Oil-water separation device

Abstract

To provide a membrane separation apparatus which suppresses an increase in size of an apparatus shape by serially connecting a plurality of membrane cartridges, and suppresses leakage of a liquid from a connection part of the plurality of serially-connected membrane cartridges.SOLUTION: An oil-water separator 1 includes: a tightly-sealed container 2, a plurality of membrane cartridges 4 which are mounted on the tightly-sealed container 2 in a state of forming a cylindrical shape and being serially connected; a first end plate 5 and a second end plate 6 which are arranged on both ends of the plurality of membrane cartridges 4; at least one ring-shaped gasket 7 which is mounted on one of the two adjacent membrane cartridges 4 of the plurality of membrane cartridges 4, and seals a connection part of the adjacent two membrane cartridges 4; centering means 8 which aligns the plurality of membrane cartridges 4 so that center axes of liquid flow passages 40 thereof are positioned on the same line; and fixing means 9 which fixes the second end plate 6 in a pressed state to a first end plate 5 side and sandwiches and holds the plurality of membrane cartridges 4 between the first end plate 4 and the second end plate 5.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a membrane separation device for separating a predetermined substance mixed in a liquid such as sewage or wastewater from the liquid, and relates to a membrane separation device characterized by a structure in which a plurality of membrane cartridges are connected in series. [Background technology]

[0002] One such type of membrane separation device is an oil-water separator, which separates oil from an oil-water mixture, such as grease, mixed with water, such as building water on a ship. The oil-water separator is equipped with a membrane cartridge called a coalescer. As the oil-water mixture passes through the coalescer, oil droplets that become cloudy in the mixture are captured by the coalescer, and the captured oil droplets combine to form coarse particles. As a result, the coarse oil droplets increase their buoyancy after detaching from the coalescer and rise up within the oil-water separator, separating the oil from the oil-water mixture.

[0003] In order to improve the oil separation performance of an oil-water separation device, it is necessary to increase the membrane area per unit area of ​​installation of the device. Here, the size (length and outer diameter) of membrane cartridges is generally limited due to manufacturing, and the length, etc. cannot be easily changed. Therefore, in order to increase the above-mentioned membrane area, it is necessary to increase the number of membrane cartridges housed in the device. When housing multiple membrane cartridges in a device, it is common to arrange the multiple membrane cartridges in parallel, as in Patent Document 1, for example. However, this increases the size of the device, increasing the floor area occupied by the device. Furthermore, when removing and installing multiple membrane cartridges during maintenance, it is necessary to remove and install each membrane cartridge individually, which poses problems such as the labor and time required for the work. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 52-86875 Summary of the Invention [Problem to be solved by the invention]

[0005] When multiple membrane cartridges are housed in a device, connecting them in series can help prevent the device from becoming too large. However, there is no established method for connecting multiple membrane cartridges connected in series, and there is a concern that liquid may leak from the connections.

[0006] The present invention aims to provide a membrane separation device, such as an oil-water separator, having a structure in which a plurality of membrane cartridges are connected in series, which can solve the above-mentioned problems. [Means for solving the problem]

[0007] The present invention relates to a membrane separation device for separating a predetermined substance mixed in a liquid from the liquid. The membrane separation device of the present invention is characterized by comprising: a sealed container; a plurality of membrane cartridges each having a cylindrical shape and having a liquid flow path therein and attached to the sealed container while being connected in series; first and second end plates disposed at both ends of the plurality of membrane cartridges connected in series; at least one ring-shaped gasket attached to one of two adjacent membrane cartridges of the plurality of membrane cartridges connected in series to seal the connection between the two adjacent membrane cartridges; centering means for aligning the plurality of membrane cartridges connected in series so that the central axes of the liquid flow paths of each membrane cartridge are aligned in the same line; and fixing means for sandwiching and holding the plurality of membrane cartridges connected in series between the first and second end plates by pressing the second end plate against the first end plate.

[0008] In the membrane separation device of the present invention, preferably, the first end plate is provided with at least three rod-shaped members extending parallel to each other toward the second end plate, the at least three rod-shaped members constituting the centering means, the at least three rod-shaped members being arranged at equal intervals circumferentially on the first end plate so as to be close to the periphery of the plurality of membrane cartridges connected in series, and the fixing means can be configured to be composed of the rod-shaped members and fixing devices that fix the second end plate pressed against the first end plate to the rod-shaped members.

[0009] Furthermore, the membrane separation apparatus of the present invention can preferably be configured such that an inner tube is provided on the first end plate, extending toward the second end plate and inserted into the interiors of a plurality of the membrane cartridges connected in series, the inner tube constituting the centering means, the inner tube having an open end on the first end plate side and a closed end on the second end plate side, a plurality of liquid passage holes formed in the peripheral wall, and liquid being introduced into the interior through the openings.

[0010] Furthermore, in the membrane separation apparatus of the present invention, preferably, a rod-shaped member penetrating the second end plate protrudes from the end face of the inner tube on the second end plate side, and the fixing means is composed of the rod-shaped member and a fixing tool that fixes the second end plate pressed against the first end plate side to the rod-shaped member.

[0011] Furthermore, in the membrane separation device of the present invention, preferably, a connector is interposed between two adjacent membrane cartridges of the plurality of membrane cartridges connected in series, at least one of the connectors constitutes the centering means, and the connector can be configured to include a cylindrical portion that is inserted into the interior of the two adjacent membrane cartridges, and a protruding portion that protrudes from the outer peripheral surface of the cylindrical portion and is sandwiched between the two adjacent membrane cartridges.

[0012] Furthermore, in the membrane separation device of the present invention, preferably, the gasket is attached to the end face of one of two adjacent membrane cartridges among a plurality of membrane cartridges connected in series, a cylindrical guide is integrally formed on the inside of the gasket, at least one of the guides constitutes the centering means, and the guide is inserted into the interior of the other of the two adjacent membrane cartridges.

[0013] Furthermore, the membrane separation device of the present invention can preferably be configured such that a connecting pipe protrudes from the end face of one of two adjacent membrane cartridges among the plurality of membrane cartridges connected in series, at least one of the connecting pipes constitutes the centering means, and the connecting pipe is inserted into the other of the two adjacent membrane cartridges.

