JP4484685B2 - Spiral separation membrane element and manufacturing apparatus thereof - Google Patents

Description

  The present invention relates to a spiral separation membrane element that uses a separation membrane to separate components of a fluid by a reverse osmosis technique, a filtration technique, and the like, and an apparatus for manufacturing the same.

  Conventionally, many filtration devices have been used for wastewater treatment or purified water supply in factories and buildings. In particular, advanced microfiltration devices are required for treated water in semiconductor manufacturing processes in recent years, and microfiltration membranes (MF membranes), ultrafiltration membranes (UF membranes), and reverse osmosis membranes (RO membranes) are used. Spiral type separation membrane elements (hereinafter referred to as membrane elements) are frequently used.

  As a structure of such a membrane element, a plurality of separation membranes 2, a supply-side channel material 6 and a permeation-side channel material 3 shown in FIG. 1 are wound around a perforated hollow central tube 5 in a spiral shape. A membrane element 1 is known. In the membrane element 1, the stock solution 7 is supplied from one end surface, and the concentrated solution 9 is taken out from the other end surface. While the stock solution 7 is guided to the supply-side channel material 6, the permeate 8 filtered by the separation membrane 2 passes through the permeation-side channel material 3 and is taken out through the hole of the hollow central tube 5. In the case of back-flow cleaning using a permeate or cleaning liquid, the back-flow cleaning liquid is supplied to the central tube 5 in a dispersed manner, dispersedly supplied from the holes, cleaned from the back side of the separation membrane 2 and discharged as cleaning waste water (for example, Patent Document 1).

  Here, the winding of the separation membrane 2 or the like around the central tube 5 is performed, for example, by inserting a drive shaft into the central tube 5 and rotating the drive shaft while applying tension to the separation membrane 2 or the like.

  However, if the inner shape of the center tube 5 is circular, if the tension is greater than the frictional force generated between the inner wall surface of the center tube 5 and the drive shaft, slip occurs between the two. As a result, there has been a problem that the drive shaft is scratched on the inner wall surface of the central tube 5.

Further, since the separation membrane 2 and the like cannot be pulled with sufficient tension, a gap is generated particularly near the central tube 5. When the membrane element 1 is housed in a housing or the like, the size of the membrane element needs to be suppressed as much as possible due to space limitations of the housing and the like. However, if the winding is such that a gap is generated as described above, it is not possible to wind a separation membrane having a larger membrane area within the range that can be accommodated in a housing or the like, and thus the membrane area is large and the separation performance is excellent. There was also a problem that it was difficult to obtain a membrane element.
JP 10-137558 A

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a spiral separation membrane element capable of expanding an effective membrane area and improving separation performance, and a manufacturing apparatus thereof. is there.

  In order to solve the above-described conventional problems, the inventors of the present application have made extensive studies on a spiral separation membrane element and a manufacturing apparatus therefor. As a result, the inventors have found that the object can be achieved by adopting the following configuration, and have completed the present invention.

That is, in order to solve the above-described problem, the spiral separation membrane element according to the present invention is formed by alternately stacking separation membrane units and permeation side flow passage materials in which supply side flow passage materials are arranged between separation membranes. In a spiral separation membrane element in which a laminate is wound around a perforated hollow central tube, the outer shape of the central tube is circular in cross section, and the inner wall surface at the end of the central tube is The cross section has a circular shape, and the other inner wall surface has an elliptical shape in its cross section, and has a shape that allows insertion of a drive shaft having an elliptical outer shape that can lock relative rotation. Features.

In addition, in order to solve the above-described problems, the manufacturing apparatus for a spiral separation membrane element according to the present invention alternately includes a separation membrane unit in which a supply-side channel material is disposed between separation membranes and a permeation-side channel material. In the manufacturing apparatus of the spiral separation membrane element provided with means for winding the laminated body on the periphery of the perforated hollow central tube,
A drive shaft for inserting the inside of the central tube to rotate the central tube and winding the laminate around the central tube;
The outer shape is circular in the cross section, the inner wall surface of the end portion has a circular shape in the cross section, and the other inner wall surfaces can lock relative rotation with respect to the central tube having the elliptical shape in the cross section. A drive shaft having an elliptical outer shape is provided.

  The present invention has the following effects by the means described above.

