Ultraviolet light treatment device

Abstract

A UV irradiation container (11) is configured such that a gas phase space (GPS) and a liquid phase space (LPS) are formed therein, an ultraviolet light source (12) is installed inside the gas phase space (GPS), and ultraviolet light is emitted from the gas phase space to the liquid phase space (LPS). In addition, the following are provided: a gas inlet (11g) through which an oxygen-containing gas is taken into the gas phase space (GPS); and a gas outlet (11h) which discharges, to the outside of the container, an ozone-containing gas, said ozone being generated in the gas phase space by ultraviolet light irradiation. A liquid introduction structure (13) is provided and is configured so as to introduce a liquid to be treated into the UV irradiation container (11), forming the liquid phase space (LPS). The liquid to be treated by ultraviolet light is treated by emitting, from the gas phase space to the liquid to be treated inside the liquid phase space, ultraviolet light from the ultraviolet light source (12).

Description

UV treatment equipment

[0001] The present invention relates to an ultraviolet treatment device that combines the function of generating ozone using ultraviolet rays and the function of treating a liquid (such as deodorizing, decolorizing, sterilizing, decomposing organic matter, and oxidizing inorganic or organic matter in the liquid to be treated).

[0002] Known ozone generators include discharge and ultraviolet (UV) lamp types. Discharge types have the advantage of low gas flow rates and high ozone concentrations, while UV lamp types have the advantage of high gas flow rates and low ozone concentrations. Furthermore, discharge types preferably use oxygen as a raw material; using air as a raw material generates harmful nitrogen oxides (NOx), and the amount of ozone generated (g / h: grams of ozone gas generated per hour) decreases with increasing humidity. UV lamp types have the advantage of not generating NOx even when using air as a raw material, and the amount of ozone generated is not affected by humidity. Patent Document 1 shows an example of such a UV lamp-based ozone generator.

[0003] Ozone generated by an ozone generator is used in a wide variety of applications, such as liquid treatment (deodorization, decolorization, sterilization, decomposition of organic matter, oxidation of inorganic or organic matter, etc. of the liquid to be treated), environmental purification (purification and sterilization of indoor air, etc.), etc. For example, Patent Document 2 discloses an apparatus for treating liquid using ozone gas generated by an ozone generator.

[0004] Meanwhile, ultraviolet irradiation devices are also known that irradiate a liquid to be treated with ultraviolet light emitted from a UV lamp to sterilize the liquid, decompose organic matter, and perform other processes on the liquid. Known ultraviolet irradiation devices include an external irradiation type in which ultraviolet light emitted from a UV lamp is irradiated from outside the liquid to be treated, and an internal irradiation type in which a UV lamp liquid-tightly housed in a protective tube is immersed in the liquid to be treated and ultraviolet light is irradiated from inside the liquid to be treated. For example, Patent Document 3 discloses both the external irradiation type and the internal irradiation type. With the internal irradiation type, since the lamp protective tube comes into contact with the liquid to be treated, there is a problem in that hardness, iron, aluminum, and the like in the liquid to be treated adhere to the outer periphery of the lamp protective tube, blocking the ultraviolet light. Therefore, maintenance work such as periodic cleaning of the lamp protective tube is essential.

[0005] The following Patent Documents 4 and 5 disclose an internal irradiation type ultraviolet irradiation device that not only treats a liquid to be treated by ultraviolet irradiation, but also recovers ozone generated within a lamp protective tube and uses this for ozone reactive treatment of the liquid to be treated. Even in this case, there are the same problems with the internal irradiation type as described above (such as the need for protective tube maintenance). Furthermore, since the ozone generation space is limited to a narrow gap within the protective tube, this device cannot be used as a full-scale ozone generator.