[0014] Furthermore, the membrane separation device of the present invention can preferably be configured so that the gasket is provided between the outer peripheral surface of the connecting pipe and the inner peripheral surface of the membrane cartridge into which the connecting pipe is inserted.

[0015] The membrane separation device of the present invention can preferably be configured as an oil-water separation device. [Effects of the Invention]

[0016] According to the membrane separation device of the present invention, by connecting multiple membrane cartridges in series, it is possible to prevent the device shape from becoming larger, and it is also possible to prevent liquid leakage from the connection parts of multiple membrane cartridges connected in series. [Brief explanation of the drawings]

[0017] [Figure 1] 1 is a longitudinal cross-sectional view showing the schematic structure of an oil-water separation device, which is one embodiment of a membrane separation device of the present disclosure. [Figure 2]FIG. 4 is an enlarged front view showing the mounting portion of the sealed container. [Figure 3] FIG. 3 is an enlarged cross-sectional view showing the vicinity of a mounting portion of the sealed container. [Figure 4] FIG. 2 is a side view of the filter unit. [Figure 5] FIG. 2 is a perspective view of the filter unit, showing the first end plate, the membrane cartridge, and the second end plate in an exploded state. [Figure 6] 6 is a longitudinal cross-sectional view of the filter unit of FIG. 5, in which a plurality of membrane cartridges connected in series are sandwiched between a first end plate and a second end plate. FIG. [Figure 7] FIG. 6 is a front view of the filter unit of FIG. 5 (a view of the first end plate viewed directly from the outer surface). [Figure 8] FIG. 6 is a rear view of the filter unit of FIG. 5 (a view of the second end plate viewed directly from the outer surface). [Figure 9] 5 is a cross-sectional view taken along the line AA in FIG. 4. [Figure 10] This is an oblique view of a filter unit in an oil-water separation device of another embodiment, showing the first end plate, membrane cartridge, and second end plate in an exploded state. [Figure 11] 11 is a longitudinal cross-sectional view of the filter unit of FIG. 10, in which a plurality of membrane cartridges connected in series are sandwiched between a first end plate and a second end plate. FIG. [Figure 12] This is an oblique view of a filter unit in an oil-water separation device of another embodiment, showing the first end plate, membrane cartridge, and second end plate in an exploded state. [Figure 13] 13 is a longitudinal cross-sectional view of the filter unit of FIG. 12, in which a plurality of membrane cartridges connected in series are sandwiched between a first end plate and a second end plate. FIG. [Figure 14] FIG. 13 is a rear view of the filter unit of FIG. 12 (a view of the second end plate viewed directly from the outer surface). [Figure 15] This is an oblique view of a filter unit in an oil-water separation device of another embodiment, showing the first end plate, membrane cartridge, and second end plate in an exploded state. [Figure 16] 16 is a longitudinal cross-sectional view of the filter unit of FIG. 15, in which a plurality of membrane cartridges connected in series are sandwiched between a first end plate and a second end plate. FIG. [Figure 17] FIG. 16 is a front view of the filter unit of FIG. 15 (a view of the first end plate viewed directly from the outer surface). [Figure 18] FIG. 16 is a rear view of the filter unit of FIG. 15 (a view of the second end plate viewed directly from the outer surface). [Figure 19] This is an oblique view of a filter unit in an oil-water separation device of another embodiment, showing the first end plate, membrane cartridge, and second end plate in an exploded state. [Figure 20] FIG. 20 is a longitudinal cross-sectional view of the filter unit of FIG. 19, in which a plurality of membrane cartridges connected in series are sandwiched between a first end plate and a second end plate. [Figure 21] FIG. 20 is a front view of the filter unit of FIG. 19 (a view of the first end plate viewed directly from the outer surface). [Figure 22] FIG. 20 is a rear view of the filter unit of FIG. 19 (a view of the second end plate viewed directly from the outer surface). DETAILED DESCRIPTION OF THE INVENTION

[0018] Overview of membrane separation equipment The membrane separation device of the present disclosure is a device that separates a predetermined substance mixed in a liquid by passing the liquid containing impurities through a selective membrane (partition wall), such as a filtration membrane. The membrane separation device of the present disclosure is characterized by a structure in which multiple membrane cartridges are connected in series. Hereinafter, an embodiment of the membrane separation device of the present disclosure will be described with reference to the accompanying drawings.

[0019] In the following embodiments, an example in which the membrane separation device is an oil-water separation device is described. Note that the membrane separation device of the present disclosure is not limited to oil-water separation devices, and can be widely applied to devices that use membranes to separate a predetermined substance from a liquid containing impurities.

[0020] Description of the overall configuration of the oil-water separation device (one embodiment of the membrane separation device) FIG. 1 shows a schematic configuration of an oil-water separation device 1 according to one embodiment of the present disclosure. The oil-water separation device 1 separates oil from wastewater, which is a mixture of water, such as building water on a ship, and oil such as grease. The liquid to be treated (liquid to be treated) is not limited to building water generated on ships. The device can also separate oil-water mixtures, such as wastewater from homes, buildings, restaurants, etc., wastewater from various factories, and water from rivers or oceans where oil has been spilled due to an accident, into oil and water. The oil-water separation device 1 includes a sealed container 2 and at least one filter unit 3 for separating oil from the liquid to be treated. The filter unit 3 is removably attached to the sealed container 2.

[0021] Description of airtight container 1 to 3, the sealed container 2 includes a circular cylindrical peripheral wall portion 20, a bottom portion 21 that closes the lower end opening of the peripheral wall portion 20, and an upper lid portion 22 that closes the upper end opening of the peripheral wall portion 20. A circular cylindrical mounting portion 23 is provided on the peripheral wall portion 20 so as to protrude horizontally from the outer periphery. The mounting portion 23 allows the filter unit 3 to be inserted into and removed from the sealed container 2 sideways. The number of mounting portions 23 provided on the peripheral wall portion 20 corresponds to the number of filter units 3; in this embodiment, there is one mounting portion, but there may be multiple mounting portions.

