JP4482932B2 - Flat membrane element and support plate - Google Patents

Description

  The present invention relates to a flat membrane element and a support plate, and more particularly to a flat membrane element and a support plate that are immersed in water to be treated such as waste water and perform solid-liquid separation by filtering the water to be treated.

  Conventionally, a flat membrane element that is immersed in water to be treated such as waste water and performs solid-liquid separation by filtering the water to be treated, as disclosed in Patent Documents 1 and 2, is the periphery of a filterable membrane sheet Are formed on a support plate having a rectangular plate shape.

  When filtration is performed with this flat membrane element, suction is performed from a discharge port provided in the support plate. The water to be treated passes through the membrane sheet by the suction force from the discharge port, is collected as filtered water, and is discharged outside the system.

Further, the flat membrane element is periodically cleaned with chemicals in order to maintain its filtering ability. As a main chemical cleaning method, a method of injecting a chemical solution into the discharge port after stopping suction to the discharge port is employed. As a result, the membrane surface of the flat membrane element is cleaned by the chemical that has permeated from the back surface.
JP-A-6-178920 JP-A-7-132214

  However, since the conventional flat membrane element has a vertically long rectangular shape, the pressure at the time of suction or injection is biased over the entire membrane surface of the flat membrane element, so that filtration and chemical cleaning can be performed efficiently. There was a problem that I could not.

  As a countermeasure, in the flat membrane element of Patent Documents 1 and 2, the depression and groove are provided on the support plate to facilitate the formation of the flow path of the filtered water and the chemical solution, so that the flat membrane element can be uniformly filtered and treated on the entire surface. Although cleaning is possible, the communication between the discharge port and the outer surface of the support plate is performed through one hole. Therefore, the pressure at the time of suction or injection of the entire flat membrane element is concentrated in the one hole. Therefore, at the time of suction filtration, the suction force concentrates on the membrane sheet closer to the hole and the degree of contamination of the membrane surface becomes higher. There was a problem that it was greatly reduced.

  Moreover, in the flat membrane element of patent document 1 and 2, since the dent and the groove | channel were formed on the support plate, there existed a problem that the intensity | strength of a support plate will fall by the dent and groove | channel.

  As a countermeasure, it is also considered to reinforce the strength by increasing the thickness of the support plate. However, since the weight of the support plate itself increases, the work efficiency decreases when handling the flat membrane element, and the support plate A new drawback arises in that the material costs increase.

  The present invention has been made in view of such circumstances, and a flat membrane element and a support plate that can uniformly perform filtration and chemical cleaning on the entire surface of the membrane sheet without using particularly complicated devices and members. The purpose is to provide.

In order to achieve the above object, the invention according to claim 1 is a flat membrane formed by bonding the periphery of a membrane sheet to at least one surface of the front and back of a support plate, and filtering the water to be treated by the membrane sheet. In the element, the support plate is formed on a surface to which the membrane sheet of the support plate is joined, and a plurality of water collecting grooves for collecting filtrate water filtered by the membrane sheet;
A combined flow path where the filtrate collected by the plurality of water collecting grooves joins, and a communication hole formed at one end of each of the plurality of water collecting grooves and communicating the water collecting grooves and the combined flow path; A discharge port that is provided in the combined flow path and discharges the filtered water; and a full-surface filtration mechanism for uniformly filtering the entire surface of the membrane sheet, and the distance from the discharge port as the full-surface filtration mechanism The cross-sectional area of the water collecting groove is increased as the distance increases .
In order to achieve the above object, the invention according to claim 2 is a flat membrane formed by joining the periphery of a membrane sheet to at least one surface of the front and back surfaces of a support plate, and filtering water to be treated with the membrane sheet. In the element, the support plate is formed on a surface to which the membrane sheet of the support plate is joined, and a plurality of water collecting grooves for collecting filtrate water filtered by the membrane sheet;
A combined flow path where the filtrate collected by the plurality of water collecting grooves joins, and a communication hole formed at one end of each of the plurality of water collecting grooves and communicating the water collecting grooves and the combined flow path; A discharge port that is provided in the combined flow path and discharges the filtered water; and a full-surface filtration mechanism for uniformly filtering the entire surface of the membrane sheet, and the distance from the discharge port as the full-surface filtration mechanism The distance between the water collecting grooves is narrowed as the distance becomes longer.
In order to achieve the above object, the invention according to claim 3 is a flat membrane formed by joining the periphery of a membrane sheet to at least one surface of the support plate and filtering the water to be treated with the membrane sheet. In the element, the support plate is formed on a surface of the support plate to which the membrane sheet is bonded, and includes a plurality of water collecting grooves for collecting filtered water filtered by the membrane sheet, and the plurality of collecting plates. A combined flow path where the filtrate collected in the water groove joins, a communication hole formed at one end of each of the plurality of water collection grooves, and communicating the water collection groove and the combined flow path; and An exhaust port for discharging the filtered water, and a full-surface filtration mechanism for evenly filtering the entire surface of the membrane sheet, and the communication as the distance from the discharge port increases as the full-surface filtration mechanism. Characterized by increasing the hole diameter

