JP2005169273A - Filtering device having pleat filter united with housing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the defect that a liquid to be filtered is likely to be wasted since the amount of the remaining liquid increases at the finishing stage of filtration due to a large volume of an occupied flow passage in conventional filtering devices housing pleat filters in containers, especially in a filtering device for filtering a small amount of the liquid to be filtered. <P>SOLUTION: A filtering device is provided with a cylindrical part having a cylindrical inside space with both ends opened , an annular pleat filter (a filer membrane is bent in a pleat shape and formed in a cylinder shape) inserted into the inside space in contact with the inner wall of the above cylindrical part and with the top and bottom end surfaces sealed with tight liquid, a perforated core supporting the inner peripheral surface of the pleat filter, a lower cover body and an upper cover body connected respectively to both of the ends of the cylindrical part with the tight liquid, a supply passage of the liquid to be filtered communicating with the inner surface of a housing, a supply opening of the liquid to be filtered connected to the supply passage, a discharge passage of the filtrate communicating with the inside passage of the perforated core, and a discharge opening of the filtrate connected to the discharge passage. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a technique for filtering a liquid, and more particularly to a filtration apparatus using a pleated filter integrated with a housing, which is suitable for filtering a small amount of liquid and efficiently filters a liquid to be filtered.

In the filtration of liquids, particularly in the case of expensive chemical solutions such as in the semiconductor industry, a small amount of filtration such as about 1 liter is often performed, and the need to increase the recovery rate of the remaining liquid after filtration is also increasing.
In particular, in filtration operations that require high accuracy, the size of captured particles is gradually becoming a finer area, and there is a demand for more advanced technology for this. A trapping performance of 0.02 μm has been required.
When the primary purpose is to minimize the remaining amount of liquid on the primary side in a conventional filtration system, a disk filter (a disk-shaped porous membrane filter supported on a porous support disk) is cylindrical. However, in the conventional structure, the filtration area of the disk filter relative to the dimensions of the container is relatively small, so the processing time tends to be longer due to the small filtration area. . That is, the filtration area of the disk-shaped filter can only obtain a filtration area proportional to the square of the outer diameter.
As a countermeasure, by using a laminated filter (stack filter) in which two or more disk filters are superposed, a filtration area that is several times as many as the filtration area of one disk filter can be obtained, and the processing time is shortened. In this case, a liquid passage is required between the inner surface of the container for housing the laminated filter and the outer diameter of the disk filter, and between the laminated disk filters. By adding the side channel volume, the volume required for one disk filter increases according to the number of layers. Therefore, in the case of a small amount of filtration, there is a problem that the remaining amount of liquid remaining in the container at the end of the filtration operation is large.

On the other hand, in a filter device in which a so-called pleated filter, in which a filtration membrane is folded in a pleated shape and stored in a container, is stored in a container, the filtration area is much larger than that of a disk filter for a container of the same size. However, there is an advantage that the processing time is shortened, and it is possible to meet a wide range of filtration operation requirements, but there is a structural disadvantage with respect to the remaining amount of the processing liquid.
That is, in the case of considering processing of a desired amount of processing liquid within a specified time in the pleated filter, the filtration area can be increased without increasing the flow volume so much, and the pressure loss can be minimized. However, even in this type of structural design, an inner porous cylinder (core) and an outer porous cylinder having a large number of openings through which liquid flows are usually provided between the pleated filter and the housing to support the inner and outer peripheral surfaces of the pleated filter. (Sleeve) is required, and an internal passage must be formed in the core, and a space for a liquid passage must be formed between the sleeve and the cylindrical container (housing) (for example, Patent Document 1). These passages become the stagnation of the remaining liquid because the liquid cannot be filtered under pressure at the end of the filtration process, resulting in the disadvantage of forming a residual liquid space as it is.
In a small amount of filtration operation, the processing time becomes longer when trying to minimize the filtration accuracy and the residual amount of processing liquid inside the container, and when the filtration accuracy and processing time are shortened, the residual amount inside the container increases and the efficiency of the filtering operation increases. It will be reduced.