[0006] Typically, in internal irradiation-type liquid treatment devices using ultraviolet lamps, the ultraviolet lamps are housed in an ultraviolet-transparent protective tube, the outer periphery of which comes into contact with the liquid being treated. When the liquid being treated is ion-exchanged water, RO permeate water, or the like (i.e., pure water or ultrapure water), the liquid-contacting surface of the protective tube is not contaminated by impurities or hardness in the liquid being treated. However, when the liquid being treated is raw tap water, wastewater, pool water, hot spring water, sewage, sewage treatment water, seawater, or the like, contamination on the liquid-contacting surface of the protective tube can cause the ultraviolet light from the ultraviolet lamp to be absorbed by the contamination before it is irradiated onto the liquid, reducing the effectiveness of the ultraviolet irradiation on the liquid being treated. To address this issue, maintenance such as physically scraping off the contamination from the protective tube with a brush or chemically cleaning the protective tube by dissolving the contamination with chemicals is essential. This requires the installation of an expensive cleaning mechanism, which increases costs.

[0007] Japanese Utility Model Application Publication No. 04-56724 Japanese Patent Publication No. 2003-190976 Japanese Patent Publication No. 11-156352 Japanese Patent Publication No. 2014-195770 Japanese Patent Publication No. 2014-195788

[0008] The present invention provides an ultraviolet treatment apparatus that combines the functions of generating ozone using ultraviolet light and treating liquid.

[0009] The ultraviolet treatment device of the present invention comprises an ultraviolet light source, a UV irradiation container configured to form a gas phase space and a liquid phase space therein, the ultraviolet light source being installed in the gas phase space, and configured to irradiate ultraviolet light from the gas phase space to the liquid phase space, the UV irradiation container having a gas inlet for introducing oxygen-containing gas into the gas phase space and a gas outlet for discharging ozone-containing gas generated by ultraviolet irradiation in the gas phase space to the outside of the container, and a liquid introduction structure that forms the liquid phase space by introducing a liquid to be treated into the UV irradiation container and irradiates the liquid to be treated in the liquid phase space with ultraviolet light from the ultraviolet light source installed in the gas phase space.

[0010] According to the present invention, full-scale ozone generation is performed in the gas phase space within the UV irradiation container by UV irradiation, and full-scale UV treatment of the liquid to be treated is performed in the liquid phase space within the UV irradiation container by the same UV irradiation. Therefore, an efficient UV treatment device can be provided that combines both UV-based ozone generation and liquid treatment functions (such as deodorizing, decolorizing, sterilizing, decomposing organic matter, and oxidizing inorganic or organic matter in the liquid to be treated). Furthermore, UV irradiation of the liquid to be treated in the liquid phase space is performed by a UV light source installed in the gas phase space, so the UV light source is not in contact with the liquid to be treated in the liquid phase space (external irradiation method). Therefore, the aforementioned problems associated with internal irradiation methods can be avoided. Furthermore, because the gas phase space for ozone generation is formed within the UV irradiation container, the container can be made airtight, easily and reliably preventing ozone loss into the external surrounding environment.

[0011] 1 is a side perspective view schematically showing the configuration of an ultraviolet treatment apparatus according to an embodiment of the present invention; FIG. 2 is a side perspective view schematically showing the configuration of an ultraviolet treatment apparatus according to another embodiment of the present invention; FIG. 3 is a side perspective view schematically showing the configuration of an ultraviolet treatment apparatus according to yet another embodiment of the present invention; FIG. 4 is a side perspective view schematically showing the configuration of an ultraviolet treatment apparatus according to an embodiment of the present invention which is a modification of FIG.

[0012] In FIG. 1 , the ultraviolet treatment device 10 includes a UV irradiation container 11 that is airtight and liquid-tight throughout, except for a designated inlet and outlet. The UV irradiation container 11 is configured to define a gas-phase space (GPS) and a liquid-phase space (LPS) therein, with an ultraviolet light source 12 installed within the gas-phase space (GPS). The ultraviolet light source 12 includes an ultraviolet lamp that generates ultraviolet light having a wavelength of 190 nm or less, which is suitable for ozone generation, and a wavelength (e.g., 254 nm), which is suitable for liquid treatment (deodorization, decolorization, sterilization, organic decomposition, and oxidation of inorganic or organic matter in the liquid being treated). Known examples of such ultraviolet lamps include low-pressure mercury lamps and excimer lamps. Because the ultraviolet light source 12 is not immersed in the liquid being treated in the liquid-phase space (LPS), as described below, there is no need to house the ultraviolet lamp in a special protective tube that is UV-transparent. This has the advantage of eliminating the need for a mechanism for cleaning the protective tube. However, the ultraviolet lamp may be housed in such a protective tube, and even in this case, since the ultraviolet light source 12 is not immersed in the liquid to be treated, there is the advantage that a mechanism for cleaning the protective tube is not required. Of course, the number of ultraviolet light sources 12 installed in the UV irradiation container 11 is not limited to one and can be any number. Furthermore, the ultraviolet light source 12 installed in the UV irradiation container 11 is designed to be detachable from the container 11 for maintenance such as lamp replacement, but detailed illustration thereof is omitted.