According to the first to third aspects of the invention, when a pressure difference is generated in the flat membrane element immersed in the water to be treated by sucking the discharge port, the membrane surface of the flat membrane element is treated. Water is solid-liquid separated by the membrane sheet and taken as filtered water between the membrane sheet and the support plate. The filtered water taken in between the membrane sheet and the support plate is collected by a plurality of water collecting grooves formed on the support plate. The filtered water collected in each of the water collecting grooves is collected into the combined flow path through the communication hole, and is discharged out of the system from the discharge port. Thus, since filtered water is collected from a plurality of locations on the support plate to the combined flow path, it is possible to perform filtration without unevenness throughout the flat membrane element.
Further, in the rectangular flat membrane element, the pressure applied to the water collecting groove tends to decrease as the distance from the discharge port increases. Therefore, in the first aspect of the present invention, the cross-sectional area of the water collecting groove is increased as the distance from the discharge port is increased as the entire surface filtering mechanism, and the pressure loss of the filtered water flowing through the water collecting groove is increased in all the water collecting grooves. It was made uniform at the position. Thereby, since the pressure loss of the water collecting groove generated at a distance from the discharge port can be made uniform, it is possible to uniformly perform filtration on the entire surface of the flat membrane element. In addition, even when chemical cleaning is performed, since the drug injected from the discharge port can be uniformly supplied to the entire surface, efficient drug cleaning can be performed.
Moreover, in the rectangular flat membrane element, the pressure applied on the surface of the support plate tends to decrease as the distance from the discharge port increases. Therefore, in the invention described in claim 2, the distance between the water collecting grooves becomes narrower as the distance from the discharge port becomes longer as a full-surface filtration mechanism. Thereby, since the density of the water collecting grooves is larger in the support portion far from the discharge port than in the close support portion, it is possible to uniformly filter the entire flat membrane element. In addition, even when chemical cleaning is performed, since the drug injected from the discharge port can be uniformly supplied to the entire surface, efficient drug cleaning can be performed.
Further, in the rectangular flat membrane element, the pressure applied to each communication hole tends to decrease as the distance from the discharge port increases. Therefore, in the invention according to the third aspect, the hole diameter of each communication hole is increased as the distance from the discharge port is increased as the entire surface filtration mechanism. Thereby, since the pressure loss of each communicating hole produced at the distance from the discharge port can be reduced, suction filtration can be performed uniformly over the entire flat membrane element. In addition, even when chemical cleaning is performed, since the drug injected from the discharge port can be uniformly supplied to the entire surface, efficient drug cleaning can be performed.

According to a fourth aspect of the present invention, in order to achieve the object, in the flat membrane element according to any one of the first to third aspects, the combined flow path is based on a total volume of the water collecting groove. It has a volume of 2 times or more.

According to the invention described in claim 4 , since the loss of pressure applied from the discharge port to the water collection port can be adjusted by the combined flow path, the filtered water filtered by the membrane sheet is uniformly distributed over the entire surface of the support. Can collect water.

According to a fifth aspect of the present invention, in order to achieve the above object, in the flat membrane element according to any one of the first to fourth aspects, the water collecting groove is formed of the support plate formed in a rectangular shape. It is formed by making a cut in parallel to the short direction, and the combined channel is formed in the longitudinal direction of the support.

According to the fifth aspect of the present invention, it is possible to shorten the length of the water collecting groove by forming the water collecting groove in the short direction instead of the longitudinal direction of the support body formed in a rectangular shape. Since the distance can be shortened, it is easy to equalize the pressure loss of the filtered water flowing through the water collecting groove. Thereby, it can filter uniformly on the whole surface of a membrane sheet. Moreover, when handling a flat membrane element, the intensity | strength with respect to the stress concerning a support plate can be improved.

The invention according to claim 6 is characterized in that, in order to achieve the object, in the flat membrane element according to any one of claims 1 to 5 , at least a part of the combined flow path has transparency. To do.