JP-A-5-111622

  Therefore, the problem to be solved by the present invention is a simple filter device capable of minimizing the residual amount inside the container even though it is a pleated filter that can improve the filtration accuracy and shorten the processing time. There is to provide in structure.

The present invention solves the above-described problem by inserting a cylindrical portion having a cylindrical inner space open at both ends, and the upper and lower end surfaces of the inner space are sealed in a liquid-tight manner while being in direct contact with the inner wall of the cylindrical portion. Annular pleated filter (filter membrane is folded into a pleat and formed into a cylindrical shape), a porous core that supports the inner peripheral surface of the pleated filter, and both ends of the cylindrical portion are liquid-tightly joined. A lower lid body and an upper lid body that form a liquid-tight housing together with the cylindrical portion, a liquid distribution passage to be filtered that communicates between the pleats of the pleated filter from the lower end portion of the cylindrical portion, and the distribution passage. Filtration comprising a filtrate supply path, a filtrate supply port connected to the supply path, a filtrate discharge path leading to the internal passage of the porous core, and a filtrate discharge port connected to the discharge path Solve by equipment That.
According to this configuration, neither the outer porous cylinder (sleeve) nor the outside to-be-filtered liquid supply passage as in Patent Document 1 exists between the pleated filter and the inner wall surface of the cylindrical portion constituting the outer peripheral wall of the housing. Since the space occupied by the liquid to be filtered is reduced by that amount, the remaining amount of filtration is reduced. In the present invention, the liquid to be filtered is directly supplied between the pleats from the outside of the pleat filter via the supply passage. According to the experiment, the filtration time for a constant filtration amount is not limited by the conventional pleated filter without any particular increase in flow resistance. It has been found that it is no different from a filtration device.

  According to one aspect of the present invention, the filtrate supply port is provided in the lower lid, and the filtrate discharge port is provided in the upper lid. In this form, the structure of the cylindrical portion and the upper and lower lids is simplified, the resin molding die is simplified, and the manufacture of the filtration device is inexpensive and easy.

  According to another aspect of the invention, the filtrate supply port is provided in the cylindrical portion, and the filtrate discharge port is provided in the upper lid. Although this form makes the production of the resin mold somewhat complicated, it is advantageous in some cases because the liquid to be filtered can be supplied in the horizontal direction.

  According to another embodiment of the present invention, the lower end side of the inner peripheral surface of the cylindrical portion has a divergent tapered surface toward the lower open end, and the distribution path is formed between the tapered surface and the cylindrical pleat. It is defined by the outer peripheral surface of the filter. According to this configuration, the liquid is easily distributed among all the pleats of the pleated filter and the filtration efficiency is increased.

  According to still another embodiment of the present invention, the lower lid is a cup-shaped member having an annular portion having an inner diameter larger than the inner diameter of the cylindrical portion, and the outer periphery of the lower end of the cylindrical portion is the annular portion. And a through-hole is formed in the thin-walled portion, and the distribution path is constituted by the gap and the through-hole. According to this embodiment, the liquid is easily supplied from the gap through the penetrating groove, to the entire outer peripheral surface of the pleated filter, and thereby easily distributed between the pleats. On the other hand, the lower end of the thin portion can support the lower end of the pleated filter.

  In another preferred embodiment of the present invention, the bottom edge of the pleated filter, the bottom surface of the porous core, and the bottom surface of the cylindrical portion are sealed with a single disc-shaped plastic sheet. According to this, the bottom surface of the pleated filter can be easily sealed, and a supply passage for the liquid to be processed is formed between the lower cap of the pleated filter and the plastic sheet, so that the liquid can be uniformly distributed to the outer periphery of the pleated filter. It becomes possible. Similarly, the sealing of the upper edge portion of the pleated filter is facilitated by interposing a plastic sheet.