  That is, according to the spiral-type separation membrane element of the present invention, the inner wall surface of the center tube has a shape that allows insertion of a drive shaft having an outer shape that can lock relative rotation. When the central tube is rotated and the laminate is wound, the inner wall surface of the central tube can be prevented from being damaged. Furthermore, it is possible to wind the laminated body with a large tension, and it is possible to apply a driving force uniformly in the longitudinal direction of the water collecting pipe, which causes wrinkles in the laminated body or the central pipe. It is also possible to eliminate the occurrence of a gap at the winding start portion. As a result, a separation membrane having as large an area as possible can be wound around the central tube while suppressing an increase in size, and a spiral separation membrane element having excellent separation performance can be provided.

  Further, according to the spiral separation membrane element manufacturing apparatus according to the present invention, since the drive shaft having an outer shape capable of locking relative rotation is provided inside the central tube in the spiral separation membrane element, When the laminate is wound around the central tube, it can be rotated without damaging the inner wall surface of the central tube. In addition, the laminate can be wound while applying a large tension. As a result, it is possible to manufacture a separation membrane having as large an area as possible around the central tube while preventing gaps and wrinkles from occurring in the laminate and suppressing an increase in size. Therefore, according to this invention, the manufacturing apparatus which can manufacture the spiral-type separation membrane element excellent in the separation performance can be provided.

  Embodiments of the present invention will be described below with reference to the drawings. The spiral type separation membrane element (hereinafter referred to as membrane element) according to the present invention is different from the conventional one only in the shape of the inner surface of the central tube, and the other structure applies the configuration of the conventional membrane element described above. be able to. Therefore, here, an example of the configuration of the membrane element according to the present embodiment will be described with reference to FIG. 1 again.

  As shown in FIG. 1, the membrane element 1 according to the present embodiment has an envelope-like membrane by superposing separation membranes 2 on both surfaces of a permeation-side flow path material 3 made of a synthetic resin net and adhering three sides. (Bag-like membrane) 4 is formed, and the opening of the envelope-like membrane 4 is attached to the central tube 5 and spirally wound around the outer peripheral surface of the central tube 5 together with the supply-side flow path member 6 made of a synthetic resin net. It is constituted by doing.

  The separation membrane 2 has a structure in which, for example, a porous support and a skin layer (dense layer) are sequentially laminated on a nonwoven fabric layer. It does not specifically limit as a constituent material of a nonwoven fabric layer, A conventionally well-known thing is employable.

  As the constituent material of the porous support, conventionally known materials can be employed. Specifically, for example, polyarylethersulfone such as polysulfone and polyethersulfone, polyimide, polyvinylidene fluoride and the like can be exemplified.

  The skin layer has a separation function that does not exhibit permeability to the separation target substance contained in the fluid. The material constituting the skin layer is not particularly limited, and conventionally known materials can be adopted. Specific examples include PE, PP, PET, nylon, polyamide, polyacrylonitrile (PAN), polyvinyl alcohol (PVA), PMMA, polysulfone, polyethersulfone, polyimide, and ethylene-vinyl alcohol copolymer. it can.

  For the supply-side channel material 6, a net-like material, a mesh-like material, a grooved sheet, a corrugated sheet or the like can be used. For the permeate-side channel material 3, a net-like material, a knitted material, a mesh-like material, a grooved sheet, a corrugated sheet, or the like can be used.

  As shown in FIG. 2, the central tube 5 has a structure having a plurality of openings around the tube. The inner wall surface 10 of the central tube 5 has a regular hexagonal shape in its cross section, and has a shape that allows insertion of a drive shaft, which will be described later. With such an inner wall surface 10, the force transmitted to the central tube 5 by the rotation of the drive shaft pushes the inner wall surface 10 of the central tube 5 toward the direction (winding direction) in which it is intended to rotate. It becomes power. This force becomes a driving force for rotating the central tube 5. On the other hand, in the conventional circular shape, the driving force for rotating the center tube 5 is only the friction force generated on the contact surface between the inner wall of the center tube 5 and the drive shaft. In this case, if tension is applied to the separation membrane 2 or the like to be wound, slippage often occurs between the inner wall surface 10 of the central tube 5 and the drive shaft. As a result, the inner wall surface 10 is damaged or the vicinity of the central tube 5 For example, a gap may be generated between the stacked bodies. In addition, it is preferable that the shape in the cross section of the inner wall surface 10 of the center tube 5 is the same in the axial direction.