[0022] A flange is provided at the tip of the mounting portion 23, and a plurality of through holes 24 are formed in the flange at equal intervals along the circumferential direction. A pair of guide rails 25 extend horizontally parallel to each other from the mounting portion 23 toward the inside of the sealed container 2, with their ends located near the peripheral wall portion 20 on the opposite side from the mounting portion 23. The pair of guide rails 25 are fixed to a pair of support portions 26 provided at a distance from each other on the bottom of the inner surface of the mounting portion 23. The pair of guide rails 25 support the filter unit 3 from below when the filter unit 3 is inserted or removed sideways into or from the sealed container 2 via the mounting portion 23. Note that at least two guide rails 25 are required, and three or more guide rails 25 may be used.

[0023] The liquid to be treated is supplied from the liquid guide portion 53 of the filter unit 3 into the inside of the filter unit 3, passes through the filter unit 3, and is then supplied into the sealed container 2. A flow path and an on-off valve V1 are connected to the liquid guide portion 53, and the liquid to be treated is supplied from the liquid guide portion 53 into the inside of the filter unit 3 when the on-off valve V1 is opened.

[0024] A cylindrical discharge part 27 is provided on the peripheral wall part 20 above the filter unit 3 for discharging oil that has risen to the surface and separated from the liquid to be treated that has passed through the filter unit 3 from the sealed container 2. A flow path and an on-off valve V2 are connected to the discharge part 27, and the oil is discharged from the discharge part 27 to the outside of the sealed container 2 when the on-off valve V2 is opened.

[0025] A circular cylindrical discharge part 28 is provided on the peripheral wall part 20 at a position immediately above the bottom part 22 for discharging the treated liquid (treated liquid) from which the oil has separated and whose oil concentration has decreased from the sealed container 2. A flow path and an on-off valve V3 are connected to the discharge part 28, and the treated liquid is discharged from the discharge part 28 to the outside of the sealed container 2 when the on-off valve V3 is opened.

[0026] A cylindrical discharge part 29 is provided on the peripheral wall part 20 at a position immediately above the bottom part 22 and at a different circumferential position from the discharge part 28, for discharging drainage such as moisture and sludge that has settled on the bottom part 22 from the sealed container 2. A flow path and an on-off valve V4 are connected to the discharge part 29, and the drainage is discharged from the discharge part 29 to the outside of the sealed container 2 when the on-off valve V4 is opened.

[0027] Filter unit description As shown in Figures 4 and 5, the filter unit 3 comprises a plurality of cylindrical membrane cartridges 4 connected in series, a first end plate 5 and a second end plate 6 arranged at both ends of the plurality of membrane cartridges 4 connected in series, a plurality of ring-shaped gaskets 7 attached to one of two adjacent membrane cartridges 4 of the plurality of membrane cartridges 4 connected in series to seal the connection portion of the two adjacent membrane cartridges 4, a centering means 8 for aligning the plurality of membrane cartridges 4 connected in series, and a fixing means 9 for fixing the plurality of membrane cartridges 4 connected in series between the first end plate 5 and the second end plate 6.

[0028] Membrane Cartridge Description 4 to 6 and 9, the membrane cartridge 4 is cylindrical and has a liquid flow path 40 therein. The liquid to be treated is supplied to the liquid flow path 40 from an opening at one end of the membrane cartridge 4. The liquid to be treated supplied to the liquid flow path 40 of the membrane cartridge 4 passes through a filter member 41 (described later) and is discharged to the outside of the membrane cartridge 4, and can also be discharged to the outside of the membrane cartridge 4 from an opening at the other end of the membrane cartridge 4.

[0029] The membrane cartridge 4 includes a filter member 41 for separating predetermined substances from the liquid to be treated, outer and inner reinforcing members 42, 43 for reinforcing the filter member 41, and a pair of cover members 44 for uniting the filter member 41 and the two reinforcing members 42, 43.

[0030] In this embodiment, the filter element 41 has the function of capturing oil droplets that become cloudy in the liquid being treated as the liquid passes through the filter element 41, and increasing the oil droplet diameter by combining the oil droplets together and coarsening them. The coarse oil droplets have increased buoyancy, so after detaching from the filter element 41 to the outside of the membrane cartridge 4, they float up inside the sealed container 2, accumulating at the top of the sealed container 2 and separating from the liquid being treated. The oil that has accumulated at the top of the sealed container 2 is discharged from the discharge part 27 to the outside of the sealed container 2.

[0031] The filter element 41 can be formed, for example, by a cylindrical body formed by rolling a sheet of a fiber aggregate, such as a woven fabric, nonwoven fabric, or knitted fabric, into a cylindrical shape to a predetermined thickness, preferably a cylindrical body formed by rolling a sheet of the fiber aggregate into a cylindrical shape so that multiple pleats are formed in the circumferential direction. The fibers constituting the fiber aggregate are not particularly limited and may be natural fibers, synthetic fibers, glass fibers, or a combination thereof. The mesh size (opening) of the filter element 41 is not particularly limited, but is set to a size suitable for capturing oil droplets in the liquid to be treated. The filter element 41 is not limited to the cylindrical body formed by the fiber aggregate described above, and various known filter elements conventionally used in this type of membrane separation device can be used.

[0032] The outer reinforcing member 42 has a cylindrical shape that is larger than the filter element 41. The filter element 41 is fitted into the outer reinforcing member 42, with the inner surface of the outer reinforcing member 42 contacting the outer surface of the filter element 41. The inner reinforcing member 43 has a cylindrical shape that is smaller than the filter element 41. The inner reinforcing member 43 is fitted into the filter element 41, with the outer surface of the inner reinforcing member 43 contacting the inner surface of the filter element 41. The two reinforcing members 42, 43 are made of, for example, metal, and have a plurality of through holes formed at equal intervals throughout their entire areas to allow the liquid to pass through.

[0033] The pair of cover members 44 are attached to both end portions of the filter element 41 and the two reinforcing members 42, 43. The pair of cover members 44 includes a disk-shaped covering portion 45 and a cylindrical fitting portion 46. With the end faces of the filter element 41 and the two reinforcing members 42, 43 abutting against the covering portion 45, the ends of the filter element 41 and the two reinforcing members 42, 43 are fitted inside the fitting portion 46, thereby uniting the filter element 41 and the two reinforcing members 42, 43 together with the pair of cover members 44. A communication hole 47 is formed in the center of the covering portion 45. The communication hole 47 connects the liquid flow paths 40 of two adjacent membrane cartridges 4 of the multiple membrane cartridges 4 connected in series.

