% when the air injection rate is 20 NL / min, 4.8% when the air injection rate is 25 NL / min, and 6.6% when the air injection rate is 35 NL / min.

[0038] As shown in Figure 3, it can be seen that a larger amount of gas (here, air) is dissolved in the liquid to be treated (here, water) in the liquid treatment device 1 of this embodiment, which is provided with the fluid suction unit 12 and the pump 13, compared to the case where only the pump 13 is provided. Note that the discharge pressure of the pump 13 in Figure 3 is the same as the pressure in the dissolution tank 16, 0.5 MPa. Note that the flow rate of the pump 13 is omitted here because it varies depending on the amount of air injected.

[0039] The dissolution ratio will now be described. Fig. 15 is a diagram showing a schematic diagram of a method for measuring the amount of dissolved air. The dissolved air amount measuring device 100 mainly includes a dissolution tank 16, flow paths 20 and 106, an air reservoir 103, a water reservoir 104, and a pressure release valve 105.

[0040] Flow path 102 is connected to flow path 20 downstream of dissolving tank 16 provided in flow path 20 of liquid treatment device 1. First, the liquid to be treated flowing through flow path 20 is pressurized and dissolved in dissolving tank 16, separating and removing large undissolved air bubbles, and the liquid to be treated from which the undissolved air bubbles have been separated and removed is allowed to flow through flow path 102. Next, the liquid to be treated flowing through flow path 102 is depressurized to atmospheric pressure by pressure release valve 105 and released into air reservoir 103. Air bubbles are separated from the liquid to be treated in air reservoir 103, and the air bubbles float and accumulate at the top of air reservoir 103, while the liquid to be treated accumulates in water tank 104 connected by flow path 106. The pressure release valve 105 adjusts the amount (speed) of the liquid to be treated released so that air bubbles do not flow into water reservoir 104.

[0041] When 1 L of the liquid to be treated has accumulated in the water tank 104, the amount of air in the air tank 103 is measured. The amount of air in the air tank 103 is the amount of air that has separated out from 1 L of the liquid to be treated, i.e., the amount of dissolved air. These measurements are made using scales provided on the transparent air tank 103 and the water tank 104.

[0042] Since the amount of dissolved air is affected by factors such as water temperature, the amount of air separated from the treated liquid is converted into a dissolution ratio based on the water temperature at the time of measurement. The dissolution ratio is expressed as the ratio of the amount of dissolved air to the amount of saturated air at the temperature at which the amount of dissolved air was measured, as shown in Equation (1).

[0043] According to this embodiment, two types of fluids (here, water as the liquid to be treated and air as the mixed fluid) can be efficiently mixed using only fluid intake section 12. In particular, since dissolution is performed under pressure in dissolving tank 16, the mixed fluid can be efficiently dissolved in the liquid to be treated. Therefore, the configuration of liquid treatment device 1 can be simplified.

[0044] Furthermore, according to this embodiment, when the flow path 20 is a fluid circulation circuit, the same liquid to be treated can be treated multiple times in the fluid intake section 12, and the mixed fluid can be efficiently mixed into the liquid to be treated.

[0045] Furthermore, according to this embodiment, by setting the inner diameter of the nozzle 121b so that the flow velocity of the liquid to be treated is 5 m / s or more and 6 m / s or less, the negative pressure can be reduced and the mixed fluid can be sucked in at an appropriate suction pressure (negative pressure of -0.02 MPa to -0.03 MPa). If the suction force of the mixed fluid is too low, the amount of the mixed fluid sucked in decreases, resulting in a poor dissolution ratio. Furthermore, if the suction force of the mixed fluid is too high, depending on the type of pump 13 (for example, in the case of a centrifugal pump), the pump 13 itself may cause an airlock (the pump 13 cannot pump water) in relation to the amount of mixed fluid sucked in. Therefore, by adjusting the flow velocity of the liquid to be treated to an appropriate value, the suction force of the mixed fluid can be adjusted, allowing the mixed fluid to be efficiently mixed into the liquid to be treated.

