JP6460856B2 - Membrane element manufacturing method - Google Patents

Description

The present invention relates to a method for producing a membrane element used for membrane separation activated sludge treatment.

  Conventionally, in membrane separation activated sludge treatment, a membrane separation apparatus is used in which a plurality of membrane elements are arranged at predetermined intervals in a case and an air diffuser is provided below these membrane elements.

  As shown in FIG. 9, the membrane element 101 has a filter plate 102 and separation membranes 103 provided on both sides of the filter plate 102. The separation membrane 103 is joined to the filter plate 102 along the peripheral edge by, for example, heat welding. A joint 104 (welded part) between the separation membrane 103 and the filter plate 102 is formed in a square frame shape formed of a straight line. An area surrounded by the joint 104 is an effective filtration area 105. In this effective filtration area 105, the liquid to be treated passes through the separation membrane 103 to obtain a permeate.

  According to this, during the filtration operation, by performing aeration with the aeration device, an upward flow 106 of the gas-liquid mixed phase flowing from the bottom to the top between the membrane elements 101 is generated, and the upward flow 106 causes the filter plate to flow. 102 vibrates. Due to this vibration, the separation membrane 103 is shaken, and stress is repeatedly generated in the joint portion 104, the joint portion 104 is deteriorated with time, and the separation film 103 is peeled off or broken at the location of the joint portion 104. Further, when the separation membrane 103 peels or breaks at the joint 104, the joint 104 is formed in a straight line, and therefore, the separation or break is enlarged along the length direction of the joint 104. There is.

  As measures against this problem, as shown in FIG. 10, it is conceivable to form a plurality of linear joint portions 104 and 110 inside and outside, or to form a mesh-like auxiliary joint portion 111 outside the joint portion 110. . According to this, by providing the joints 104 and 110 in a multiple manner, even if a part of the joints 104 and 110 is peeled off or broken, it is possible to ensure the sealing performance of the joints 104 and 110 as a whole. It does not reduce the stress itself generated at the joints 104 and 110. The membrane element 101 in which such a plurality of joints 104 and 110 and auxiliary joints 111 are formed is described in, for example, Patent Document 1 below.

Japanese Patent No. 4996979

  In the conventional type shown in FIG. 10, the stress itself generated in the joints 104 and 110 cannot be reduced, and the joints required to form the plurality of joints 104 and 110 and the auxiliary joints 111 are not possible. Since the area 112 (space) is enlarged, the effective filtration area 105 may be reduced.

An object of this invention is to provide the manufacturing method of the membrane element which can prevent that a separation membrane peels or fractures | ruptures in the location of a junction part.

In order to achieve the above object, the first invention is a membrane element in which a separation membrane made of an organic membrane is provided on the surface of a synthetic resin filter plate, and the separation membrane is joined to the filter plate along the peripheral edge. A manufacturing method of
By pressing the heating plate against the filter plate with the separation membrane sandwiched between the heating plate with the unevenness formed on the pressing surface and the filter plate, the peripheral edge of the separation membrane and the filter plate are joined. The junction part which has the unevenness | corrugation in the thickness direction of a membrane element is formed .

According to this, by pressing the heating plate against the filter plate with the separation membrane sandwiched between the heated heating plate and the filter plate, the peripheral edge of the separation membrane and the filter plate are welded and joined. As a result, a joint having irregularities in the thickness direction is formed.
Since the joint has irregularities in the thickness direction of the membrane element along its length direction, the joint is bent (or curved) in an irregular shape in the thickness direction, and compared to a linear joint without irregularities. The length of the part becomes longer. Thereby, the stress generated in the joint is dispersed, whereby the stress per unit length of the joint is reduced, and the separation film can be prevented from peeling or breaking at the joint.

In the manufacturing method of the membrane element in the second invention, the filter plate has a protrusion protruding in the thickness direction on the peripheral edge of the surface,
By pressing the heating plate against the projection of the filter plate, the peripheral edge of the separation membrane and the filter plate are joined.

  According to this, with the separation membrane sandwiched between the heated heating plate and the filter plate, by pressing the heating plate against the projection of the filter plate, the peripheral edge of the separation membrane and the projection of the filter plate Are welded together. At this time, since the protrusions of the filter plate melt in an uneven shape corresponding to the unevenness of the heating plate, the heat of the heating plate is concentrated and transmitted to the protrusions of the filter plate, and the protrusions of the filter plate are efficiently transferred. It can be softened or melted, and a joint having unevenness in the thickness direction is formed.