[0034] The materials for the outer and inner reinforcing members 42, 43 and the pair of cover members 44 are not particularly limited, but metal or the like can be used.

[0035] Description of the first and second end plates As shown in Figures 4 to 9, the first end plate 5 is arranged at one end of the multiple membrane cartridges 4 connected in series, and the second end plate 6 is arranged at the other end of the multiple membrane cartridges 4 connected in series.

[0036] The first end plate 5 has a circular shape, and its diameter is larger than that of the membrane cartridge 4 and approximately the same as the diameter of the flange of the mounting part 23 of the sealed container 2. A plurality of through holes 50 are formed in the vicinity of the outer periphery of the first end plate 5 at equal intervals along the outer periphery. The first end plate 5 is fixed to the mounting part 23 by overlapping it with the flange of the mounting part 23 of the sealed container 2 and passing bolts (not shown) through the through holes 24, 50 of both plates and tightening them with nuts (not shown).

[0037] The second end plate 6 has a circular shape, and its diameter is larger than that of the membrane cartridge 4 but smaller than that of the first end plate 5. The second end plate 6 is connected to the first end plate 5 by a fixing means 9, which will be described later, with the plurality of membrane cartridges 4 connected in series sandwiched between the second end plate 6 and the first end plate 5. The plurality of membrane cartridges 4 connected in series are sandwiched between the first end plate 5 and the second end plate 6.

[0038] A pair of notches 60 are formed on the outer periphery of the second end plate 6. When attaching the filter unit 3 to the sealed container 2, the pair of notches 60 receive the corresponding guide rails 25 of the sealed container 2, allowing the filter unit 3 to be inserted into the sealed container 2 while the second end plate 6 slides on each guide rail 25, and also serves to restrict circumferential rotation of the filter unit 3. The notches 60 can have various shapes as long as they can fulfill the above-mentioned functions.

[0039] Handles 51, 61 are provided on the outer surfaces (the surfaces facing each other and the surfaces opposite each other) of the first end plate 5 and the second end plate 6, respectively. When attaching the filter unit 3 to the sealed container 2, an operator can grasp the handles 51, 61, which makes it easier to handle the filter unit 3 and perform the work.

[0040] A through-hole 52 is formed at the center of the first end plate 5. The diameter of the through-hole 52 is the same as or smaller than the inner diameter of the membrane cartridge 4. The through-hole 52 is formed in the first end plate 5 so as to be concentric with the liquid flow path 40. A circular cylindrical liquid guide portion 53 is provided on the outer surface of the first end plate 5 around the through-hole 52 so as to be concentric with the through-hole 52. The inner diameter of the liquid guide portion 53 is the same as or larger than the diameter of the through-hole 52.

[0041] In the filter unit 3, the liquid to be treated is introduced from the liquid guide portion 53 through the through-holes 52 into the liquid flow path 40 of the membrane cartridge 4 adjacent to the first end plate 5, and is then introduced into the liquid flow path 40 of each membrane cartridge 4 arranged in series, up to the liquid flow path 40 of the membrane cartridge 4 adjacent to the second end plate 6. The liquid to be treated then travels from the multiple through-holes in the inner reinforcing member 43 to the filter member 41, passes through the filter member 41 from the inner peripheral surface to the outer peripheral surface, and is then discharged from the multiple through-holes in the outer reinforcing member 42 into the sealed container 2 outside the membrane cartridge 4.

[0042] Gasket Description As shown in FIGS. 4 to 6, the gasket 7 is ring-shaped with an inner diameter larger than the inner diameter of the membrane cartridge 4 and an outer diameter the same as or smaller than the outer diameter of the membrane cartridge 4.

[0043] For each of the multiple membrane cartridges 4 connected in series, the gasket 7 is arranged on one end face of the membrane cartridge 4 (in this embodiment, the outer surface of one cover member 44) so ​​as to be concentric with the liquid flow path 40, and is fixed to the membrane cartridge 4. In addition, the gasket 7 is arranged on the inner surface of the first end plate 5 (the surface facing the second end plate 6) so as to be concentric with the through-hole 52 that is concentric with the liquid flow path 40, and is fixed to the first end plate 5. These multiple gaskets 7 seal the spaces (connections) between two adjacent membrane cartridges 4 of the multiple membrane cartridges 4 connected in series, as well as the spaces (connections) between the first end plate 5 and the second end plate 6 and the adjacent membrane cartridge 4, thereby suppressing leakage of the treated liquid from each liquid flow path 40 of the multiple membrane cartridges 4 connected in series to the outside of the membrane cartridge 4 without passing through the filter member 41 at each connection.

[0044] The gasket 7 is not particularly limited, and various known gaskets (for example, O-rings with a circular cross section, flat gaskets, etc.) used in this type of membrane separation device can be used.

[0045] Description of centering method As shown in Figures 4, 5, and 7 to 9, the centering means 8 aligns multiple membrane cartridges 4 connected in series between the first end plate 5 and the second end plate 6 so that the central axes of each liquid flow path 40 are aligned in the same straight line, in other words, so that the axial centers of the multiple membrane cartridges 4 are aligned. If multiple membrane cartridges 4 are connected in series with their axial centers misaligned, the gaskets 7 cannot accurately seal the connections, which can result in leakage of the treated liquid from the liquid flow paths 40. In this embodiment, when multiple membrane cartridges 4 are connected in series, the centering means 8 aligns the membrane cartridges 4 so that their axial centers are aligned, thereby improving the sealing accuracy of the gaskets 7 at the connections and suppressing leakage of the treated liquid from the liquid flow paths 40.

[0046] In this embodiment, the centering means 8 is composed of at least three (four in this embodiment) rod-shaped members 80 extending from the first end plate 5 to the second end plate 6. The at least three rod-shaped members 80 are parallel to one another. A male thread (not shown) is formed on the outer circumferential surface of one end of each rod-shaped member 80.