  In another preferred embodiment of the present invention, the volume occupied by the internal passage and the porous portion of the porous core is limited to 50% or less of the total volume of the porous core. Thereby, the residual liquid amount can be further reduced. In this case, in order to improve the flow of the filtrate from the inner peripheral surface of the pleated filter, the porous passage desirably has a flow passage cross-sectional area that is wide on the upstream side and narrow on the internal passage side.

  In another preferred embodiment of the present invention, the upper end side of the inner peripheral surface of the cylindrical portion has a tapered surface that is divergent toward the upper open end, and the gas collecting path is formed by the tapered surface and the outer peripheral surface of the cylindrical pleated filter. And a gas vent passage and a gas vent port communicating therewith are provided in the cylindrical portion or the upper lid. Preferably, further, another gas vent passage connected from the filtrate supply passage to the gas vent passage is provided in the cylindrical portion. In this form, it is possible to separate and remove dissolved gas and bubbles in the liquid to be treated.

Since the present invention has a small size and a small capacity as described above, the sleeve is eliminated and the flow path is narrowed as an important measure. For this reason, a structure in which the liquid to be filtered spreads evenly over each pleat of the pleat is adopted.
In the first aspect of the present invention,
(1) Structure of the cylindrical portion The cylindrical portion is shaped so that both ends are open. The cylindrical portion has an inner diameter that directly holds the pleated filter formed in a cylindrical shape. In order to provide a distribution path for performing substantially uniform distribution and supply of the liquid to be filtered, (a) the lower end portion of the cylindrical portion has a smaller diameter than the inner diameter of the peripheral wall of the lower lid, and a large through hole is provided. By having the thin-walled portion, an annular filtered liquid distribution path is formed with the inner peripheral surface of the lower lid, and the liquid to be filtered can be easily supplied from the lower end of the pleated filter between the pleats. Or (b) the inner peripheral surface of the lower end of the cylindrical portion has a tapered surface that expands toward the open end, thereby providing a liquid distribution path to be filtered between the outer peripheral surface of the cylindrical pleated filter. It is desirable to form.
Further, as a means for discharging the gas dissolved in the liquid to be filtered, it is desirable that the inner peripheral upper end side of the cylindrical portion has a tapered surface that expands toward the open end. Thereby, a gas collection path is formed between the tapered surface and the outer peripheral surface of the cylindrical pleated filter, and can be led to the gas vent hole through the gas vent passage.
(2) Structure of the lower lid In the case of (a) in (1) above, the liquid to be filtered is smoothly supplied and distributed between the pleated filter pleats around the thin wall portion through the liquid passage of the thin wall portion. In order to provide a supply flow path, the lower lid is configured as a cup-shaped member having an inner diameter larger in diameter than the thin-walled portion and an outer shape that can be welded to the lower end portion of the cylindrical portion. The The upper edge of the cup-shaped member is welded to the lower edge of the cylindrical portion. In the case of (b) in (1) above, it is only necessary that the filtrate supply path communicates with the distribution path between the tapered surface of the cylindrical portion and the pleated filter.
(3) Core structure It is necessary to have a columnar structure with a reduced internal capacity as much as possible, instead of a conventional simple porous cylinder. For this reason, the volume of the internal passage and the porous part is 50% or less of the volume of the porous core. It is desirable to suppress it.
(4) Auxiliary fusion film In order to reduce the number of parts, it is necessary to weld the upper and lower ends of the core simultaneously when the upper and lower ends of the pleated filter are sealed by welding. As a means for this, the disc-shaped plastic film is sealed in a state where it is applied to at least the lower end surface of the core (or an annular plastic film when used for sealing at the upper end surface) and the lower end surface (preferably further the upper end surface) of the pleated filter. It is desirable to wear.