[0013] As an example, the UV irradiation container 11 is made of a sturdy cylindrical metal housing, with end plate companion flanges 11a, 11b formed on both ends of the metal housing. The end plate companion flanges 11a, 11b are tightly engaged with outer end plate flanges 11e, 11f via O-rings 11c, 11d, respectively. These flanges are appropriately provided with a gas inlet 11g for introducing oxygen-containing gas (e.g., outside air) into the gas phase space GPS, and a gas outlet 11h for discharging ozone-containing gas generated by ultraviolet irradiation in the gas phase space GPS to the outside of the container. Specifically, ozone is generated by irradiating ultraviolet light from the ultraviolet light source 12 onto the oxygen-containing gas introduced into the gas phase space GPS through the gas inlet 11g, and the generated ozone-containing gas is discharged through the gas outlet 11h. Of course, an external pipe (not shown) is attached to the gas outlet 11h, and the system is configured so that the generated ozone-containing gas is sent to a device (not shown) for utilizing the ozone-containing gas. An appropriate pump or the like may be provided to draw the oxygen-containing gas into the interior through the gas inlet 11g or to discharge the ozone-containing gas from the gas outlet 11h, but this is not shown. Of course, the shape of the UV irradiation container 11 is not limited to a cylindrical shape, and may be any shape, such as a polygonal cross-section such as a triangular or rectangular cross-section, a semi-cylindrical shape, or a semi-cylindrical shape.

[0014] A liquid introduction structure 13 is provided in association with the UV irradiation container 11. This liquid introduction structure 13 is configured to form the liquid phase space LPS by introducing the liquid to be treated into the UV irradiation container 11. For example, the liquid introduction structure 13 has a liquid inlet 13a through which the liquid to be treated is introduced into the UV irradiation container 11. The liquid to be treated is introduced into the UV irradiation container 11 through the liquid inlet 13a, thereby forming the liquid phase space LPS within the UV irradiation container 11. This structure allows ultraviolet light from an ultraviolet light source 12 installed in the gas phase space GPS to irradiate the liquid to be treated in the liquid phase space LPS, thereby subjecting the liquid to ultraviolet treatment (deodorization, decolorization, sterilization, organic matter decomposition, oxidation of inorganic or organic matter, etc.). In FIG. 1 , the liquid introduction structure 13 further has a liquid outlet 13b through which the liquid to be treated that has been irradiated with ultraviolet light in the liquid phase space LPS is discharged out of the container 11. Of course, an external pipe or flow path (not shown) is appropriately connected to the liquid outlet 13b, and the system is configured so that the liquid to be treated (treated liquid) that has been treated with ultraviolet light is sent to an apparatus (not shown) for utilizing the treated liquid.

[0015] In the example of Fig. 1, the liquid inlet 13a and liquid outlet 13b are appropriately positioned in the flange portions at both ends of the cylindrical UV irradiation container 11. In the example of Fig. 1, there is no physical barrier at the boundary between the gas phase space GPS and the liquid phase space LPS, and the presence of the liquid to be treated in the UV irradiation container 11 forms the liquid phase space LPS, with the space above it being the gas phase space GPS. In other words, the upper part of the internal space of the UV irradiation container 11 is the gas phase space GPS, and the lower part is the liquid phase space LPS. This has the advantage that if condensation occurs on the ultraviolet light source 12 located in the upper gas phase space GPS, the condensed water will drip into the lower liquid phase space LPS and be naturally collected, eliminating the need for special condensation countermeasures.