[0046] In this embodiment, air is supplied as a mixed fluid to the fluid intake section 12 and the air is dissolved in the water, which is the liquid to be treated, but the gas is not limited to air. For example, gases such as carbon dioxide or nitrogen may be supplied to the fluid intake section 12 and these gases may be dissolved in the liquid to be treated, or the air in the liquid to be treated may be replaced with carbon dioxide, nitrogen, or the like.

[0047] Furthermore, in this embodiment, the mixed fluid is not limited to gas. For example, the mixed fluid may be a liquid. For example, the liquid to be treated may be water, the mixed fluid may be oil, and the oil may be dissolved in the water. Although water and oil do not easily mix, by using the liquid treatment device 1, it is possible to mix finely divided oil particles into the water.

[0048] Furthermore, in this embodiment, the liquid to be treated is water, but the liquid to be treated is not limited to water. For example, the liquid to be treated may be oil. The liquid to be treated may also be a non-Newtonian fluid. For example, in the case where the liquid to be treated is mayonnaise, which is a non-Newtonian fluid, the mixed fluid can be nitrogen and the oxygen in the mayonnaise can be replaced with nitrogen using the liquid treatment device 1, thereby improving the shelf life of the mayonnaise. Furthermore, in the case where the liquid to be treated is a dairy product such as milk, oxidation can be prevented by replacing the oxygen contained in the dairy product with nitrogen.

[0049] Second Embodiment In the first embodiment of the present invention, a fluid is mixed into the liquid to be treated using the fluid suction unit 12, but the method of mixing a fluid into the liquid to be treated is not limited to this. A liquid treatment device 2 of the present invention will be described below. Note that the same parts as those in the first embodiment are designated by the same reference numerals, and description thereof will be omitted.

[0050] 4 is a schematic diagram showing an example of a liquid treatment device 2 according to a second embodiment of the present invention. Liquid treatment device 2 mainly includes tank 11, fluid intake section 12, pump 13, mixing section 15, dissolving tank 16, flow rate control valve 14, and flow path 20. Flow path 20 is provided with fluid intake section 12, pump 13, flow rate control valve 14, mixing section 15, and dissolving tank 16.

[0051] The mixing section 15 is a component that mixes the liquid to be treated with a fluid, and is provided downstream of the pump 13. Pressure loss occurs in the mixing section 15, and if the mixing section 15 is provided upstream of the pump 13, the mixing section 15 will create resistance, making it difficult to adjust the suction force. Therefore, the mixing section 15 is provided downstream of the pump 13.

[0052] The dissolving tank 16 is provided downstream of the mixing section 15, and the flow rate control valve 14 is provided downstream of the dissolving tank 16. The upstream side of the mixing section 15 of the flow path 20 is referred to as an upstream section 22c, the downstream side of the mixing section 15 and the upstream side of the dissolving tank 16 is referred to as a midstream section 22d, and the downstream side of the flow rate control valve 14 is referred to as a downstream section 22b. A pressure gauge may be provided in the upstream section 22c, and a flow meter may be provided in the downstream section 22b.

[0053] 5A is a diagram showing an outline of the mixing section 15. The mixing section 15 mainly includes a casing 15a and a plurality of plate-like members 15b and 15c.

[0054] The casing 15a is cylindrical and is provided in the flow path 20 (here, the return path 22). The casing 15a has a cylindrical side surface 15j, and ends 15h (corresponding to a first end of the present invention) and 15i (corresponding to a second end of the present invention) that cover both ends of the side surface 15j. One end 15h is provided with an inlet 15e through which the liquid to be treated and the fluid sucked into the fluid suction section 12 flow in, and the other end 15i is provided with an outlet 15f through which the liquid to be treated and the fluid sucked into the fluid suction section 12 flow out.

[0055] Plate-shaped members 15b and 15c are provided inside the casing 15a. In this embodiment, two plate-shaped members 15b and two plate-shaped members 15c are provided, but the number of plate-shaped members 15b and 15c is not limited to this. The plate-shaped members 15b and 15c are circular and have the same peripheral size. The plate-shaped members 15b and 15c are alternately stacked. Note that the plate-shaped members 15b and 15c are not limited to being circular, and may have a rectangular shape in a plan view (the shape when viewed along the plate thickness direction).