  Here, the cross-sectional shape of the central tube 5 is not limited to the shape shown in FIG. 2, but may be, for example, an elliptical inner wall surface 11 shown in FIG. 3 or a rectangular inner wall surface 12 shown in FIG. it can. Moreover, as shown to Fig.5 (a), the edge part of the center pipe | tube 5 is good also as a structure which has the circular inner wall surface 13, and the other part has the inner wall surface 14 of a regular hexagon. Furthermore, it may be a regular hexagonal inner wall surface 15 shown in FIG. Further, the center tube 5 may be one in which a groove is provided in a part of a circular inner wall surface or one in which a ridge portion extending in parallel with the axial direction is provided. Further, when the drive shaft is a spline shaft, the center tube 5 may be provided with an inner wall surface in which at least four or more key grooves are formed in the axial direction. With such a shape, a larger rotational force can be transmitted to the central tube 5. That is, in the present invention, the inner wall surface of the center tube 5 is not only subjected to a driving force for rotating the inner tube 5 but also a friction force generated between the center tube 5 and the drive shaft, and a force pushing toward the winding direction side. There is no particular limitation as long as it is added to at least a part of the wall surface.

  From the viewpoint of preventing the rotation of the central tube 5, for example, an aspect in which the outer shape is simply made into a rectangular shape or a protrusion is provided is also conceivable. However, these shapes have the disadvantage that the laminate cannot be wound in a circular shape, resulting in a distorted membrane element.

  The constituent material of the central tube 5 is not particularly limited, and a conventionally known resin or the like can be employed. In addition, the length, outer diameter, inner diameter, and the like of the center tube 5 can be changed as appropriate according to the application. Furthermore, a conventionally well-known method can be adopted as a method for manufacturing the center tube 5.

  The membrane element manufacturing apparatus according to the present embodiment includes a drive shaft that is inserted into the center tube 5 and rotated, and the laminate is wound around the center tube 5. The outer shape of the drive shaft preferably matches the shape and size of the inner wall surface of the central tube 5. This is because the rotational force of the drive shaft is effectively transmitted to the central tube 5. Therefore, when the inner wall surface of the center tube 5 has an elliptical shape or a regular square shape as shown in FIGS. 2 and 3 in its cross section, the outer shape of the drive shaft is also preferably an elliptical shape or a rectangular shape. . Moreover, as a drive shaft, a part provided with a ridge extending in parallel to the axial direction in a part of a circular outer shape, a part provided with a groove, a spline shaft, or the like can be adopted. . However, in the present invention, the outer shape of the drive shaft is not limited to the above case, and a structure that can lock relative rotation with the inner wall surface of the central tube 5 by, for example, a shape other than a substantially circular shape. Then, it is not always necessary to match the shape of the inner wall surface.

  The constituent material of the drive shaft is not particularly limited, and a conventionally known material such as a steel material can be employed. The drive shaft is driven by a conventionally known drive device such as a drive motor (not shown).

  In addition, the membrane element manufacturing apparatus according to the present embodiment preferably includes means for applying tension to the end of the outermost layered laminate among the laminates being wound around the central tube 5. As a result, the laminate can be wound without any gap even in the vicinity of the central tube 5. As a result, the separation membrane 2 having a larger area compared to the conventional membrane element is within the same size as the conventional membrane element. It becomes possible to wind with. As a result, the membrane effective area can be increased, and a membrane element having excellent separation performance can be produced.

  Here, the means is not particularly limited, and examples thereof include a nip roll capable of gripping the end of the laminated body and applying a tension. Moreover, it is preferable that the tension applied to the laminate is appropriately set according to the driving force of the driving motor. Specifically, for example, it is preferably within a range of 2 to 5 N / element width.

  Incidentally, in the membrane element manufacturing apparatus according to the present invention, conventionally known ones can be adopted for the other configurations.

  Further, as shown in FIGS. 6A to 6D, the central tube 5 is axially rotated on the surface of the membrane element 1 using a drive shaft, and a sheet-like outer peripheral tape 20 is placed on the surface of the membrane element 1. It may be wound. Even in such a case, since the inner wall surface of the center tube 5 has a shape that allows insertion of a drive shaft having an outer shape capable of locking relative rotation, the inner wall surface of the center tube 5 is prevented from being damaged. be able to. The tape tension applied to the outer peripheral tape 20 is preferably in the range of 10 to 20 kgf / 75 mm (0.13 to 0.27 kgf / mm, 1.31 to 2.65 N / mm). FIGS. 4A to 4D show a case in which the outer peripheral tape 20 having a predetermined width is spirally wound toward the end in the axial direction, and then spirally wound toward the other end in the axial direction. An example of spiral winding toward the center of the direction is shown. That is, the outer peripheral tape 20 is spirally wound around each part of the membrane element 1 for two layers. The winding direction of the outer peripheral tape 20 is the same as the winding direction of the laminate in the membrane element 1.

