JP2006136839A - Spiral membrane element - Google Patents

Abstract

There is provided a spiral membrane element in which peeling of a film with an adhesive tape hardly occurs at a bent portion, and a defect due to the peeling does not need to be repaired in a subsequent process.
A separation membrane 1, a supply-side channel material 2, and a permeation-side channel material 3 are provided with a cylindrical wound body wound in a spiral shape around a perforated central tube 5 in a laminated state. In the spiral membrane element provided with a sealing portion for preventing the supply-side fluid and the permeation-side fluid from mixing, the separation membranes 1 that face each other with the supply-side flow path material 2 interposed therebetween are arranged on the inner peripheral side. The end portions are connected by an adhesive tape 7, and the adhesive tape 7 is bonded to the inner surface of the inner peripheral side end portion with the back surface bent into a valley fold.
[Selection] Figure 1

Description

  The present invention relates to a spiral membrane element that separates components suspended and dissolved in a liquid. More specifically, the present invention has a bent portion at an inner peripheral side end so that a separation membrane sandwiches a supply-side channel material. The present invention relates to a spiral membrane element in which an adhesive tape is attached along the inner surface of the bent portion.

  Conventionally, as a fluid separation element used for reverse osmosis filtration, ultrafiltration, microfiltration, etc., for example, a supply-side channel material that guides the supply-side fluid to the surface of the separation membrane, a separation membrane that separates the supply-side fluid, and a separation membrane There is known a spiral membrane element in which a unit made of a permeate-side flow channel material that permeates through and separates a permeate-side fluid separated from a supply-side fluid to a central tube is wound around a perforated central tube.

  As shown in FIGS. 2 (a) to 2 (c), such a spiral membrane element generally has a structure in which the supply-side flow path material 2 is arranged between the separation membrane 1 folded in two and the permeation side. The separation membrane unit U is manufactured by stacking the flow path material 3 and applying adhesives 4 and 6 to the periphery (three sides) of the separation membrane to form a sealing portion that prevents mixing of the supply side fluid and the permeation side fluid. The unit U is manufactured by winding one or more units U around the central tube 5 in a spiral shape and further sealing the periphery of the separation membrane.

  As a result, as shown in FIG. 3, both ends of the separation membrane 1 facing each other through the permeate-side flow path member 3 are sealed by both-end sealing portions 11, and a plurality of both-end sealing portions 11 arranged in a spiral shape. Between them, the supply-side flow path material 2 is interposed. Moreover, the outer peripheral side edge part of the separation membrane 1 which opposes through the permeation | transmission side flow path material 3 is sealed by the outer peripheral side sealing part 12 along the axial direction. This example is a case where there are a plurality of membrane leaves (sealed envelope-like membranes), but there are cases where there is a single membrane leaf.

  And as shown in FIG. 2, said separation membrane 1 has the bending part 1a in an inner peripheral side edge part so that the supply side flow-path material 2 may be pinched | interposed, and the adhesive tape 7 along the inner surface of the bending part 1a May be attached. The reason why the adhesive tape 7 is attached is that a defect occurs in the separation membrane 1 due to bending. Therefore, the adhesive tape 7 is sealed so that liquid does not permeate from the defect, and the supply-side flow path member 2 is This is because the bent portion 1a is protected by the adhesive tape 7 so that the film surface is not damaged by the edge of the tape when inserted.

  However, if the separation membrane with the adhesive tape attached is bent, the adhesive tape on the inside may bend due to the difference in the radius of curvature between the membrane and the adhesive tape. And when an adhesive tape bends in M shape, a film | membrane (for example, polysulfone layer) will also be peeled together from the nonwoven fabric which is a base material. Therefore, a defect due to peeling of the M-shaped tape occurs in the bent portion (see FIG. 4). Conventionally, in order to repair this defect, a step of applying a resin to the tip of the fold portion (around the central tube) in the finishing step after forming the element has been required.

  As described above, when manufacturing the spiral membrane element, as a technique for sticking the adhesive tape to the bent portion of the separation membrane, an invention in which the tip of the fold portion is thermocompression bonded (for example, see Patent Document 1), An invention (for example, see Patent Document 2) in which a streak or a perforation is formed in a bent portion is known.

However, these inventions have the same or more elastic modulus than conventional ones because, for the purpose of preventing swelling of the bent portion of the separation membrane, heating is performed when the adhesive tape is bent, or the adhesive tape is pre-stitched. It is considered that a material having a high thickness is used. For this reason, when using the adhesive tape of patent documents 1-2, it is thought that an adhesive tape bends in M shape like the past, and the film | membrane peels in that case.
JP 10-137558 A JP-A-10-137559

  Accordingly, an object of the present invention is to provide a spiral-type membrane element in which peeling of a film with an adhesive tape hardly occurs at a bent portion, and a defect due to the peeling does not need to be repaired in a subsequent process.