[0056] Plate-like members 15b and 15c are provided so as to abut against end 15h but not against end 15i. Furthermore, plate-like members 15b and 15c are provided so as not to abut against side surface 15j connecting end 15h and end 15i. Furthermore, one end of each of plate-like members 15b and 15c (the end not abutting end 15h) is covered by plate-like member 15d.

[0057] 5(B) is a schematic diagram of plate-shaped member 15b. Each plate-shaped member 15b is provided with a plurality of through-holes 15g (corresponding to first through-holes of the present invention) through which the liquid to be treated passes. The through-holes 15g are, for example, hexagonal in shape. In this embodiment, the through-holes 15g are provided on the entire surface of plate-shaped member 15b. Although not shown, plate-shaped member 15c also has a plurality of through-holes 15g (on the entire surface) similar to plate-shaped member 15b.

[0058] Fig. 6(A) is a partial enlarged view of plate-shaped member 15b (corresponding to the first plate-shaped member of the present invention), Fig. 6(B) is a partial enlarged view of plate-shaped member 15c (corresponding to the second plate-shaped member of the present invention), and Fig. 6(C) is a diagram showing the state in which plate-shaped members 15b and 15c are alternately stacked. In Fig. 6, plate-shaped member 15c is shown by a dotted line for the sake of explanation.

[0059] The difference between plate-shaped member 15b and plate-shaped member 15c is the positional relationship between the peripheries of plate-shaped members 15b and 15c and the through holes 15g (the positions of the through holes 15g). For example, the positions of the through holes 15g in plate-shaped member 15b and the positions of the through holes 15g in plate-shaped member 15c are offset by half the pitch of the through holes 15g in the horizontal direction of Fig. 6 and by a quarter pitch of the through holes 15g in the vertical direction of Fig. 6. As a result, when plate-shaped member 15b and plate-shaped member 15c are stacked so that the peripheries are aligned, the through holes 15g in plate-shaped member 15b and the through holes 15g in plate-shaped member 15c partially overlap.

[0060] Returning to the explanation of Figure 5(A), the liquid to be treated and the mixed fluid that flow in through the inlet 15e are stirred through the through-hole 15g and flow from the periphery of the plate-like members 15b and 15c into the hollow portion of the casing 15a. As a result, the flow of the fluid (the mixed liquid of the liquid to be treated and the mixed fluid) becomes unstable as it passes through the through-hole 15g, and the liquid to be treated and the mixed fluid are mixed. The mixed liquid then flows out from the outlet 15f.

[0061] Next, the operation of liquid treatment device 2 will be described with reference to Figure 4. When pump 13 is driven, the liquid to be treated (here, water) flows from tank 11 into flow path 20 (upstream section 21a), and then flows into downstream section 21b through fluid suction section 12. As the liquid to be treated flows through fluid suction section 12, air (here) flows into suction chamber 122b via suction port 122a, where the liquid to be treated and the mixed fluid are mixed, and the mixed fluid turns into fine bubbles in diffuser 123c and is mixed with the liquid to be treated.

[0062] Thereafter, the liquid to be treated, with fine bubbles mixed therein, flows into the mixing section 15 in the fluid intake section 12. The flow of the fluid (mixture of the liquid to be treated and the mixed fluid) that has flowed into the mixing section 15 becomes unstable as it passes through the through-holes 15g, and the mixed fluid that has become fine bubbles is further mixed into the liquid to be treated.

[0063] In liquid treatment device 2, flow path 20 constitutes a fluid circulation circuit, and the liquid to be treated is treated in fluid intake section 12 and mixing section 15, pressurized and dissolved in dissolving tank 16, and returned to atmospheric pressure, and then returns to tank 11, flows through flow path 20 again, and is treated in fluid intake section 12 and mixing section 15. In the case of a fluid circulation circuit, the same liquid to be treated can be treated multiple times in fluid intake section 12 and mixing section 15, and the mixed fluid can be efficiently mixed into the liquid to be treated.