If filtration is continuously performed using a flat membrane element, a leak may occur during the filtration for some reason, and solid-liquid separation may not be performed normally. For this reason, the flat membrane element being filtered is regularly checked for leaks. According to the invention which concerns on Claim 6 , since at least one part of the combined flow path has transparency, the generated leak can be confirmed from a combined flow path. Thereby, since it becomes unnecessary to disassemble and confirm the flat membrane element, the time required for the inspection work can be greatly shortened.

In order to achieve the object, the invention according to claim 7 is the flat membrane element according to any one of claims 1 to 6 , wherein the membrane sheet is bonded to both front and back surfaces of the support plate, and the support is supported. The water collecting grooves formed on the surface of the plate and the water collecting grooves formed on the back surface of the support plate are arranged so as not to overlap each other.

According to the seventh aspect of the present invention, the water collecting grooves are formed on both the front and back surfaces of the support plate. At this time, if the water collecting grooves are arranged at the same position on the front and back of the support plate, the strength of the support plate is lowered. Although the strength can be maintained by increasing the thickness of the support plate, it is difficult to handle due to an increase in material cost and weight. On the other hand, although the strength reduction can be suppressed by reducing the depth of the water collecting groove, there arises a problem that the efficiency of collecting the filtered water in the water collecting groove is lowered. Therefore, by arranging so that the position of the water collecting groove provided on the front surface of the support plate and the position of the water collecting groove provided on the back surface do not overlap, the filtered water can be efficiently flowed through the water collecting groove. In addition, the strength reduction can be suppressed without increasing the thickness of the support plate.

In order to achieve the above object, according to an eighth aspect of the present invention, in the flat membrane element according to the seventh aspect , the depth of the water collecting groove is not less than 0.05 times the thickness of the support plate. In some cases, the distance between the center of the water collecting groove on the front side and the center of the water collecting groove on the back surface of the support plate is at least twice the width of the water collecting groove. And

By the invention described in claim 8 lever, with a possible further suppress strength reduction of the support plate, it is possible to improve the injection efficiency of the water collecting efficiency and chemical filtration water in the water collecting groove.

The invention according to claim 9, in order to achieve the object, a support plate for supporting the membrane sheet for filtration of the water to be treated, formed on a surface for supporting the membrane sheet of the support plate, wherein A plurality of water collecting grooves for collecting filtered water filtered by the membrane sheet, a combined flow path for collecting the filtered water collected by the plurality of water collecting grooves, and one end of the plurality of water collecting grooves Formed in each of the above, a communication hole for communicating the water collecting groove and the combined flow path, a discharge port provided in the combined flow path for discharging the filtered water, and for uniformly filtering the entire surface of the membrane sheet A full-surface filtration mechanism, and as the full-surface filtration mechanism, the cross-sectional area of the water collecting groove is increased as the distance from the discharge port is increased.
In order to achieve the above object, the invention according to claim 10 is a support plate that supports a membrane sheet for filtering water to be treated, and is formed on a surface of the support plate that supports the membrane sheet, A plurality of water collecting grooves for collecting filtered water filtered by the membrane sheet, a combined flow path for collecting the filtered water collected by the plurality of water collecting grooves, and one end of the plurality of water collecting grooves Formed in each of the above, a communication hole for communicating the water collecting groove and the combined flow path, a discharge port provided in the combined flow path for discharging the filtered water, and for uniformly filtering the entire surface of the membrane sheet And a full-surface filtration mechanism, wherein the distance between the water collecting grooves is reduced as the distance from the discharge port is increased.
In order to achieve the object, the invention according to claim 11 is a support plate that supports a membrane sheet that filters water to be treated, and is formed on a surface of the support plate that supports the membrane sheet, A plurality of water collecting grooves for collecting filtered water filtered by the membrane sheet, a combined flow path for collecting the filtered water collected by the plurality of water collecting grooves, and one end of the plurality of water collecting grooves Formed in each of the above, a communication hole for communicating the water collecting groove and the combined flow path, a discharge port provided in the combined flow path for discharging the filtered water, and for uniformly filtering the entire surface of the membrane sheet And a full-surface filtration mechanism, wherein the diameter of the communication hole is increased as the distance from the discharge port is increased.