In the second aspect of the present invention,
(1) Structure of cylindrical portion As in the first embodiment, the shape of the cylindrical portion is made open at both ends. The cylindrical portion has an inner diameter that directly holds the pleated filter formed in a cylindrical shape. The upper and lower lids are formed in a plate shape, and the cylindrical portion is welded to these upper and lower lids. In order to allow the liquid to be filtered to be easily supplied between the pleats from the lower end portion of the pleated filter, the inner peripheral lower end side of the cylindrical portion is a tapered surface that expands toward the lower end open end, thereby forming a tapered surface. A distribution path for the liquid to be filtered is formed between the outer peripheral surface of the cylindrical pleated filter. The distribution path is connected to the filtrate supply port through the filtrate supply path provided in the cylindrical portion. By providing the supply path in a tangential direction with respect to the outer peripheral surface of the cylindrical pleated filter, the liquid to be filtered enters the outer peripheral surface of the pleated filter from the supply path from the tangential direction, and the tapered surface and the outer peripheral surface of the pleated filter are Almost evenly distributed among all pleats along the distribution path between them.
(2) Structure of lower lid body The lower lid body may be a simple plate-like one and has an outer shape that can be welded to the lower end portion of the cylindrical portion.
(3) Core structure The configuration is the same as that in the first embodiment.
(4) Welding auxiliary film In addition, when sealing the upper and lower ends of a filter by welding, it is necessary to also weld the upper and lower ends of a core simultaneously. As an auxiliary means, a disc-shaped plastic film that assists adhesion may be applied to the lower end surface of the core and the lower end surface of the pleated filter, and the annular plastic film may be sealed in contact with the upper end surface of the core and the upper end surface of the pleated filter. desirable. In some cases, these films may be further extended between the cylindrical portion and the lid.

  Preferred embodiments of the filtration device of the present invention will be described below with reference to the drawings. In addition, each material of the cylindrical part which is the structural member constituting the container part of the present invention, the upper and lower lids, the porous core, and the pleated filter which is the functional member is used in consideration of corrosion resistance, chemical resistance, heat resistance, etc. However, since the structure and the manufacturing method of the pleated filter are well known from Patent Document 1, etc., they will not be described in detail here. See literature. In order to facilitate understanding, the same or similar members are denoted by the same reference numerals in each embodiment, and different portions will be described separately.

1A and 1B show a filtering device according to a first embodiment of the present invention, in which FIG. 1A is a front elevation sectional view, FIG. 1B is a plan view, and FIG. 1C is a bottom view.
The filtration device 1 according to this embodiment is inserted into the inner space in contact with an inner wall surface 39 (FIG. 2) of the cylindrical portion 3 having both ends open and provided with a cylindrical inner space. A cylindrical pleated filter 5 whose edge is liquid-tightly sealed, a porous core 7 having a large number of openings for supporting the inner peripheral surface of the pleated filter 5, and upper and lower ends of the cylindrical portion 3 respectively. The lower lid body 9 and the upper lid body 11 are joined in a liquid-tight manner, and the cylindrical portion 3 and the upper and lower lid bodies 9 and 11 together form a liquid-tight housing or a liquid-tight container.