[0016] It is desirable to take appropriate measures to ensure a required spatial region for the gas-phase space GPS in which the ultraviolet light source 12 is disposed. For example, a liquid overflow outlet (not shown) may be provided at an appropriate location on the wall of the UV irradiation container 11 to define the upper limit height of the liquid to be treated that forms the liquid-phase space LPS. Alternatively, the upper limit height of the liquid to be treated that forms the liquid-phase space LPS may be limited (at least to prevent the liquid from coming into contact with the ultraviolet light source 12) by appropriately setting or managing the inflow and outflow (e.g., flow rate) of the liquid to be treated into the UV irradiation container 11 via the liquid inlet 13a and the liquid outlet 13b, or by appropriately setting or managing the inflow and outflow (or internal gas pressure) of the gas into the UV irradiation container 11 via the gas inlet 11g and the gas outlet 11h.

[0017] Next, another embodiment of the present invention will be described with reference to Fig. 2. The UV irradiation container 11 of the ultraviolet treatment device 10 shown in Fig. 2 is not a sealed container as shown in Fig. 1, but is an open-bottom container having a relatively wide opening 12i formed at its bottom. This bottom opening 12i corresponds to the aforementioned liquid introduction structure 13. That is, the UV irradiation container 11 shown in Fig. 2 is provided with the aforementioned gas inlet 11g and gas outlet 11h, but is not provided with the liquid inlet 13a and liquid outlet 13b as shown in Fig. 1. Instead, it is provided with the bottom opening 12i, which functions as the liquid introduction structure 13.

[0018] 2, the liquid to be treated is contained (or flowed) in an appropriate container (or flow path) 14, and the liquid to be treated is contained (or flowed) in the container (or flow path) 14 so that an appropriate space is left above the liquid surface of the liquid to be treated. The UV irradiation container 11 is installed relative to the container (or flow path) 14 so that the lower part of the UV irradiation container 11 is immersed in the liquid to be treated in the container (or flow path) 14. This allows the liquid to be treated in the container (or flow path) 14 to flow in and out of the lower region of the UV irradiation container 11 through the lower opening 12i, thereby forming the liquid phase space LPS within the UV irradiation container 11. The internal space of the UV irradiation container 11 in the part of the container (or flow path) 14 that is not immersed in the liquid to be treated becomes a gas phase space GPS, and an ultraviolet light source 12 is installed in the gas phase space GPS, as in FIG. 1. In other words, the liquid level of the liquid to be treated in the container (or flow path) 14 should be appropriately limited so as to form the necessary gas phase space GPS in the UV irradiation container 11. As an example, the UV irradiation container 11 shown in Fig. 2 is made of a roughly rectangular parallelepiped housing, and at least a portion of the bottom thereof is open to form an opening 12i.

[0019] In the embodiment of Fig. 2, as in the embodiment of Fig. 1, the upper part of the internal space of the UV irradiation container 11 is a gas phase space GPS, and the lower part is a liquid phase space LPS. An ultraviolet light source 12 is installed in the gas phase space GPS. Ozone is generated by irradiating ultraviolet light from the ultraviolet light source 12 onto an oxygen-containing gas introduced into the gas phase space GPS through a gas inlet 11g, and the generated ozone-containing gas is discharged through a gas outlet 11h. Of course, as described above, an external pipe (not shown) is attached to the gas outlet 11h, and the system is configured so that the generated ozone-containing gas is sent to a device (not shown) for utilizing the generated ozone-containing gas. Although the UV irradiation container 11 shown in Fig. 2 is not a sealed container, the gas phase space GPS formed inside is sealed by the liquid phase space LPS (i.e., the liquid to be treated) below it, so that the generated ozone does not leak to the outside.