[0064] FIG. 7 is a graph comparing the amount of mixed fluid (air) mixed into the treated liquid (water) with and without the fluid suction unit 12 and mixing unit 15. In FIG. 7, the dotted line shows the air dissolution ratio in the case where the pump 13, dissolving tank 16, and flow rate control valve 14 are not provided (i.e., the fluid suction unit 12 and mixing unit 15 are not provided), while the solid line shows the air dissolution ratio in the case where the fluid suction unit 12, pump 13, mixing unit 15, dissolving tank 16, and flow rate control valve 14 are provided. As shown in FIG. 7, when the fluid suction unit 12, pump 13, mixing unit 15, dissolving tank 16, and flow rate control valve 14 are provided, more air is mixed into the water than when the pump 13, dissolving tank 16, and flow rate control valve 14 are provided. Note that the discharge pressure of the pump 13 in FIG. 7 is the same as the pressure in the dissolving tank 16, 0.5 MPa.

[0065] FIG. 8 is a graph comparing the amount of mixed fluid (air) mixed into the liquid to be treated (water) with and without the mixer 15. In FIG. 8, the dotted line indicates the air dissolution ratio when the fluid suction unit 12, pump 13, dissolving tank 16, and flow rate control valve 14 are not provided (i.e., when the mixer 15 is not provided), while the solid line indicates the air dissolution ratio when the fluid suction unit 12, pump 13, mixing unit 15, dissolving tank 16, and flow rate control valve 14 are provided. As shown in FIG. 8, when the fluid suction unit 12, pump 13, mixing unit 15, dissolving tank 16, and flow rate control valve 14 are provided, more air is mixed into the water than when the pump 13, fluid suction unit 12, dissolving tank 16, and flow rate control valve 14 are provided. Note that the discharge pressure of the pump 13 in FIG. 8 is the same as the pressure in the dissolving tank 16, 0.3 MPa.

[0066] According to this embodiment, two types of fluids can be efficiently mixed by providing the fluid suction section 12 and the mixing section 15. In particular, since dissolution is performed under pressure in the dissolving tank 16, the mixed fluid can be efficiently dissolved in the liquid to be treated.

[0067] Furthermore, according to this embodiment, when the flow path 20 is a fluid circulation circuit, the same liquid to be treated can be treated multiple times in the fluid intake section 12 and the mixing section 15, and the mixed fluid can be efficiently mixed into the liquid to be treated.

[0068] In the present embodiment, the through-holes 15g are hexagonal, but the shape of the through-holes 15g is not limited to hexagonal. For example, the through-holes 15g may be polygonal, such as rhombic, rectangular, triangular, or pentagonal, or may be circular or elliptical. However, in order to efficiently mix two types of fluids, it is preferable that the through-holes 15g be polygonal.

[0069] In the present embodiment, the mixing section 15 has two types of plate-like members 15b and 15c, but the mixing section 15 may have three or more types of plate-like members. In addition, in the mixing section 15, it is sufficient that different types of plate-like members are stacked adjacent to each other.

[0070] Furthermore, in the present embodiment, plate-shaped members 15b and 15c are provided so as to abut against end 15h and not abut against end 15i and side surface 15j, but the provision of plate-shaped members 15b and 15c is not limited to this. For example, plate-shaped members 15b and 15c may abut against side surface 15j and not abut against ends 15h and 15i. Even when plate-shaped members 15b and 15c abut against side surface 15j and not abut against ends 15h and 15i, through-hole 15g of plate-shaped member 15b and through-hole 15g of plate-shaped member 15c partially overlap, and the mixed liquid of the liquid to be treated and the mixed fluid repeatedly flows in and out of through-hole 15g, thereby efficiently mixing the liquid to be treated and the mixed fluid.

[0071] Furthermore, in this embodiment, the liquid to be treated is water and the mixed fluid is air, but as in the first embodiment, the liquid to be treated is not limited to water, and the mixed fluid is not limited to air.

[0072] <Modification of the Second Embodiment> Although liquid treatment device 2 has mixer 15 in which plate-like members 15b and 15c are alternately stacked, the shape of the mixer is not limited to this. Fig. 9 is a schematic diagram showing an example of a liquid treatment device 2A having mixer 15A according to a modification. Liquid treatment device 2A differs from liquid treatment device 2 only in mixer 15A.