[0047] On the inner surface of the first end plate 5, at positions that will form the periphery of the membrane cartridge 4, a plurality (four in this embodiment) of cylindrical connecting portions 81, each having an internal thread (not shown) formed on its inner circumferential surface, are provided at intervals along the circumferential direction of the membrane cartridge 4. One end of a rod-shaped member 80 is connected to the connecting portion 81 of the first end plate 5 by screw connection, so that the rod-shaped member 80 extends from the first end plate 5. The rod-shaped member 80 may be provided to the first end plate 5 by welding or the like without using the connecting portion 81, or may be formed integrally with the first end plate 5. A plurality (four in this embodiment) of through-holes (not shown) are formed in the second end plate 6 at positions that will form the periphery of the membrane cartridge 4 and that face the plurality of connecting portions 51 of the first end plate 5, at intervals along the circumferential direction of the membrane cartridge 4.

[0048] The multiple rod-shaped members 80 are arranged at equal intervals on an imaginary circle concentric with the through-hole 52 of the first end plate 5. The multiple rod-shaped members 80 are arranged around the membrane cartridge 4, but are arranged in close proximity to the membrane cartridge 4. Note that "close" refers to a state in which the rod-shaped members 80 are in contact with at least a part of the membrane cartridge 4, or a state in which they are not in direct contact but are located very close to the membrane cartridge 4 with a small gap therebetween.

[0049] Using the four rod-shaped members 80 extending from the first end plate 5 as guides, the multiple membrane cartridges 4 are inserted into the inner region of the four rod-shaped members 80, and then the other ends of the four rod-shaped members 80 are passed through four through-holes (not shown) in the second end plate 6 to sandwich the multiple membrane cartridges 4 between the second end plate 6 and the first end plate 5. This allows the multiple membrane cartridges 4 to be connected in series with their axes aligned, and the gaskets 7 interposed at the connection portions of the multiple membrane cartridges 4 connected in series are disposed in appropriate positions that allow for accurate sealing at the connection portions. Therefore, the gaskets 7 accurately seal the connection portions, thereby preventing leakage of the treated liquid from the liquid flow paths 40. Note that the gaskets 7 are also disposed in appropriate positions that allow for accurate sealing at the connection portions between the first end plate 5 and the second end plate 6 and the adjacent membrane cartridges 4, so that the gaskets 7 accurately seal the connection portions as well, preventing leakage of the treated liquid from the liquid flow paths 40.

[0050] Description of fixing means 4, 5, and 7 to 9, the fixing means 9 fixes the second end plate 6 in a state where it is pressed against the first end plate 5, and holds the plurality of membrane cartridges 4 connected in series between the first end plate 5 and the second end plate 6. In this embodiment, the fixing means 9 is composed of a plurality of (four in this embodiment) rod-shaped members 80 that constitute the centering means 8 described above, and a plurality of (four in this embodiment) fixing devices 90 that fix the second end plate 6 pressed against the first end plate 5 to the plurality of rod-shaped members 80.

[0051] The rod-shaped member 80 has a male thread (not shown) formed on its outer surface at the other end opposite to the one end connected to the connecting portion 81 of the first end plate 5, and the other end passes through a through-hole (not shown) in the second end plate 6 and protrudes from the second end plate 6. A fixing device 90 such as a nut is attached to the other end of the rod-shaped member 80 protruding from the second end plate 6, and the second end plate 6 is fastened to the first end plate 5 side by the fixing device 90. As a result, the second end plate 6 is fixed to the multiple rod-shaped members 80 with the multiple membrane cartridges 4 connected in series pressed against the first end plate 5 side, and the multiple membrane cartridges 4 connected in series are held between the first end plate 5 and the second end plate 6.

[0052] The material of the rod-shaped member 80 is not particularly limited, but metal, etc., can be used. The fixing device 90 does not necessarily have to be a nut, and various known devices can be used as long as they can fix the second end plate 6 to the rod-shaped member 80 while pressing it against the first end plate 5.

[0053] Explanation of how to install the filter unit in a sealed container First, the filter unit 3 is assembled. The multiple membrane cartridges 4 are aligned in series by positioning and setting them one by one on the first end plate 5 using the multiple rod-shaped members 80 as guides. Then, the second end plate 6 is positioned and set on the first end plate 5 by passing the other ends of the multiple rod-shaped members 80 through its multiple through-holes (not shown), and the multiple membrane cartridges 4 are sandwiched between the first end plate 5 and the second end plate 6. Then, fasteners 90 are attached to the other ends of the multiple rod-shaped members 80, and the second end plate 6 is fixed to the multiple rod-shaped members 80 while fastening the second end plate 6 to the first end plate 5 with the fasteners 90. This holds the multiple membrane cartridges 4 between the first end plate 5 and the second end plate 6.

[0054] Next, the filter unit 3 is inserted into the sealed container 2 from the mounting portion 23. At this time, the second end plate 6 is placed on the pair of guide rails 25 so that the guide rails 25 fit into the pair of notches 51 in the second end plate 6, and the filter unit 3 is pushed in while the second end plate 6 is slid on the pair of guide rails 25. This makes it easier to insert the filter unit 3 into the sealed container 2 from the mounting portion 23. Then, by fixing the first end plate 5 to the flange of the mounting portion 23, the filter unit 3 is attached to the sealed container 2 in a horizontal orientation with the liquid flow paths 40 of each membrane cartridge 4 extending horizontally.

[0055] Explanation of the effects of the oil-water separation device (one embodiment of the membrane separation device) According to the oil-water separation device 1 of the present embodiment described above, since multiple membrane cartridges 4 can be attached to the sealed container 2, the membrane area per unit installation area of ​​the device can be increased. This allows for improved oil separation performance in the oil-water separation device 1. Furthermore, since multiple membrane cartridges 4 are connected in series, the device shape can be made more compact than when they are arranged in parallel. This allows for a reduction in the floor space occupied by the device. Furthermore, since multiple membrane cartridges 4 can be collectively attached and detached to and from the sealed container 2 during device maintenance, etc., this makes the work easier and reduces the effort and time required for the work.