According to invention of Claims 9-11 , the filtered water filtered with the membrane sheet is collected by the several water collecting groove formed in the support plate. The filtered water collected in each of the water collecting grooves is collected into the combined flow path through the communication hole, and is discharged out of the system from the discharge port. As described above, the filtered water is collected from a plurality of locations on the support plate to the combined flow path, so that the entire membrane sheet can be filtered evenly.
Further, in the rectangular flat membrane element, the pressure applied to the water collecting groove tends to decrease as the distance from the discharge port increases. Therefore, in the invention described in claim 9, as the entire surface filtration mechanism, the cross-sectional area of the water collecting groove is increased as the distance from the discharge port increases, and the pressure loss of the filtered water flowing through the water collecting groove is increased in all the water collecting grooves. It was made uniform at the position. Thereby, since the pressure loss of the water collecting groove generated at a distance from the discharge port can be made uniform, it is possible to uniformly perform filtration on the entire surface of the flat membrane element. In addition, even when chemical cleaning is performed, since the drug injected from the discharge port can be uniformly supplied to the entire surface, efficient drug cleaning can be performed.
Moreover, in the rectangular flat membrane element, the pressure applied on the surface of the support plate tends to decrease as the distance from the discharge port increases. Therefore, in the invention described in claim 10, as the entire surface filtration mechanism, the distance between the water collecting grooves becomes narrower as the distance from the discharge port becomes longer. Thereby, since the density of the water collecting grooves is larger in the support portion far from the discharge port than in the close support portion, it is possible to uniformly filter the entire flat membrane element. In addition, even when chemical cleaning is performed, since the drug injected from the discharge port can be uniformly supplied to the entire surface, efficient drug cleaning can be performed.
Further, in the rectangular flat membrane element, the pressure applied to each communication hole tends to decrease as the distance from the discharge port increases. Therefore, in the invention described in claim 11, the hole diameter of each communication hole is increased as the distance from the discharge port is increased as the entire surface filtration mechanism. Thereby, since the pressure loss of each communicating hole produced at the distance from the discharge port can be reduced, suction filtration can be performed uniformly over the entire flat membrane element. In addition, even when chemical cleaning is performed, since the drug injected from the discharge port can be uniformly supplied to the entire surface, efficient drug cleaning can be performed.

In order to achieve the above object, the support plate according to any one of claims 9 to 11 , wherein the water collecting grooves are formed on both front and back surfaces of the support. The water collecting groove formed on the surface of the support plate and the water collecting groove formed on the back surface of the support plate are arranged so as not to overlap each other.

  According to the twelfth aspect of the present invention, the water collecting grooves are formed on both the front and back surfaces of the support plate, the water collecting grooves formed on the surface of the support plate, and the water collecting grooves formed on the back surface of the support plate; Are arranged so as not to overlap each other. Thereby, while being able to flow filtered water efficiently, the fall of intensity | strength can be suppressed even if it does not thicken a support plate.

  As described above, according to the flat membrane element and the support plate of the present invention, it is possible to perform filtration and chemical cleaning uniformly and efficiently on the entire surface of the flat membrane element without reducing the strength of the support plate. Thereby, the cost and labor required for the flat membrane element can be reduced.

  Hereinafter, preferred embodiments of a flat membrane element and a support plate according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a perspective view showing a configuration of a flat membrane element 10 according to an embodiment of the present invention, and shows a state where a part thereof is cut away.

  As shown in the figure, the flat membrane element 10 is mainly composed of a membrane sheet 12 and a support plate 14.

  The membrane sheet 12 is made of a material having water permeability, and a flat membrane capable of solid-liquid separation of water to be treated is used.

  The support plate 14 is a plate material having a vertically long rectangular shape, and mainly includes a film surface portion 14a to which the film sheet 12 is bonded, side surface portions 14b and 14b, a cavity portion 16, and a transparent portion 18. . The film surface portion 14 a, the side surface portions 14 b and 14 b, and the cavity portion 16 are integrated, and the support plate 14 is formed by joining the transparent portion 18. As the material for the film surface portion 14a, the side surface portions 14b and 14b, and the cavity portion 16, it is preferable to employ a thermoplastic resin having laser absorptivity. For example, an ABS resin containing carbon black is used. On the other hand, the material of the transparent portion 18 is preferably a resin having transparency and laser transparency, and for example, an ABS resin or the like is used. In addition, it is preferable that the transparent part 18 is welded by irradiating a laser from the outside of the transparent part 18. Thereby, it can fix firmly and stably firmly.

  The membrane surface portion 14 a is joined to the periphery of the membrane sheet 12 at the joint portion 13, thereby forming a membrane surface on the flat membrane element 10 in a state where the membrane sheet 12 is stably supported on the support plate 14.