The lower lid body 9 is provided with a filtrate supply port 15, and the supply port 15 is provided at the lower end of the cylindrical portion 3 through the filtrate supply path 13 extending along the inner surface of the lower lid body 9. It communicates with an annular distribution path 21 formed between the outer peripheral surface of the thin portion 33 and the inner peripheral surface of the annular portion 19 of the lower lid 9. The distribution path 21 communicates between the pleats of the pleat filter 5 through a plurality of openings 35 arranged in the circumferential direction. The supply path 13 is formed by separating the lower end surfaces of the porous core 7 and the pleat filter 5 from the inner bottom surface of the lower lid body 9, thereby allowing the liquid to be filtered (supply liquid) to flow around the pleated filter 5. Can be uniformly distributed. In this embodiment, the lower end surfaces of the porous core 7 and the pleated filter 5 are hermetically closed with a non-porous disc-shaped plastic film 6. The plastic film is made from a member that helps adhere the members to be welded. Further, in order to reduce the volume of the supply passage 13 of the lower lid 9, the bottom of the inner surface of the annular portion 19 and the lower end surfaces of the porous core 7 and the pleated filter 5 are hermetically closed by a non-porous disc-shaped plastic film 6. It is also possible to make a close contact with the finished surface. That is, in this case, a plurality of grooves may be provided at the bottom of the inner surface of the annular portion 19 in the direction of the distribution path 21 from the supply port 15 provided at the bottom. The lower lid 9 may further be provided with a residual liquid discharge port 17 that leads to the supply path 13 in some cases.
The lower lid body 9 is formed in a cup shape, and the annular portion 19 is formed thinner than the cylindrical portion 3, thereby surrounding the outer periphery of the thin portion 33 at the lower end of the pleated filter 5, 21 is formed. The thin portion 33 having the opening 35 provided at the lower end of the cylindrical portion 3 may be a simple cylindrical body, but more preferably, it is configured as a tapered portion as shown in FIG. it can. The inner peripheral surface of the thin portion 33 constitutes a part of the inner peripheral surface of the cylindrical portion 3 and supports the lower end portion of the pleated filter 5. Further, the thin portion 33 is welded integrally with the disk-shaped plastic film, so that the supply of the liquid to be filtered is uniformly distributed to the outer periphery of the pleated filter through the opening 35.

On the other hand, the upper lid body 11 is provided with a filtrate discharge passage 25 that communicates with the internal passage 23 of the porous core 7 and a filtrate discharge port 27 that is connected to the discharge passage 25.
Preferably, an annular vent passage 29 is formed at the joint between the upper lid 11 and the cylindrical portion 3, and this vent passage is connected to the vent port 31. As will be described later, the vent passage 29 communicates with the filtrate supply passage 13 and the peripheral portion of the pleated filter 5, and discharges the gas dissolved in the filtrate or present as bubbles.

FIG. 2 shows a cylindrical portion for constituting a part of the container of the filtration device according to the first embodiment, wherein (a) is a front elevational sectional view and (b) is a bottom view.
As shown in FIGS. 1A and 2, the inner surface 39 of the cylindrical portion 3 serves as a support surface for directly supporting the pleated filter 5. The cylindrical portion 3 includes a thin portion 33 at the lower end, and the thin portion 33 has three (generally plural) elongated openings 35 extending in the circumferential direction. It is desirable that the angle α at which the opening is stretched is as large as possible (for example, 100 °) to reduce the flow resistance as much as possible. Further, as described above, the annular distribution path 21 is formed by the thin portion 33.
The cylindrical portion 3 is provided with a vent passage 41 that vertically penetrates the wall portion, the lower end is connected to the filtrate supply passage 13 or the annular distribution passage 21, and the upper end is connected to the lower portion of the annular gas vent passage 29. ing. Further, in order to improve the gas vent, the upper end side of the inner peripheral surface of the cylindrical portion 3 has a taper surface 8 that widens toward the upper end and expands at an angle β, so that the gap between the outer peripheral surface of the pleat filter 5 and the taper surface 8 is increased. A gas collection path is formed in the area. A part of the gas vent passage 29 is connected to the gas collection path by a lateral passage 45 and draws out the gas accumulated on the outer periphery of the pleated filter 5.
As shown in FIG. 1, the upper edge 43 of the cylindrical portion 3 is welded to the peripheral portion of the upper lid body 11, and the lower edge 37 is welded to the upper edge of the annular portion 19 of the lower lid body 9. Again, it is desirable to facilitate fusion and sealing by using an annular welding assist plastic film.