  The above object can be achieved by the present invention as described below.

  That is, the spiral membrane element of the present invention is a cylindrical wound body in which a separation membrane, a supply-side channel material, and a permeate-side channel material are spirally wound around a perforated central tube. And the separation membrane facing each other across the supply-side flow path member is arranged on each inner periphery thereof in the spiral membrane element provided with a sealing portion for preventing mixing of the supply-side fluid and the permeation-side fluid. The side end portions are connected by an adhesive tape, and the adhesive tape is bonded to the inner surface of the inner peripheral side end portion with the back surface bent into a valley fold.

  According to the present invention, the adhesive tape is attached to the inner surface of the inner peripheral side end portion of the separated separation membrane while the adhesive tape is bent, and both are connected, and thus the adhesive tape is attached to the continuous separation membrane. In comparison, it is possible to provide a spiral membrane element in which the film is hardly peeled off by the adhesive tape at the bent portion, and the defect due to the peeling does not need to be repaired in a subsequent process.

  In the above, it is preferable that the inner peripheral side end portion of the separation membrane is formed by cutting one separation membrane bent at a substantially center at the bent portion and connected by the adhesive tape. With such a structure, only by adding a separation membrane cutting step to the conventional manufacturing method, it is difficult for the membrane to be peeled off by the adhesive tape at the bent portion, and there is no need to repair defects due to the peeling in a subsequent step. A mold membrane element can be manufactured.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a process diagram showing an example of a method for producing a spiral membrane element of the present invention.

  The spiral membrane element of the present invention does not have a bent portion at the inner peripheral side end of the separation membrane 1 and connects the inner peripheral side end of the separated separation membrane 1 while bending the adhesive tape 7. Only the point is different from the conventional one, and any other structure of the conventional spiral membrane element described above can be applied to other structures. Therefore, the spiral membrane element of the present invention generally has the structure shown in FIG. 3 as in the conventional element.

  As shown in FIGS. 1 and 3, the spiral membrane element of the present invention includes a separation membrane 1, a supply-side channel material 2, and a permeate-side channel material 3 around a perforated central tube 5 in a laminated state. And a cylindrical wound body R wound in a spiral shape, and a sealing portion for preventing mixing of the supply side fluid and the permeation side fluid. The sealing portion includes a both-end sealing portion 11 and an outer peripheral side sealing portion 12.

  As shown in FIG. 3, both ends of the separation membrane 1 facing each other through the permeate-side flow path member 3 are sealed by both-end sealing portions 11, and between a plurality of both-end sealing portions 11 arranged in a spiral shape. Is provided with a supply-side channel material 2. Moreover, the outer peripheral side edge part of the separation membrane 1 which opposes through the permeation | transmission side flow path material 3 is sealed by the outer peripheral side sealing part 12 along the axial direction.

  The cylindrical wound body R is formed by spirally winding the separation membrane 1, the supply-side channel material 2, and the permeate-side channel material 3 around the perforated center tube 5. It can be manufactured by a step of forming the rotating body R and a step of forming a sealing portion for preventing mixing of the supply side fluid and the permeation side fluid. In the present embodiment, as shown in FIG. 1, an example is shown in which one separation membrane bent at substantially the center is cut at the bent portion, and then the adhesive tape 7 is attached and connected. 1A is a plan view of the separation membrane unit U, FIG. 1B is a front view of the separation membrane unit U, and FIG. 1C is a view before the separation membrane unit U is stacked and wound. It is a front view which shows a state.

  First, as shown in FIGS. 1A to 1B, the supply side flow path member 3 and the permeate side flow path member 3 are stacked while the separation membrane 1 is folded in half, and the supply fluid and A separation membrane unit U is prepared in which adhesives 4 and 6 for forming sealing portions 11 and 12 for preventing permeation of the permeated fluid are applied to both end portions in the axial direction of the permeation-side flow path member 3 and the winding end portion. . At this time, the separation membrane 1 is bent at the inner peripheral side end so as to sandwich the supply-side flow path material 2. After the separation membrane 1 is cut at this bent portion, the back surface is folded and the adhesive tape 7 is folded. It is bent and attached to the inner surface of the inner peripheral side end of the separation membrane 1.

  By this, the inner peripheral side edge part of the separation membrane 1 is connected, and the adhesive tape 7 has a structure in which the back surface is bent into a valley fold and adhered to the inner surface of the inner peripheral side edge part. Thus, since only the adhesive tape 7 has the bent portion 7a, it is possible to prevent the occurrence of defects due to peeling of the M-shaped tape, which has been a problem in the past.