  The side surface parts 14b and 14b form both side surfaces of the film surface part 14a, and the thickness is set larger than that of the film surface part 14a. Thereby, when several flat membrane element 10,10 ... is arrange | positioned in parallel, the space | interval of the film surface parts of the adjacent flat membrane element 10 can be stably arrange | positioned by a predetermined space | interval. In addition, it is preferable that the thickness of the side surface parts 14b and 14b is 7 mm if the thickness of the film surface part 14a is 5 mm.

  One side surface portion 14b is provided with a hollow portion 16 indicated by a broken line that is hollowed from the side surface to a part of the film surface portion 14a. By joining the transparent portion 18 to the hollow portion 16, a support plate is provided. A joint channel is formed at 14.

  At the upper end of the transparent portion 18, the discharge port 20 is installed in communication with the hollow portion 16, and is connected to a suction pump (not shown) installed outside. The discharge ports 20 are alternately arranged in the vertical direction so that when the plurality of flat membrane elements 10, 10... Are arranged in parallel, the discharge ports 20, 20 between the adjacent flat membrane elements 10, 10 do not overlap. It is preferable.

  A plurality of water collecting grooves 22, 22... Are formed in parallel in the lateral direction (short direction of the supporting plate 14) on the membrane surface portions 14 a, 14 a on both sides of the support plate 14. .. Are provided with communication holes 24, 24. In addition, the combined flow path comprised from the cavity part 16 and the transparent part 18 is set so that it may have a volume 2 times or more with respect to the sum total of the volume of each water collecting groove 22,22 ....

  FIG. 2 is a perspective view showing the positional relationship between the water collecting grooves 22 and 22 and the communication holes 24 and 24 arranged on the front and back surfaces of the membrane surface portion 14a of the support plate 14, and a part of the support plate 14 is cut off. Indicates the state.

  As shown in the figure, the water collecting grooves 22 and 22 on the front side and the back side are arranged at positions that do not overlap each other, and the communication holes 24 and 24 on the front side and the back side are arranged at the same position. Accordingly, the water collecting grooves 22 and 22 on the front side and the back side are connected to positions that do not overlap with the communication holes 24 and 24. The communication holes 24, 24... Are formed so as to penetrate from the membrane surface portion 14a to the cavity portion 16. The interval between the front and back sides of each water collecting groove 22, 22 is such that the depth of the water collecting grooves 22, 22 is 0.05 times or more the thickness of the membrane surface portion 14a. It is preferable that the distance connecting the center and the center of the water collecting groove 22 on the back surface is twice or more the width of each water collecting groove 22, 22. That is, the water collecting grooves 22 and 22 are arranged according to the formula shown in Equation 1. A is the thickness of the membrane surface 14a, B is the depth of the water collecting groove 22, C is the width of the water collecting groove 22, and D is the center of the water collecting groove 22 on the front side and the water collecting groove 22 on the back surface. The distance connecting with the center of.

(Equation 1) B ≧ A / 20, D ≧ 2C
FIG. 3 is a schematic diagram showing an outline of the positional relationship and width of the water collecting grooves 22, 22... Provided on the front and back surfaces of the membrane surface portion 14a of the support plate 14, and FIG. FIG. 3B shows the case where the width of the water collecting grooves 22, 22... Is adjusted, and FIG. 3C shows the distance between the water collecting grooves 22, 22. And the case where the width is adjusted is shown.

  As shown in FIGS. 3 (B) and 3 (C), each of the water collecting grooves 22, 22... Formed on the support plate 14 is enlarged in width according to the distance from the discharge port 20. The width is set in the range of 2 mm or more and less than 4 mm. Further, as shown in FIGS. 3A and 3C, the intervals between the water collecting grooves 22, 22... Are narrowed, and the communication holes 24, 24. Arranged at the same interval. Further, each of the communication holes 24, 24... Has a hole diameter set in a range of 4 mm or more and less than 8 mm, and is formed by expanding the hole diameter according to the distance from the discharge port 20. Thereby, the whole surface filtration mechanism for filtering to-be-processed water in the membrane sheet 12 whole surface of the flat membrane element 10 is formed.

  Next, the operation of the flat membrane element 10 according to the embodiment of the present invention configured as described above will be described.

  When the flat membrane element 10 is immersed in the water to be treated, and a suction pump (not shown) provided outside is driven to perform suction from the discharge port 20 of the flat membrane element 10, The treated water permeates through the membrane sheet 12 and is separated into solid and liquid, and is taken in between the membrane sheet 12 and the support plate 14 as filtered water. The filtered water taken in flows through the water collecting grooves 22, 22... By the suction force from the discharge port 20, flows down to the communication holes 24, 24. The In this way, the filtered water is preferentially collected along a plurality of water collecting grooves 22, 22... Juxtaposed on the surface of the support plate 14, and each communication hole 24 provided at one end of the water collecting grooves 22, 22. , 24..., 24 can be filtered over the entire surface of the flat membrane element 10. In addition, the combined flow path is set to have a capacity that is at least twice as large as the volume of each of the water collecting grooves 22, 22. Since this is done, the suction force can be dispersed throughout the flat membrane element 10.