  As shown in FIG. 6A, the tip of the outer peripheral tape 20 is fixed at the winding start position of the membrane element 1. The fixing method can be performed by a method such as sticking, fusing, and adhesion. At the time of winding, the outer peripheral tape 20 can be wound spirally by traversing the supply roll of the outer peripheral tape 20 or moving the membrane element 1 in the axial direction or the supply roll side.

  Further, when the outer peripheral tape 20 is wound, it is preferable that the spiral sheets overlap with each other so that there is no gap. Specifically, the overlap of the outer peripheral tape 20 is preferably 5 to 50% of the sheet width. Below this range, a gap is likely to be formed, and when a gap is formed, the adhesion between the separation membrane, the supply-side channel material, and the permeate-side channel material tends to be reduced. If this range is exceeded, the winding time of the outer peripheral tape 20 and the amount of use of the outer peripheral tape 20 will increase, making it difficult to supply inexpensive spiral membrane elements.

  In the present embodiment, as shown in FIG. 6B, when the outer peripheral tape 20 is wound to one axial end, the outer peripheral tape 20 is then wound spirally toward the other axial end. To do. At that time, after the outer peripheral tape 20 is once cut, the winding may be started again from one end portion in the axial direction, but it is preferable that the outer peripheral tape 20 is continuously wound without being cut. When the winding is continuously performed, the winding angle (angle formed between the sheet longitudinal direction and the axial direction) may be gradually changed or may be changed at a time. Further, such a turn portion can be trimmed and removed after the outer peripheral tape 20 is wound.

  In this embodiment, as shown in FIGS. 6C to 6D, when the outer peripheral tape 20 is wound up to the other axial end, the outer peripheral tape 20 is then spiraled toward the vicinity of the axial center. Wind. Also in this case, it is preferable to perform the turn in the same manner as described above. In the present embodiment, the number of winding layers may be further increased.

It is explanatory drawing which shows the structural example of the spiral-type separation membrane element which concerns on one Embodiment of this invention. It is a schematic diagram which shows the cross-sectional shape of the center pipe | tube in the said spiral type separation membrane element. It is a schematic diagram which shows the cross-sectional shape of the other center pipe | tube in the said spiral type separation membrane element. It is a schematic diagram which shows the cross-sectional shape of the other center pipe | tube in the said spiral type separation membrane element. It is a schematic diagram which shows the cross-sectional shape of the other center pipe | tube in the said spiral type separation membrane element. It is a schematic diagram for demonstrating the process of winding an outer periphery tape around the said spiral type separation membrane element.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Spiral type separation membrane element 2 Separation membrane 3 Permeation side flow path material 4 Envelope-shaped membrane 5 Hollow center tube 6 Supply side flow path material 7 Stock solution 8 Permeate 9 Concentrate 10-15 Inner wall surface 20 Outer tape

Claims (3)

Spiral type separation membrane element in which a laminated body in which a separation membrane unit and a permeation channel material are alternately stacked between the separation membranes is wound around a perforated hollow central tube In
The outer shape of the central tube is circular in cross section,
The inner wall surface at the end of the central tube has a circular shape in its cross section, and the other inner wall surface has an elliptical shape in its cross section, and has an elliptical outer shape capable of locking relative rotation. A spiral separation membrane element characterized by having a shape allowing insertion of a shaft. Spiral provided with means for winding a laminated body in which a separation membrane unit and a permeation channel material alternately arranged between separation membranes around a perforated hollow central tube In the manufacturing apparatus of the mold separation membrane element,
A drive shaft for inserting the inside of the central tube to rotate the central tube and winding the laminate around the central tube;
The outer shape is circular in the cross section, the inner wall surface of the end portion has a circular shape in the cross section, and the other inner wall surfaces can lock relative rotation with respect to the central tube having the elliptical shape in the cross section. An apparatus for manufacturing a spiral separation membrane element, comprising a drive shaft having an elliptical outer shape . The apparatus for manufacturing a spiral separation membrane element according to claim 2 , further comprising means for applying tension to an end of the laminated body when the laminated body is wound around the central tube.

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