[0073] 10 is a diagram showing an outline of the mixing section 15A. The mixing section 15A mainly includes two plate-like members 15b and 15c stacked one on top of the other, and two plate-like members 15c stacked on top of the two plate-like members 15b.

[0074] Even in the mixing section 15A, the through hole 15g of the plate-shaped member 15b and the through hole 15g of the plate-shaped member 15c partially overlap, so the flow of the fluid (the mixed liquid of the liquid to be treated and the mixed fluid) passing through the through hole 15g becomes unstable, and the liquid to be treated and the mixed fluid are mixed.

[0075] 11 is a graph comparing the amount of mixed fluid (air) mixed into the liquid to be treated (water) between the mixing section 15 and the mixing section 15A. As can be seen, the mixing section 15 and the mixing section 15A have similar functions. Note that the discharge pressure of the pump 13 in FIG. 11 is the same as the pressure in the dissolution tank 16, 0.5 MPa.

[0076] As with the mixing section 15, the number of plate-like members 15b and 15c in the mixing section 15A is not limited to two. Furthermore, the mixing section 15A may have three or more types of plate-like members. In addition, the mixing section 15A may be configured such that plate-like members of the same type are stacked one on top of the other.

[0077] Third Embodiment In the first embodiment of the present invention, a fluid is mixed into the liquid to be treated using the fluid suction section 12, but the method of mixing a fluid into the liquid to be treated is not limited to this. A liquid treatment device 3 of the present invention will be described below. Note that the same parts as those in the first and second embodiments are designated by the same reference numerals, and descriptions thereof will be omitted.

[0078] 12 is a schematic diagram showing an example of a liquid treatment device 3 according to a third embodiment of the present invention. Liquid treatment device 3 mainly includes tank 11, pump 13, mixer 15, dissolving tank 16, flow control valve 14, flow path 20, and fluid inlet 30.

[0079] The fluid inlet section 30 is provided on the downstream side (return path 22) of the pump 13 of the flow path 20. The fluid inlet section 30 mainly includes a gas tank 31 and a connection section 32.

[0080] The gas tank 31 contains a high-pressure gas. High-pressure gas includes compressed gas and liquefied gas. Compressed gas is defined as a compressed gas having a pressure of 1 MPa or more at normal operating temperatures, and is defined as a compressed gas whose actual pressure is 1 MPa or more, or a compressed gas whose pressure is 1 MPa or more at 35°C. Examples of compressed gas include hydrogen, oxygen, and nitrogen. Liquefied gas is defined as a liquefied gas having a pressure of 0.2 MPa or more at normal operating temperatures, and is defined as a liquefied gas whose actual pressure is 0.2 MPa or more, or a liquefied gas whose temperature at which the pressure reaches 0.2 MPa is 35°C or less. Examples of liquefied gas include carbon dioxide, ammonia, and nitrogen. In this embodiment, carbon dioxide and nitrogen are used as the fluid (mixed fluid) to be mixed with the liquid to be treated.

[0081] The connection part 32 is a member that connects the gas tank 31 and the flow path 20 (return path 22), and includes a pipe, a hose, a joint, etc. The upstream side of the connection part 32 of the return path 22 is an upstream part 22 e, and the downstream side is a midstream part 22 f.

[0082] Next, the operation of the liquid treatment device 3 will be described. When the pump 13 is driven, the liquid to be treated (here, water) flows from the tank 11 into the flow path 20. The liquid to be treated that has flowed into the upstream section 22a is mixed with the mixed fluid sealed in the gas tank 31 via the connection section 32 to form a mixed liquid, which then flows into the midstream section 22f. The mixed liquid then flows into the mixing section 15 and passes through the through-hole 15g, causing the flow to become unstable. As a result, the high-pressure gas turns into fine bubbles, and the fine bubbles are mixed with the water.

[0083] In liquid treatment device 3, flow path 20 constitutes a fluid circulation circuit, and after being treated in mixing section 15 and being dissolved under pressure in dissolution tank 16, the liquid to be treated returns to tank 11, flows again through flow path 20, and is treated in mixing section 15. In the case of a fluid circulation circuit, the same liquid to be treated can be treated multiple times in mixing section 15, and the mixed fluid can be efficiently mixed into the liquid to be treated.