[0056] Furthermore, according to the oil-water separation device 1 of this embodiment, when connecting multiple membrane cartridges 4 in series, the centering means 8 can be used to align the multiple membrane cartridges 4 with their respective axial centers aligned, and the fixing means 9 can hold the multiple membrane cartridges 4 in this aligned state. Therefore, by previously disposing the gasket 7 in an appropriate position that can achieve the desired seal for each membrane cartridge 4, it is possible to suppress leakage of the treated liquid from each liquid flow path 40 at the connection portion between two adjacent membrane cartridges 4 of multiple membrane cartridges 4 connected in series.

[0057] Description of variants Although one embodiment of the membrane separation device of the present disclosure has been described above, the membrane separation device of the present disclosure is not limited to the above embodiment, and various modifications are possible without departing from the spirit of the present disclosure. Note that in other embodiments of the membrane separation device of the present disclosure described below, the same components as those in the above embodiment are designated by the same reference numerals, and detailed descriptions thereof will be omitted.

[0058] For example, in the above embodiment, the multiple rod-shaped members 80 connecting the first end plate 5 and the second end plate 6 are arranged close to the periphery of the multiple membrane cartridges 4 connected in series, thereby aligning the multiple membrane cartridges 4 connected in series by the multiple rod-shaped members 80. In another embodiment, the multiple rod-shaped members 80 are arranged spaced apart from each other around the multiple membrane cartridges 4 connected in series, and the multiple rod-shaped members 80 simply connect the first end plate 5 and the second end plate 6, without aligning the multiple membrane cartridges 4 connected in series, and a separate member for aligning the multiple membrane cartridges 4 connected in series may be used. In other words, the multiple rod-shaped members 80 may constitute the fixing means 9 but not the centering means 8, and a separate member may constitute the centering means 8.

[0059] 10 and 11, for example, a connector 82 can be interposed between two adjacent membrane cartridges 4 of a plurality of membrane cartridges 4 connected in series, and at least one connector 82 can be used as a component of the centering means 8. The connector 82 includes a cylindrical portion 83 that is inserted into each liquid flow path 40 of the two adjacent membrane cartridges 4, and a protruding portion 84 that protrudes from the outer peripheral surface of the cylindrical portion 83 and is sandwiched between the two adjacent membrane cartridges 4. The material of the connector 82 is not particularly limited, and metal, synthetic resin, hard rubber, etc. can be used.

[0060] The tubular part 83 has a cylindrical shape with an outer diameter that is the same as or slightly smaller than the inner diameter of the membrane cartridge 4. The tubular part 83 is fitted into the membrane cartridge 4 at the end of the membrane cartridge 4, and its hollow interior connects the liquid flow paths 40 of two adjacent membrane cartridges 4. There are no particular limitations on the thickness or length of the tubular part 83 as long as it can be fitted into the membrane cartridge 4, but a thinner thickness is preferable as long as the strength is sufficient.

[0061] The protruding portion 84 has a disk shape with an outer diameter that is larger than the inner diameter of the membrane cartridge 4 and smaller than the inner diameter of the gasket 7. The protruding portion 84 abuts against the end face of the membrane cartridge 4, thereby holding the connector 82 in a fixed position between two adjacent membrane cartridges 4. The thickness and outer diameter of the protruding portion 84 are not particularly limited as long as it can be sandwiched between two adjacent membrane cartridges 4, but a thinner thickness is preferable as long as the strength is sufficient. Note that the protruding portion 84 does not necessarily have to be a disk, and multiple plate-like portions (not shown) may protrude from the outer circumferential surface of the cylindrical portion 83 at equal intervals in the circumferential direction.

[0062] 10 and 11, when connecting multiple membrane cartridges 4 in series, the multiple membrane cartridges 4 can be aligned with their respective axial centers aligned using the connectors 82, and the multiple membrane cartridges 4 can be held in this aligned state using the fixing means 9. Therefore, by previously disposing the gaskets 7 in appropriate positions that can achieve the desired seal for each membrane cartridge 4, leakage of the treated liquid from each liquid flow path 40 at the connection portion between two adjacent membrane cartridges 4 of multiple membrane cartridges 4 connected in series can be suppressed.

[0063] 12 to 14, a cylindrical guide 85 can be integrally formed on the inside of a gasket 7 interposed between two adjacent membrane cartridges 4 of a plurality of membrane cartridges 4 connected in series, and at least one guide 85 can be used as a component of the centering means 8. The guide 85 is inserted into the gasket 7 of the two adjacent membrane cartridges 4 and the liquid flow path 40 of the membrane cartridge 4 to which the guide 85 is not attached.

[0064] The guide 85 has a cylindrical shape with an outer diameter that is the same as or slightly smaller than the inner diameter of the membrane cartridge 4. The guide 85 is fitted into the membrane cartridge 4 at the end of the membrane cartridge 4, and its hollow interior connects the liquid flow paths 40 of two adjacent membrane cartridges 4. There are no particular limitations on the thickness or length of the guide 85 as long as it can be fitted into the membrane cartridge 4, but a thinner thickness is preferable as long as the strength is sufficient.

[0065] 12 to 14, when connecting multiple membrane cartridges 4 in series, the guides 85 can be used to align the multiple membrane cartridges 4 with their respective axial centers aligned, and the fixing means 9 can hold the multiple membrane cartridges 4 in this aligned state. Therefore, by previously disposing the gaskets 7 in appropriate positions that can achieve the desired seal for each membrane cartridge 4, leakage of the treated liquid from each liquid flow path 40 at the connection portion between two adjacent membrane cartridges 4 of multiple membrane cartridges 4 connected in series can be suppressed.

[0066] 12 to 14, a guide 85 is integrally formed with the gasket 7 attached to the inner surface of the first end plate 5 and the gasket 7 attached to the end surface of the membrane cartridge 4 adjacent to the second end plate 6. The guide 85 of the gasket 7 attached to the first end plate 5 is cylindrical and has an outer diameter smaller than the inner diameter of the membrane cartridge 4. It is arranged on the inner surface of the first end plate 5 so as to be concentric with the through-hole 52 that is concentric with the liquid flow path 40, and is inserted into the liquid flow path 40 of the membrane cartridge 4 adjacent to the first end plate 5. A recess 63 is formed on the inner surface of the second end plate 6 (the surface facing the first end plate 5). The guide 85 of the gasket 7 attached to the membrane cartridge 4 adjacent to the second end plate 6 is cylindrical and has an outer diameter smaller than the diameter of the recess 63. It is arranged on the end surface of the membrane cartridge 4 so as to be concentric with the liquid flow path 40, and is inserted into the recess 63 of the second end plate 6. However, the gasket 7 attached to the first end plate 5 and the gasket 7 attached to the membrane cartridge 4 adjacent to the second end plate 6 do not necessarily need to have the guide 85 formed integrally therewith.