  The pressure-sensitive adhesive tape 7 may have a structure having a pressure-sensitive adhesive layer on at least one side of the base material, and the same one as in the past can be used. Examples of the pressure sensitive adhesive include acrylic pressure sensitive adhesive, rubber pressure sensitive adhesive, and silicone pressure sensitive adhesive. Moreover, as a base material, polyester-type films, such as a polyethylene terephthalate and a polyethylene naphthalate, a polypropylene film, etc. are preferable.

  As the separation membrane 1, a reverse osmosis membrane, an ultrafiltration membrane, a microfiltration membrane, or the like can be used. However, the present invention is a composite ultrafiltration membrane, a reverse osmosis membrane, or a skin layer using a nonwoven fabric as a support layer. This is particularly effective in the case of a reverse osmosis membrane having a (dense layer) and a porous layer (support layer).

  According to the present invention, it is possible to effectively prevent the problem of peeling due to M-shaped deformation of the adhesive tape, which is likely to occur when the tensile modulus of the separation membrane 1 is 1000 to 2000 MPa and the total thickness is 80 to 200 μm. be able to.

  A net-like material, a knitted material, or the like can be used for the supply-side channel material 2. A net-like or knitted material or the like can be used for the permeate-side channel material 3. The perforated center tube 5 only needs to have an opening around the tube, and any conventional tube can be used.

  As the adhesives 4 and 6, any conventionally known adhesives such as urethane adhesives and epoxy adhesives can be used. Moreover, the sealing parts 11 and 12 can also be formed using a hot-melt adhesive, a heat-fusing adhesive tape, a heat-fusing sheet, or the like.

  Next, as shown in FIG. 1 (c), a plurality of the separation membrane units U are stacked and wound around the perforated center tube 5 in a spiral shape, and then the adhesives 4, 6 and the like are heated. The cylindrical wound body R is obtained by curing or the like. At that time, the periphery of the central tube 5 may be sealed at the same time. The cylindrical wound body R is trimmed at both ends as necessary in order to adjust the axial length.

  The number when the separation membrane unit U is stacked is determined according to the required permeation flow rate and may be one or more layers, but the upper limit is about 100 layers in consideration of operability. The larger the number of separation membrane units U stacked, the fewer the number of turns of each separation membrane unit U.

  The spiral membrane element of the present invention is usually constrained by an exterior material and does not expand in diameter, but the exterior material is formed by winding one or more sheets around the surface of the cylindrical wound body R. Can do. As the exterior material, polyester, polypropylene, polyethylene, polyvinyl chloride, glass fiber cloth, or the like can be used.

  The spiral membrane element of the present invention may be further provided with a perforated end member for preventing deformation (telescope or the like), a sealing material, a reinforcing material, and the like as necessary.

[Other Embodiments]
(1) In the above-described embodiment, an example is shown in which one separation membrane bent at substantially the center is cut at the bent portion, and then an adhesive tape is attached and connected. You may connect both by sticking an adhesive tape to each inner peripheral side edge part using two separate separation membranes. In that case, the outer peripheral side sealing part 12 may be made unnecessary by using the separation membrane 1 in which the inner peripheral side end is continuous.

  (2) In the above-described embodiment, as shown in FIG. 1, the permeation-side channel material 3 is overlapped on the separation membrane 1 folded in half so as to sandwich the supply-side channel material 2, and the adhesive 4 In the present invention, it is also possible to apply the adhesives 4 and 6 on the separation membrane 1 that is folded in two on the permeate-side channel material 3.

  (3) In the above-described embodiment, as shown in FIG. 1, an example in which a spiral membrane element including a plurality of membrane leaves is manufactured using a plurality of separation membrane units U has been described. A spiral membrane element having one membrane leaf may be manufactured using a set of separation membrane units U.

Process drawing which shows an example of the manufacturing method of the spiral type membrane element of this invention Process diagram showing a conventional spiral membrane element manufacturing method Partially broken perspective view showing an example of a conventional spiral membrane element Electron micrograph of the bent part of the separation membrane in a conventional spiral membrane element

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Separation membrane 2 Supply side channel material 3 Permeation side channel material 5 Center tube 7 Adhesive tape R Cylindrical winding body U Separation membrane unit

Claims (2)

A separation membrane, a supply-side flow path material, and a permeate-side flow path material are provided with a cylindrical wound body spirally wound around a perforated central tube in a laminated state, and a supply-side fluid and a permeation-side fluid In the spiral membrane element provided with a sealing portion for preventing the mixing of
The separation membranes facing each other across the supply-side channel material are connected to each inner peripheral end by an adhesive tape, and the adhesive tape is bent at the back in a valley fold to A spiral membrane element characterized in that it is adhered to the inner surface.   2. The spiral membrane element according to claim 1, wherein an inner peripheral side end of the separation membrane is formed by cutting a single separation membrane bent at a substantially central portion at the bent portion and connected by the adhesive tape.

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