[0020] 2, ultraviolet light from an ultraviolet light source 12 installed in the gas-phase space GPS is irradiated onto the liquid to be treated that has entered the lower region of the UV irradiation container 11, i.e., the liquid-phase space LPS, from the container (or flow path) 14 through the opening 12i (liquid introduction structure 13). As described above with reference to FIG. 1, the liquid to be treated is subjected to ultraviolet treatment (deodorization, decolorization, sterilization, decomposition of organic matter, oxidation of inorganic or organic matter, etc.). The container (or flow path) 14 is provided with a structure (not shown) for discharging the treated liquid (treated liquid) that has been subjected to ultraviolet treatment to the outside, and the system is configured so that the treated liquid is sent to a utilization device (not shown) for utilizing the treated liquid. If the container (or flow path) 14 is not a flow path but a liquid storage container such as a tank, it is preferable to create an appropriate flow of the treated liquid in the container 14 so that the treated liquid entering and leaving the liquid-phase space LPS can be appropriately replaced. The top of the container (or flow path) 14 may be open or may be closed with a lid or the like, as long as there is an appropriate space above the liquid level of the liquid to be treated contained (or flowing) in the container (or flow path) 14. As an example, the container (or flow path) 14 is a tank that stores the liquid to be treated, and has a liquid inlet (not shown) and outlet (not shown), and the system can be configured so that the treated liquid discharged from the outlet is used in the utilization device, and then the used liquid is returned to the inlet of the tank (container 14) as the liquid to be treated.

[0021] Another embodiment will be described with reference to Figure 3. The UV irradiation vessel 11 of the ultraviolet treatment device 10 shown in Figure 3 includes a wetted wall tower 110. The wetted wall tower 110 has, for example, a vertically placed cylindrical shape, and a liquid introduction structure 13 is installed at its upper part. The liquid introduction structure 13 includes a liquid inlet 13a and is configured to introduce the liquid to be treated into the upper periphery of the wetted wall tower 110. The liquid introduction structure 13 is configured, for example, in a ring shape so that the liquid to be treated introduced from the liquid inlet 13a flows around the upper periphery of the wetted wall tower 110 in a ring shape and flows down evenly from the upper periphery along the cylindrical inner wall of the wetted wall tower 110. An appropriate opening is provided at the bottom of the wetted wall tower 110 as a gas inlet 11g, and a gas outlet 11h is provided at the top of the wetted wall tower 110. This gas outlet 11h passes through the central space of the ring-shaped liquid introducing structure 13 and communicates with the upper part of the wetted wall tower 110, and further communicates with the internal space thereof. In addition, an appropriate opening is provided at the bottom of the wetted wall tower 110 so that the liquid that flows down along the inner wall drips downward. A receiver 13c is arranged below the wetted wall tower 110 with an appropriate space therebetween, and a liquid outlet 13a is provided in this receiver 13c.

[0022] With this configuration, the region where the liquid to be treated exists along the cylindrical inner wall of the wetted wall tower 110 becomes the liquid phase space LPS, and the remaining space closer to the interior of the wetted wall tower 110 becomes the gas phase space GPS. As described above, the ultraviolet light source 12 is installed in the gas phase space GPS within the wetted wall tower 110. It is preferable to provide an appropriate pump or the like in the external piping (not shown) connected to the gas outlet 11h to gently suck the gas inside the wetted wall tower 110 upward, thereby creating a relatively weak gas flow from bottom to top within the wetted wall tower 110. It is desirable that the motor suction force that causes this relatively weak upward gas flow be sufficient so as not to interfere with the downward flow of the liquid along the inner wall of the wetted wall tower 110. This allows the generated ozone to be effectively discharged from the gas outlet 11h.

[0023] In Figure 3, air (oxygen-containing gas) is introduced into the gas phase space GPS through a gas inlet 11g at the bottom of the wetted wall tower 110. UV light is irradiated from the UV light source 12, generating ozone. The generated ozone-containing gas is then discharged through a gas outlet 11h at the top. As described above, an external pipe (not shown) is attached to the gas outlet 11h, and the system is configured so that the generated ozone-containing gas is sent to a device (not shown) for utilizing the ozone-containing gas. Furthermore, UV light from the UV light source 12 installed in the gas phase space GPS is irradiated onto the liquid to be treated (i.e., the liquid phase space LPS) flowing down the inner wall of the wetted wall tower 110, and UV treatment of the liquid to be treated (deodorization, decolorization, sterilization, organic matter decomposition, oxidation of inorganic or organic matter, etc.) is performed on the liquid to be treated. As described above, an external pipe or flow path (not shown) is appropriately connected to the liquid outlet 13b, and the system is configured so that the UV-treated liquid (treated liquid) is sent to a device (not shown) for utilizing the treated liquid. The wetted-wall tower 110 is not limited to a cylindrical shape and may have any other appropriate cross-sectional shape. The gentle gas suction upward (gas outlet 11h) as described above is also effective in preventing ozone leakage from the lower opening (gas inlet 11g) when the lower gas inlet 11g is opened to the outside environment.