[0067] 15 to 18, a connecting pipe 86 may be provided on the end face of one of two adjacent membrane cartridges 4 among a plurality of membrane cartridges 4 connected in series so as to protrude from the end face, and at least one connecting pipe 86 may be used as a component of the centering means 8. The connecting pipe 86 is inserted into the liquid flow path 40 of the membrane cartridge 4 that is not provided with the connecting pipe 86 of the two adjacent membrane cartridges 4.

[0068] The connecting pipe 86 has a cylindrical shape with an outer diameter smaller than the inner diameter of the membrane cartridge 4. The connecting pipe 86 is arranged concentrically with the liquid flow path 40 on the end face of the membrane cartridge 4. A ring-shaped gasket 7 is attached to the outer peripheral surface of the connecting pipe 86. The connecting pipe 86 is fitted into the interior of the membrane cartridge 4 at the end of the membrane cartridge 4 via the gasket 7, and connects the liquid flow paths 40 of two adjacent membrane cartridges 4 via its hollow interior. The thickness and length of the connecting pipe 86 are not particularly limited as long as it can be fitted into the interior of the membrane cartridge 4, but a thinner thickness is preferable as long as the strength is sufficient. The material of the connecting pipe 86 is not particularly limited, but metal, synthetic resin, hard rubber, etc. can be used.

[0069] 15 to 18, when connecting multiple membrane cartridges 4 in series, the connecting pipe 86 can be used to align the multiple membrane cartridges 4 with their respective axial centers aligned, and the fixing means 9 can hold the multiple membrane cartridges 4 in this aligned state. Therefore, by previously disposing the gasket 7 in an appropriate position that can achieve the desired seal for each membrane cartridge 4, leakage of the treated liquid from each liquid flow path 40 at the connection portion between two adjacent membrane cartridges 4 of multiple membrane cartridges 4 connected in series can be suppressed.

[0070] 15 to 18, connecting pipes 86 are also provided on the inner surface of the first end plate 5 and on the end surface of the membrane cartridge 4 adjacent to the second end plate 6, and a ring-shaped gasket 7 is attached to the outer peripheral surface of the connecting pipe 86. The connecting pipe 86 provided on the first end plate 5 is cylindrical and has an outer diameter smaller than the inner diameter of the membrane cartridge 4. It is arranged on the inner surface of the first end plate 5 so as to be concentric with the through-hole 52 that is concentric with the liquid flow path 40, and is inserted into the liquid flow path 40 of the membrane cartridge 4 adjacent to the first end plate 5 via the gasket 7. A recess 63 is formed on the inner surface of the second end plate 6. The connecting pipe 86 provided on the membrane cartridge 4 adjacent to the second end plate 6 is cylindrical and has an outer diameter smaller than the diameter of the recess 63. It is arranged on the end surface of the membrane cartridge 4 so as to be concentric with the liquid flow path 40, and is inserted into the recess 63 of the second end plate 6 via the gasket 7. However, the membrane cartridges 4 adjacent to the first end plate 5 and the second end plate 6 do not necessarily need to be provided with the connecting pipes 86 .

[0071] 15 to 18, the ring-shaped gasket 7 is attached to the outer peripheral surface of the connecting pipe 86, but similarly to the above-described embodiment, it may also be attached to the inner surface of the first end plate 5 and the end surface of the membrane cartridge 4. In this case, the connecting pipe 86 has a cylindrical shape whose outer diameter is the same as or slightly smaller than the inner diameter of the membrane cartridge 4.

[0072] 19 to 22, an inner pipe 87 extending toward the second end plate 6 can be provided on the first end plate 5, and the inner pipe 87 can be used as a component of the centering means 8. The inner pipe 87 is inserted into each liquid flow path 40 of multiple membrane cartridges 4 connected in series. The inner pipe 87 has a cylindrical shape with an outer diameter that is the same as or slightly smaller than the inner diameter of the membrane cartridge 4.

[0073] The thickness and length of the inner tube 87 are not particularly limited as long as it can be fitted inside the multiple membrane cartridges 4 connected in series, but a thinner thickness is preferable as long as the strength is sufficient. The material of the inner tube 87 is not particularly limited, but metal, synthetic resin, hard rubber, etc. can be used.

[0074] The inner pipe 87 is arranged around the through hole 52 on the inner surface of the first end plate 5 so as to be concentric with the through hole 52. The end of the inner pipe 87 facing the first end plate 5 is open, and this opening is adjacent to the through hole 52 in the first end plate 5 and communicates with the liquid guide section 53. The end of the inner pipe 87 facing the second end plate 6 is closed, and the end facing the second end plate 6 is located in the vicinity of the second end plate 6. A plurality of liquid passage holes 88 are formed in the peripheral wall of the inner pipe 87 at intervals along the axial and circumferential directions. The liquid to be treated is introduced into the inner pipe 87 from the liquid guide section 53 through the opening at the end of the inner pipe 87 facing the first end plate 5, and is supplied to the filter member 40 of the membrane cartridge 4 around the inner pipe 87 through the plurality of liquid passage holes 88.

[0075] 19 to 22, when connecting multiple membrane cartridges 4 in series, the multiple membrane cartridges 4 can be aligned with their respective axial centers aligned by the inner tube 87, and the multiple membrane cartridges 4 can be held in this aligned state by the fixing means 9. Therefore, by previously disposing the gasket 7 in an appropriate position that can achieve the desired seal for each membrane cartridge 4, leakage of the treated liquid from each liquid flow path 40 at the connection portion between two adjacent membrane cartridges 4 of multiple membrane cartridges 4 connected in series can be suppressed.