In the manufacturing method of the membrane element in the third invention, the unevenness of the heating plate is formed by repeating the same pattern.

  As described above, according to the present invention, the joint portion is bent (or curved) in the uneven direction in the thickness direction along the length direction thereof. Length increases. Thereby, the stress generated in the joint is dispersed, whereby the stress per unit length of the joint is reduced, and the separation film can be prevented from peeling or breaking at the joint.

1 is a partially cutaway perspective view of a membrane separation apparatus including a membrane element according to a first embodiment of the present invention. FIG. 2 is a front view of the membrane element. It is a partially expanded perspective view showing the manufacturing method of the membrane element, wherein (a) shows a state before the separation membrane is welded to the filter plate with a heating plate, and (b) shows the separation membrane welded to the filter plate. Shown later. FIG. 2 is a partially enlarged side view of the membrane element. It is an enlarged view which shows the shape of the uneven | corrugated | grooved part of the junction part of the separation membrane and filter plate of a membrane element similarly. It is an enlarged view which shows the shape of the uneven | corrugated | grooved part of the junction part of the separation membrane of a membrane element and the filter plate in the 2nd Embodiment of this invention. It is an enlarged view which shows the shape of the uneven | corrugated | grooved part of the junction part of the separation membrane of a membrane element and the filter plate in the 3rd Embodiment of this invention. It is an enlarged view of the junction part of the separation membrane of the membrane element in the 4th Embodiment of this invention, and a filter plate, (a) shows the figure which looked at the junction part from the front, (b) is (a). FIG. It is a front view of the conventional membrane element. It is a partially expanded front view of another conventional membrane element.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
In the first embodiment, as shown in FIG. 1, reference numeral 1 denotes a membrane separation device used for membrane separation activated sludge treatment, and this membrane separation device 1 is installed by being immersed in a treatment tank (not shown). ing. The membrane separation device 1 includes a case 3, a plurality of plate-like membrane elements 4 accommodated in the case 3, and an air diffuser 5 installed below the membrane element 4.

The case 3 is open at both upper and lower ends, and is divided into an upper film case 7 and a lower air diffusion case 8. The diffuser 5 is installed in the diffuser case 8.
As shown in FIGS. 2 to 5, the membrane element 4 includes a square plate-shaped filter plate 9 made of a thermoplastic synthetic resin (for example, ABS resin), and separation membranes 10 provided on both surfaces of the filter plate 9. And are arranged at predetermined intervals with the film surfaces facing each other. The separation membrane 10 is an organic membrane, and is joined to the filter plate 9 by thermal welding along the peripheral edge. As a result, a rectangular frame-shaped joint 12 is formed at the peripheral edge of the separation membrane 10. An area surrounded by the joint 12 is an effective filtration area 13.

  A permeate passage (not shown) through which the permeate 14 flows is formed between the filter plate 9 and the separation membrane 10 and inside the filter plate 9, and a permeate outlet 15 communicating with the permeate passage is connected to the filter plate 9. It is provided at the upper end of the plate 9. As shown in FIG. 1, the permeate outlet 15 is connected to the permeate outlet 15, and the permeate outlet 16 is provided with a suction pump (not shown) for sucking the permeate 14. Yes.

  The joint portion 12 has a plurality of concave and convex portions 20 and 21 in the thickness direction T of the membrane element 4 along the length direction thereof. The concavo-convex portions 20 and 21 are formed by repeating the same corrugated pattern. 3 to 5, the concave and convex portions 20 and 21 are shown exaggerated from the actual one in order to make it easier to grasp the shape. Actually, as shown in FIG. The height H from the bottom part to the top part of the convex part 21 is smaller than the pitch P of the uneven parts 20, 21, and the height H is set in a range of 0.3 to 1 mm and the pitch P is set to 1 to 3 mm.

  FIG. 3A shows the filter plate 9 before the separation membrane 10 is joined. The filter plate 9 has protrusions 23 protruding in the thickness direction T on the peripheral portions of both surfaces. Yes. Both protrusions 23 are each formed in a square frame shape, and the width W of the protrusion 23 is set to 3 mm as an example.