  By the way, the flat membrane element 10 is provided with only one discharge port 20 on the upper side surface of the combined flow path for convenience. Therefore, the pressure loss tends to increase at a position far from the discharge port 20.

  Therefore, in the flat membrane element 10 of the present invention, the cross-sectional area of the water collecting grooves 22, 22..., That is, the width and depth of the grooves is 2 mm or more and less than 4 mm depending on the distance from the discharge port 20. It was adjusted. That is, when the width is less than 2 mm in the water collecting grooves 22, 22..., The amount of filtered water flowing through the water collecting grooves 22, 22. It tends to be adsorbed by the water grooves 22, 22. Therefore, by adjusting the width of each water collecting groove 22, 22 ... within the range of 2 mm or more and less than 4 mm according to the distance from the discharge port 20, pressure loss due to the positional relationship can be made uniform, The filtered water taken in on the surface of the support plate 14 can be evenly collected into the combined flow path.

  Moreover, in the flat membrane element 10 of this invention, the space | interval of the water collection grooves 22, 22 ... and the communicating holes 24, 24 ... was set narrowly according to the distance from the discharge port 20 as a whole surface filtration mechanism. As a result, a large number of water collecting grooves 22, 22... And communication holes 24, 24... Can be arranged below the support plate 14 having a large pressure loss, and the pressure loss due to the positional relationship can be made uniform. The filtered water taken in on the surface can be evenly collected into the combined flow path.

  Further, in the flat membrane element 10 of the present invention, the hole diameter of the communication holes 24, 24... Thereby, in the combined flow path, the suction force to the water collecting grooves 22, 22... Easily concentrated in the vicinity of the discharge port 20 can be evenly distributed downward.

  Therefore, by providing the flat membrane element 10 with these full-surface filtration mechanisms, it is possible to efficiently filter the entire surface of the membrane sheet 12, and therefore it is possible to prevent the life of the flat membrane element 10 from being deteriorated due to a bias in filtration. . In addition, when performing regular chemical cleaning, the injected chemical can be uniformly permeated into the entire surface of the membrane sheet 12. Therefore, the entire membrane sheet 12 can be efficiently cleaned by the injected medicine, and the life of the flat membrane element 10 can be extended.

  By the way, the support plate 14 needs to have a structure that can withstand the impact and water pressure when being put into the water to be treated, withdrawn, and immersed. However, if the water collecting grooves 22, 22... Are provided on both surfaces of the support plate 14, the strength of the support plate 14 may be reduced. Although it is considered to increase the thickness of the support plate 14 in order to maintain the strength while maintaining the water collection efficiency, there are problems in terms of workability such as ease of handling and the cost required for the support plate.

  Therefore, in the flat membrane element 10 of the present invention, the positions of the water collecting grooves 22, 22... Formed on the front and back surfaces of the membrane surface portion 14a are arranged at intervals shown by the equation (1).

  FIG. 4 is a graph showing the strength of the support plate 14 with respect to the ratio between the width C of the water collecting groove 22 and the distance D connecting the centers of the water collecting grooves 22 and 22 on the front and back surfaces.

  In the graph of FIG. 4, when the distance D connecting the centers of the water collecting grooves 22 and 22 is more than twice the width C of the water collecting grooves 22, the increase in strength in the support plate 14 is stagnant. It was. Therefore, the thickness of the support plate 14 can be minimized while maintaining the strength of the support plate 14 by setting each of the water collecting grooves 22, 22. In addition, since the water collecting grooves 22, 22... Are provided in the lateral direction, the impact and water pressure applied to the flat membrane element 10 can be relieved, so that the strength against the thickness of the support plate 14 can be improved. it can. Therefore, by adopting the flat membrane element 10 of the present invention, it is possible to improve workability in the immersion filtration process and reduce the material cost while having strength against impact and water pressure.