[0076] In the embodiments shown in Figures 19 to 22, the fixing means 9 can have as its components multiple rod-shaped members 80 and multiple fixing devices 90, as in the above embodiments, but instead, the fixing means 9 may have as its components at least one (one in this embodiment) rod-shaped member 91 protruding from the end face of the inner tube 87 on the side of the second end plate 6, and at least one (one in this embodiment) fixing device 92 that fixes the second end plate 6 pressed against the side of the first end plate 5 to the rod-shaped member 91.

[0077] The rod-shaped member 91 passes through a through-hole 64 at the center of the second end plate 6 and its tip protrudes from the second end plate 6, and a male thread 93 is formed on the outer peripheral surface of the tip protruding from the second end plate 6. A fixing device 92 such as a nut is attached to the tip of the rod-shaped member 91, and the second end plate 6 is fastened to the first end plate 5 side by the fixing device 92. As a result, the second end plate 6 is fixed to the rod-shaped member 91 with the multiple membrane cartridges 4 connected in series pressed against the first end plate 5 side, and the multiple membrane cartridges 4 connected in series are held between the first end plate 5 and the second end plate 6.

[0078] The material of the rod-shaped member 91 is not particularly limited, but metal, etc., can be used. The fastener 92 does not necessarily have to be a nut, and various known fasteners can be used as long as they can fasten the second end plate 6 to the rod-shaped member 91 while pressing it against the first end plate 5.

[0079] It should be noted that the centering means 8 and the fixing means 9 in all the above-described embodiments are merely examples, and the centering means 8 and the fixing means 9 are not limited to the configurations shown as examples.

[0080] In another embodiment, although not shown, the filter unit 3 can be attached to the sealed container 2 in a vertical orientation in which the liquid flow paths 40 of each membrane cartridge 4 extend vertically.

[0081] In another embodiment, although not shown, a plurality of attachment portions 23 can be provided on the sealed container 2, and a plurality of filter units 3 can be attached to the sealed container 2 in parallel. [Explanation of symbols]

[0082] 1 Oil / water separator (membrane separator) 2. Airtight containers 3 Filter Unit 4 membrane cartridges 5 First end plate 6 Second end plate 7 Gasket 8 Centering means 9 Fixing means 40 Liquid flow path 80 Rod-shaped member 82 Connector 83 Cylindrical part 84 Protrusion 85 Guide 86 Connecting pipe 87 Inner tube 88 Liquid passage hole 90 Fixtures 91 Rod-shaped members 92 Fixtures

Claims

1. An oil-water separator for separating oil from a liquid, comprising: A sealed container and a filter unit; The filter unit comprises: A plurality of membrane cartridges each having a cylindrical shape and having a liquid flow path therein, and attached to the sealed container in a serially connected state; a first end plate and a second end plate disposed at both ends of the plurality of membrane cartridges connected in series; At least one ring-shaped gasket attached to one of two adjacent membrane cartridges of the plurality of membrane cartridges connected in series to seal the connection portion of the two adjacent membrane cartridges; a centering means for aligning the plurality of membrane cartridges connected in series so that the central axes of the liquid flow paths are aligned in the same straight line; a fixing means for fixing the second end plate in a state where the second end plate is pressed against the first end plate, and for sandwiching and holding the plurality of membrane cartridges connected in series between the first end plate and the second end plate; The filter unit can be inserted into and removed from the sealed container sideways, the liquid is supplied into the filter unit from a liquid guide portion of the filter unit, passes through the filter unit, and is then supplied into the sealed container; The sealed container is provided with a first discharge section for discharging, from the sealed container, oil that has risen to the surface and separated from the liquid that has passed through the filter unit, a second discharge section for discharging, from the sealed container, the liquid from which the oil has separated and whose oil concentration has decreased, and a third discharge section for discharging, from the sealed container, drain that has settled at the bottom of the sealed container, An oil-water separation device, wherein the first discharge section is provided above the filter unit, and the second and third discharge sections are provided below the filter unit.

2. the first end plate is provided with at least three rod-shaped members extending parallel to one another toward the second end plate, the at least three rod-shaped members constituting the centering means; At least three of the rod-shaped members are arranged at equal intervals in the circumferential direction on the first end plate so as to be close to the periphery of the plurality of membrane cartridges connected in series, The oil-water separation device of claim 1, wherein the fixing means is composed of the rod-shaped member and a fixing device that fixes the second end plate pressed against the first end plate to the rod-shaped member.

3. an inner tube is provided on the first end plate, extending toward the second end plate and inserted into the interiors of the plurality of membrane cartridges connected in series, the inner tube constituting the centering means; An oil-water separation device as described in claim 1, wherein the inner tube has an open end on the first end plate side and a closed end on the second end plate side, and has a plurality of liquid-passing holes formed in its peripheral wall, and liquid is introduced into the interior through the openings.

4. a rod-shaped member that penetrates the second end plate projects from an end surface of the inner tube on the second end plate side; The oil-water separation device of claim 3, wherein the fixing means is composed of the rod-shaped member and a fixing device that fixes the second end plate pressed against the first end plate to the rod-shaped member.

5. A connector is interposed between two adjacent membrane cartridges of the plurality of membrane cartridges connected in series, and at least one of the connectors constitutes the centering means; The oil-water separation device described in claim 1, wherein the connecting device includes a cylindrical portion that is inserted into the interior of two adjacent membrane cartridges, and a protruding portion that protrudes from the outer surface of the cylindrical portion and is sandwiched between the two adjacent membrane cartridges.

6. The gasket is attached to an end surface of one of two adjacent membrane cartridges of the plurality of membrane cartridges connected in series, A cylindrical guide is integrally formed inside the gasket, and at least one of the guides constitutes the centering means; The oil-water separation device according to claim 1 , wherein the guide is inserted into the other of the two adjacent membrane cartridges.

7. A connecting pipe protrudes from an end surface of one of two adjacent membrane cartridges of the plurality of membrane cartridges connected in series, and at least one of the connecting pipes constitutes the centering means; The oil-water separation device according to claim 1 , wherein the connecting pipe is inserted into the other of the two adjacent membrane cartridges.

8. The oil-water separation device according to claim 7 , wherein the gasket is provided between an outer peripheral surface of the connecting pipe and an inner peripheral surface of the membrane cartridge into which the connecting pipe is fitted.

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