  As shown in FIG. 3A, the heating plate 24 is a square frame-shaped member used when the membrane element 4 is manufactured, and the thickness direction T of the membrane element 4 is formed on the pressing surface 24 a against the filter plate 9. Concave and convex portions 25 and 26 corresponding to. The concave and convex portions 25 and 26 of the heating plate 24 are formed by repeating the same corrugated pattern in the same manner as the concave and convex portions 20 and 21 of the joining portion 12.

Below, the manufacturing method of the said membrane element 4 is demonstrated.
As shown in FIG. 3 (a), the separation membrane 10 is sandwiched between the heating plate 24 and the filter plate 9, and in this state, the heating plate 24 is pressed against the protrusion 23 of the filter plate 9, The peripheral edge of the separation membrane 10 and the protrusion 23 of the filter plate 9 are welded and joined. At this time, since the protrusions 23 of the filter plate 9 melt in an uneven shape corresponding to the uneven portions 25 and 26 of the heating plate 24, the thickness direction along the length direction is shown in FIG. The joint portion 12 having the uneven portions 20 and 21 at T is formed. Thereafter, the heating plate 24 is detached from the filter plate 9.

After the separation membrane 10 is bonded to the front and back surfaces of the filter plate 9 in this way, the front and back surfaces of the filter plate 9 are reversed, and the separation membrane 10 is bonded to the opposite surface of the filter plate 9 in the same manner.
In the membrane element 4 manufactured as described above, since the joint portion 12 has the uneven portions 20 and 21 in the thickness direction T along the length direction thereof, the joint portion 12 is bent in an uneven shape in the thickness direction T. (Or curved), and the length of the joint 12 becomes longer than that of a conventional straight joint without an uneven portion. Thereby, the stress generated in the joint 12 is dispersed, so that the stress per unit length of the joint 12 is reduced, and the separation film 10 is prevented from peeling or breaking at the joint 12. Can do.

  In the said 1st Embodiment, although the junction part 12 which has the uneven | corrugated parts 20 and 21 is formed by heat welding, even if the junction part 12 which has the uneven | corrugated parts 20 and 21 is formed by ultrasonic welding, Alternatively, the joining portions 12 having the concavo-convex portions 20 and 21 may be formed by forming the concavo-convex portions 20 and 21 on the filter plate 9 in advance and joining the separation membrane 10 to the filter plate 9 by laser welding or an adhesive. May be formed.

(Other embodiments)
In the first embodiment, the concavo-convex portions 20 and 21 of the joint portion 12 are formed in an arc shape as shown in FIG. 5, but in the second embodiment, the concavo-convex portions 20 and 21 are formed as shown in FIG. 21 may be a triangular wave shape, and in the third embodiment, the concavo-convex portions 20 and 21 may be a square wave shape as shown in FIG. Alternatively, as shown in FIG. 8, instead of the corrugated shape as in the first to third embodiments, as shown in FIG. 8, the recess 20 is circular when viewed from the thickness direction T of the membrane element 4 (or (A polygon such as a triangle or a quadrangle), and a convex portion 21 may be formed between the concave portions 20 adjacent to each other.

4 Membrane Element 9 Filter Plate 10 Separation Membrane 12 Joints 20 and 21 Concave and Convex 23 Protrusions 24 Heating Plate 24a Pressing Surfaces 25 and 26 Concave and Convex Part T Thickness Direction

Claims (3)

A separation membrane made of an organic membrane is provided on the surface of a synthetic resin filter plate, and the separation membrane is a method for producing a membrane element joined to the filter plate along the peripheral edge,
By pressing the heating plate against the filter plate with the separation membrane sandwiched between the heating plate with the unevenness formed on the pressing surface and the filter plate, the peripheral edge of the separation membrane and the filter plate are joined. A method for producing a membrane element, comprising forming a joint having irregularities in the thickness direction of the membrane element. The filter plate has a protrusion protruding in the thickness direction on the peripheral edge of the surface,
The method for manufacturing a membrane element according to claim 1, wherein the peripheral edge of the separation membrane and the filter plate are joined by pressing the heating plate against the protrusion of the filter plate. The method for manufacturing a membrane element according to claim 1 or 2, wherein the unevenness of the heating plate is formed by repeating the same pattern.

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