[0024] FIG. 4 shows a modification of FIG. 3 . In FIG. 4 , a gas inlet 11g is provided near the bottom of the wall of the wetted wall tower 110, and an appropriate opening is provided in the lower part of the wetted wall tower 110 so that at least the liquid flowing down along the inner wall can be discharged downward. In this modification, the lower part of the wetted wall tower 110 may be appropriately immersed in the liquid in the receiver 13c, as shown in the figure. In FIG. 4 , ultraviolet treatment (ozone generation and liquid treatment) is performed as in FIG. 3 . Furthermore, as a modification of FIG. 4 , the receiver 13 may be omitted, and the lower part (bottom) of the wetted wall tower 110 may be closed so that the liquid flowing down along the inner wall temporarily remains there. In this case, the liquid outlet 13b is provided in the lower part of the wetted wall tower 110. 3 and 4, the ultraviolet light source 12 is not immersed in the liquid to be treated in the liquid-phase space LPS, so there is no need to house the ultraviolet lamp in a special protective tube that is ultraviolet-transparent, and even if it is housed in a protective tube, it does not get dirty, so cleaning of the protective tube is not necessary. Therefore, there is an advantage in that a mechanism for cleaning the protective tube is not required.

[0025] It is preferable to take measures to prevent corrosion by ozone for the UV irradiation container 11 and other parts that come into contact with the generated ozone. For example, it is recommended to use ozone-resistant materials (such as stainless steel such as SUS304 or SUS316, or ceramics) for each component. Other ozone-resistant materials include titanium, aluminum, epoxy resin, fluorocarbon resin, silicone resin, ethylene propylene diene rubber (EPDM), and fluororubber (FKM), so these materials can be used for piping, packing, O-rings, etc. as needed.

Claims

1. An ultraviolet treatment device comprising: an ultraviolet light source; a UV irradiation container configured to form a gas phase space and a liquid phase space therein, the ultraviolet light source being installed in the gas phase space, and configured to irradiate ultraviolet light from the gas phase space to the liquid phase space, the UV irradiation container having a gas inlet for taking in gas containing oxygen into the gas phase space and a gas outlet for discharging gas containing ozone generated by ultraviolet irradiation in the gas phase space to the outside of the container; and a liquid introduction structure that forms the liquid phase space by introducing a liquid to be treated into the UV irradiation container, and irradiates the liquid to be treated in the liquid phase space with ultraviolet light from the ultraviolet light source installed in the gas phase space.

2. The ultraviolet treatment device of claim 1, wherein the liquid introduction structure has a liquid inlet for introducing the liquid to be treated into the liquid phase space of the UV irradiation container, and a liquid outlet for discharging the liquid to be treated that has been irradiated with ultraviolet rays in the liquid phase space out of the container.

3. The ultraviolet treatment device of claim 1, wherein the liquid introduction structure comprises an opening formed in the lower part of the UV irradiation container, the liquid to be treated is contained in a container or flow path with a space above the liquid surface, and the lower part of the UV irradiation container is immersed in the liquid to be treated contained in the container or flow path, thereby causing the liquid to enter and exit the lower region of the UV irradiation container through the opening, thereby forming the liquid phase space.

4. The ultraviolet treatment device according to claim 1, wherein the UV irradiation container includes a wetted-wall tower, the liquid introduction structure is configured to introduce the liquid to be treated into the upper peripheral edge of the wetted-wall tower, and the introduced liquid to be treated flows down along the inner wall of the wetted-wall tower, thereby forming the liquid phase space by the flowing down liquid to be treated.

5. An ultraviolet treatment device according to any one of claims 1 to 4, wherein there is no physical barrier at the boundary between the gas phase space and the liquid phase space, and the upper part of the internal space of the UV irradiation container is the gas phase space and the lower part is the liquid phase space.

6. An ultraviolet treatment device according to any one of claims 1 to 4, wherein the ultraviolet light source includes an ultraviolet lamp that generates ultraviolet light having a wavelength suitable for generating ozone and a wavelength suitable for liquid treatment such as sterilization or decomposition of organic matter.

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