[0084] FIG. 13 is a graph comparing the amount of dissolved mixed fluid (here, carbon dioxide) into the liquid to be treated (water) with and without the mixing unit 15. In FIG. 13, square plots indicate the carbon dioxide (carbonate) concentration when the pump 13, dissolving tank 16, and flow rate control valve 14 are provided (when the mixing unit 15 is not provided), and circle plots indicate the carbon dioxide concentration when the pump 13, mixing unit 15, dissolving tank 16, and flow rate control valve 14 are provided. FIG. 13 reveals that the carbon dioxide concentration is higher when the mixing unit 15 is provided than when the mixing unit 15 is not provided, i.e., more carbon dioxide is dissolved in the water. Note that the discharge pressure of the pump 13 in FIG. 13 is the same as the pressure in the dissolving tank 16 (0.4 MPa), the pressure of carbon dioxide in the gas tank 31 is 0.5 MPa, and the injection rate of carbon dioxide is 3 NL / min.

[0085] FIG. 14 is a graph comparing the amount of mixed fluid (here, nitrogen) mixed into the liquid to be treated (water) with and without the mixing unit 15. Note that FIG. 14(B) is an enlarged portion of FIG. 14(A). When nitrogen is mixed into the liquid to be treated, oxygen is replaced with nitrogen (nitrogen substitution), reducing the amount of dissolved oxygen in the liquid to be treated. Therefore, the amount of nitrogen mixed can be indirectly measured by measuring the amount of dissolved oxygen. From FIG. 14, it can be seen that when the mixing unit 15 is present, the amount of dissolved oxygen decreases more quickly than when the mixing unit 15 is not present, i.e., more nitrogen is mixed into the water. Note that the discharge pressure of the pump 13 in FIG. 14 is the same as the pressure in the dissolution tank 16 (0.4 MPa), the nitrogen pressure in the gas tank 31 is 0.5 MPa, and the nitrogen injection rate is 3 NL / min.

[0086] According to this embodiment, two types of fluids can be efficiently mixed by providing the mixing section 15. In particular, since pressurized dissolution or nitrogen substitution is performed in the dissolution tank 16, the mixed fluid can be efficiently dissolved in or substituted into the liquid to be treated.

[0087] Furthermore, according to this embodiment, the flow path 20 is a fluid circulation circuit through which the treated liquid flowing out of the tank 11 flows and also returns the treated liquid to the tank 11, and the same treated liquid can be treated multiple times in the mixing section 15, and the mixed fluid can be efficiently mixed into the treated liquid.

[0088] In this embodiment, the liquid to be treated is water and the mixed fluid is air, but as in the first and second embodiments, the liquid to be treated is not limited to water, and the mixed fluid is not limited to air.

[0089] The above describes an embodiment of the present invention in detail with reference to the drawings, but the specific configuration is not limited to this embodiment, and design changes and the like are also included within the scope that does not deviate from the gist of the present invention.

[0090] Furthermore, "substantially" is a concept that includes not only cases where something is strictly identical, but also errors or deformations that do not cause loss of identity. For example, "substantially orthogonal" is not limited to cases where something is strictly orthogonal, but also includes cases where something can be regarded as being the same as orthogonal. Furthermore, for example, when simply expressing something as orthogonal, parallel, coincident, etc., it includes not only cases where something is strictly orthogonal, parallel, coincident, etc., but also cases where something is approximately parallel, approximately orthogonal, approximately coincident, etc.

[0091] Furthermore, "vicinity" means including a certain range (which can be arbitrarily determined) near a reference position. For example, "near an edge" is a concept indicating a certain range near the edge, which may or may not include the edge.