  Moreover, when performing immersion filtration using the flat membrane element 10, so-called leakage occurs in which solid matter such as sludge existing in the water to be treated enters without being subjected to membrane treatment for some reason. If a leak occurs, solid-liquid separation with respect to the water to be treated cannot be performed with certainty. Therefore, it is necessary to replace the flat membrane element 10 in which the leak has occurred. In the flat membrane element 10 according to the present invention, since a transparent material is used for the combined flow path, the flat portion in which a leak has occurred can be obtained simply by visually observing the transparent portions 18, 18. The membrane element 10 can be confirmed immediately. As a result, it is possible to greatly reduce the labor required for checking the leak and to detect the occurrence of the leak at an early stage.

  In addition, since the transparent portion 18 can transmit laser, and the side surface portion 14b to be welded is formed of a resin having laser absorbability, it is irradiated by irradiating the laser from the outside of the transparent portion 18. The resin at the interface of the side surface portion 14b is dissolved, and the transparent portion 18 can be welded and fixed by the dissolved heat. As a result, fixing with high hermeticity and strength can be reliably performed in a short time, and since no adhesive is used, peeling of the transparent portion 18 due to deterioration of the adhesive can be prevented.

  In the flat membrane element 10 described above, the number, shape, material, and the like of each member and device are not particularly limited.

  In the flat membrane element 10, the filtration process has been described by suction filtration using a suction pump, but is not particularly limited. You may perform siphon type suction filtration and filtration using the pressurization by gravity.

  In the support plate 14, the joint portion is formed by welding the transparent portion 18 to the cavity portion 16 formed in the one side surface portion 14 b, but is not particularly limited. As long as it has high hermeticity and strength and communicates with each of the communication holes 24, 24..., A tubular or tubular member may be installed on the support plate 14 as a combined flow path.

  Moreover, although the transparent material was used only for the transparent portion 18, it is not particularly limited. If all the members constituting the support plate 14 are made transparent, the inside of the flat membrane element 10 can be confirmed at a glance, so that the inspection of the leak in the flat membrane element 10 can be reliably performed in a shorter time. .

  In the present embodiment, the case where the present invention is applied to the flat membrane element in which the membrane sheet 12 is bonded to both the front and back surfaces of the support plate 14 has been described as an example. However, the application of the present invention is limited to this. It is not a thing. The present invention can be similarly applied to a flat membrane element in which a membrane sheet is bonded to at least one surface of the support plate. In the case of a flat membrane element in which a membrane sheet is bonded to one of the front and back surfaces of the support plate, the water collecting groove is formed on the surface of the support plate on the side where the membrane sheet is bonded. That is, when the membrane sheet is bonded only to the surface of the support plate, a water collecting groove is formed only on the surface of the support, and when the membrane sheet is bonded only to the back surface of the support plate, A water collecting groove is formed only on the back surface.

The perspective view which showed the structure of the flat membrane element which is embodiment of this invention The schematic diagram which showed the positional relationship of the water collection groove | channel and communication hole which were arrange | positioned at the support plate in the flat membrane element of this invention The schematic diagram which showed the positional relationship of each water collecting groove in the flat membrane element of this invention The graph which showed the relationship with the intensity | strength of a support plate with respect to the ratio of the width | variety of the water collecting groove in the flat membrane element of this invention, and the distance which tied the center of the water collecting groove of the surface and the back surface

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Flat membrane element, 12 ... Membrane sheet, 13 ... Joint part, 14 ... Support plate, 14a ... Membrane surface part, 14b ... Side surface part, 16 ... Cavity part, 18 ... Transparent part, 20 ... Discharge port, 22 ... Water collection Groove, 24 ... communicating hole

Claims (12)