[0092] DESCRIPTION OF SYMBOLS 1, 2, 2A, 3: Liquid treatment device 11: Tank 12: Fluid intake section 13: Pump 14: Flow rate control valve 15, 15A: Mixing section 15a: Casing 15b, 15c, 15d: Plate-shaped member 15e: Inlet 15f: Outlet 15g: Through hole 16: Dissolving tank 20: Flow path 21: Outlet path 22: Reflux path 21a, 22a, 22c, 22e: Upstream section 21b, 22b: Downstream section 22d, 22f: Midstream section 30: Fluid inlet section 31: Gas tank 32: Connection section 100: Measuring device 102, 106: Flow path 103: Air reservoir 104: Water reservoir 105: Pressure release valve 111: Outlet 121: First housing 121a: Supply port 121b: Nozzle 122: Second housing 122a: Intake port 122b: Intake chamber 123: Third housing 123a: Outlet port 123b: Contraction section 123c: Diffuser

Claims

a pump provided in the flow path and causing the liquid to be treated to flow from the tank into the flow path; and a fluid suction unit provided in the flow path upstream of the pump and mixing the liquid to be treated with a mixed fluid which is a fluid different from the liquid to be treated, wherein the fluid suction unit has a nozzle, a diffuser and a suction chamber, a supply port communicating with the nozzle and a discharge port communicating with the diffuser are provided in the flow path, the liquid to be treated passes through the nozzle, the suction chamber and the diffuser so that the mixed fluid is sucked into the suction chamber from the suction port which is an inlet to the suction chamber, and the inner diameter of the nozzle is set so that the flow velocity of the liquid to be treated is 5 m / sec or more and 6 m / sec or less.

2. A liquid treatment device as described in claim 1, further comprising a dissolving tank provided downstream of the pump in the flow path, for dissolving the mixed fluid of the liquid to be treated and the mixed fluid under a pressurized environment.

3. A liquid treatment device as described in claim 2, further comprising a mixing section disposed on the flow path downstream of the pump and upstream of the dissolving tank for mixing the mixed fluid with the liquid to be treated, the mixing section comprising a casing having a cylindrical side disposed in the flow path, and a plurality of plate-like members disposed inside the casing, the plate-like members each having a plurality of first through holes through which the liquid to be treated passes, and the plurality of plate-like members being stacked such that the first through hole of a first plate-like member among the plurality of plate-like members partially overlaps with the first through hole of a second plate-like member adjacent to the first plate-like member.

4. A liquid treatment device comprising: a tank for storing a liquid to be treated; a flow path through which the liquid to be treated flowing out of the tank flows and through which the liquid to be treated returns to the tank; a pump provided in the flow path and for discharging the liquid to be treated from the tank into the flow path; a fluid inlet section provided in the flow path downstream of the pump, the fluid inlet section having a gas tank containing a high-pressure gas which is a mixed fluid, and a connection section connecting the gas tank and the flow path; and a mixing section provided in the flow path downstream of the fluid inlet section and mixing the mixed fluid with the liquid to be treated, wherein the mixing section has a casing having a cylindrical side provided in the flow path and a plurality of plate-like members provided inside the casing, the plate-like members being provided with a plurality of first through holes through which the liquid to be treated passes, and the plurality of plate-like members being stacked such that the first through hole of a first plate-like member among the plurality of plate-like members partially overlaps with the first through hole of a second plate-like member adjacent to the first plate-like member.

5. A liquid treatment device as described in claim 4, further comprising a dissolving tank provided downstream of the mixing section of the flow path, for dissolving the fluid obtained after mixing of the liquid to be treated with the mixed fluid under a pressurized environment.

6. A liquid treatment device as described in any one of claims 3 to 5, characterized in that the casing has a first end provided with a third inlet portion which is an inlet for the liquid to be treated, and a second end provided with a second outlet portion which is an outlet for the liquid to be treated, at both ends of the side surface, the plate-shaped member abuts the first end but does not abut the second end and the side surface, and the end of the stacked plurality of plate-shaped members that does not abut the first end is covered by a third plate-shaped member.

7. The liquid treatment device according to any one of claims 1 to 6, characterized in that the liquid to be treated is water, and the mixed fluid is at least one of air, carbon dioxide, and nitrogen.

8. The liquid treatment device according to any one of claims 1 to 6, characterized in that the pump is a positive displacement pump, and the liquid to be treated is a non-Newtonian fluid.

9. The liquid treatment device according to any one of claims 1 to 6, characterized in that the pump is a centrifugal pump, and the liquid to be treated is a Newtonian fluid.

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