In the flat membrane element that is formed by joining the periphery of the membrane sheet to at least one surface of the support plate, and filters the water to be treated with the membrane sheet,
The support plate is
A plurality of water collecting grooves formed on the surface of the support plate to which the membrane sheet is bonded and collecting filtered water filtered by the membrane sheet;
A combined flow path where the filtrate collected by the plurality of water collecting grooves joins;
A communication hole formed at one end of each of the plurality of water collecting grooves, and communicating the water collecting groove and the combined flow path;
A discharge port provided in the combined flow path for discharging the filtered water;
A full surface filtration mechanism for evenly filtering the entire surface of the membrane sheet,
The flat membrane element characterized in that the cross-sectional area of the water collecting groove is increased as the distance from the discharge port becomes longer as the full surface filtration mechanism. In the flat membrane element that is formed by joining the periphery of the membrane sheet to at least one surface of the support plate, and filters the water to be treated with the membrane sheet,
The support plate is
A plurality of water collecting grooves formed on the surface of the support plate to which the membrane sheet is bonded and collecting filtered water filtered by the membrane sheet;
A combined flow path where the filtrate collected by the plurality of water collecting grooves joins;
A communication hole formed at one end of each of the plurality of water collecting grooves, and communicating the water collecting groove and the combined flow path;
A discharge port provided in the combined flow path for discharging the filtered water;
A full surface filtration mechanism for evenly filtering the entire surface of the membrane sheet,
The flat membrane element characterized in that the distance between the water collecting grooves becomes narrower as the distance from the discharge port becomes longer as the full surface filtration mechanism. In the flat membrane element that is formed by joining the periphery of the membrane sheet to at least one surface of the support plate, and filters the water to be treated with the membrane sheet,
The support plate is
A plurality of water collecting grooves formed on the surface of the support plate to which the membrane sheet is bonded and collecting filtered water filtered by the membrane sheet;
A combined flow path where the filtrate collected by the plurality of water collecting grooves joins;
A communication hole formed at one end of each of the plurality of water collecting grooves, and communicating the water collecting groove and the combined flow path;
A discharge port provided in the combined flow path for discharging the filtered water;
A full surface filtration mechanism for evenly filtering the entire surface of the membrane sheet,
The flat membrane element characterized in that the hole diameter of the communication hole is increased as the distance from the discharge port becomes longer as the entire surface filtration mechanism.   The flat membrane element according to any one of claims 1 to 3, wherein the combined flow path has a volume that is twice or more the total volume of the water collecting grooves.   The water collecting groove is formed by cutting in parallel to a short direction of the support plate formed in a rectangular shape, and the combined channel is formed in a longitudinal direction of the support. Item 5. The flat membrane element according to any one of Items 1 to 4.   The flat membrane element according to any one of claims 1 to 5, wherein at least a part of the joint channel has transparency.   The membrane sheets are bonded to both the front and back surfaces of the support plate, and the water collecting grooves formed on the surface of the support plate and the water collecting grooves formed on the back surface of the support plate are arranged so as not to overlap each other. The flat membrane element according to any one of claims 1 to 6, wherein   When the depth of the water collecting groove is not less than 0.05 times the thickness of the support plate, the distance connecting the center of the water collecting groove on the front side and the center of the water collecting groove on the back surface of the support plate in the shortest distance The flat membrane element according to claim 7, wherein is more than twice the width of the water collecting groove. A support plate for supporting a membrane sheet for filtering water to be treated,
A plurality of water collecting grooves formed on a surface of the support plate for supporting the membrane sheet and collecting filtered water filtered by the membrane sheet;
A combined flow path where the filtrate collected by the plurality of water collecting grooves joins;
A communication hole formed at one end of each of the plurality of water collecting grooves, and communicating the water collecting groove and the combined flow path;
A discharge port provided in the combined flow path for discharging the filtered water;
A full surface filtration mechanism for evenly filtering the entire surface of the membrane sheet,
The support plate according to claim 1, wherein the entire surface filtration mechanism includes a larger cross-sectional area of the water collecting groove as a distance from the discharge port is longer. A support plate for supporting a membrane sheet for filtering water to be treated,
A plurality of water collecting grooves formed on a surface of the support plate for supporting the membrane sheet and collecting filtered water filtered by the membrane sheet;
A combined flow path where the filtrate collected by the plurality of water collecting grooves joins;
A communication hole formed at one end of each of the plurality of water collecting grooves, and communicating the water collecting groove and the combined flow path;
A discharge port provided in the combined flow path for discharging the filtered water;
A full surface filtration mechanism for evenly filtering the entire surface of the membrane sheet,
The support plate according to claim 1, wherein the entire surface filtering mechanism includes a narrower interval between the water collecting grooves as the distance from the discharge port increases. A support plate for supporting a membrane sheet for filtering water to be treated,
A plurality of water collecting grooves formed on a surface of the support plate for supporting the membrane sheet and collecting filtered water filtered by the membrane sheet;
A combined flow path where the filtrate collected by the plurality of water collecting grooves joins;
A communication hole formed at one end of each of the plurality of water collecting grooves, and communicating the water collecting groove and the combined flow path;
A discharge port provided in the combined flow path for discharging the filtered water;
A full surface filtration mechanism for evenly filtering the entire surface of the membrane sheet,
The support plate according to claim 1, wherein the entire surface filtering mechanism includes a larger diameter of the communication hole as a distance from the discharge port becomes longer.   The water collecting grooves are formed on both front and back surfaces of the support, and are arranged so that the water collecting grooves formed on the surface of the support plate and the water collecting grooves formed on the back surface of the support plate do not overlap each other. The support plate according to any one of claims 9 to 11, wherein the support plate is formed.

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