FIG. 3 shows a porous core of the filtration device according to Example 1, (a) is a front elevational sectional view, (b) is a front elevational view, (c) a cc sectional view of FIG. It is a top view.
The details of the porous core 7 will be described with reference to FIGS. 1A and 3. The outer peripheral surface of the porous core 7 supports the inner peripheral surface of the pleated filter 5 and discharges the filtrate that has passed through the filter 5. Therefore, it has a passage 47 which is provided in a radial pattern so as to communicate with the internal passage 23 and constitutes a porous core. In order to increase the efficiency of the waste liquid, each of the passages 47 has a fan shape that is wide toward the outside as shown in FIG. The fan-shaped angle γ is made as large as possible within a range that does not hinder the support of the pleated filter 5. For the same purpose, a shallow recessed portion 49 extending in the circumferential direction and communicating with the passage 47 is formed on the outer peripheral surface of the porous core 7.
It should be noted in this example that the internal passage 23 and the flow passage 47 are extremely smaller than the internal passage in a normal filtration apparatus using a pleated filter. This is to reduce the residual liquid as much as possible. Preferably, the total volume of the internal passage 23 and the porous passage 47 is 50% or less of the total volume of the porous core 7, more preferably 30% or less, and even more preferably 15% or less. In the example of FIG. 3, it is about 10%. However, although it is necessary to ensure a sufficient flow rate, there is no problem at all in the embodiment.

  The pleated filter 5 is well known, for example, by a method described in Patent Document 1, a nonwoven fabric or a net support sheet is superimposed on both sides of a porous filtration membrane, folded into a pleat shape into a cylindrical shape, and both side edges are overlap-sealed. It is constituted by doing.

Referring to FIG. 1 (a), an example of assembling a filtering device with the above structure will be described. A porous pleat filter 5 is covered around a porous core 7, and a cylindrical portion 3 is further covered on the outside. Then, their upper ends are heated and welded and cooled to the melted inner surface of the upper lid 11. At this time, an annular plastic film may be used to assist welding. As a result, the upper edge of the pleated filter 5 is completely liquid-tightly sealed and the other members are integrated.
Next, a disc-shaped synthetic resin film 6 that can be fused to the lower end surface of the porous core 7, the pleated filter 5, and the cylindrical portion 3 is laminated and heat-sealed.
Next, the lower lid body 9 is put on the semi-finished product, and the lower end edge 37 of the cylindrical portion 3 and the cup-shaped upper end edge 43 are bonded by heat fusion. At this time, a disk-shaped plastic film may be used to assist welding.

Operation FIG. 1 is a completed filtering device according to this embodiment, and the outlet 17 is closed. The liquid to be filtered is introduced from the supply port 15, flows in the radial direction through the supply path 13, flows into the annular distribution flow path 21, and flows from the opening 35 of the lower end thin portion 33 of the cylindrical portion 3 to the lower end outer peripheral portion of the pleated filter 5. Subsequently, the flow is divided between the pleats and flows upward, and permeates through the porous filtration membrane of the pleat filter 5, and is collected as a purified filtrate in the discharge port 27 through the passage 47, the internal passage 23, and the discharge passage 25. Gels and solid particles are trapped on the outer surface of the filter. On the other hand, dissolved gas and bubbles are discharged from the annular distribution passage 21 of the supply passage 13 to the vent port 31 through the vent passage 41 and the annular vent passage 29. Gas rising from the periphery of the pleat filter 5 is drawn out from the lateral passage 45 to the annular vent passage 29.

  The distinguishing features of the present invention are that the pleat filter 5 is in direct contact with the inner surface of the cylindrical portion 3 and that the supply liquid is distributed and supplied directly from the lower end of the outer periphery of the pleat filter 5 to the pleats. As a result, the volume ratio of the flow path to the filtration device is much more suppressed than in the past, and the amount of residual liquid in the filtration device is reduced. Further, the gas vent is smoothly performed by the presence of the tapered surface 8 on the inner surface of the cylindrical portion 3.

  FIG. 4 shows a modification of the present invention. This embodiment shows a filtration device for processing a smaller amount of the liquid to be filtered, and the heights of the porous core 7, the pleat filter 5, and the cylindrical portion 3 are all lower than those of the first embodiment. . Other configurations and operations are the same as those in the first embodiment.

In this embodiment, the liquid supply port and the gas vent port are arranged on the side of the filtration device.
5A is a front elevational sectional view, FIG. 5B is a plan view, and FIG. 5C is an elevational sectional view. The filtration device 1 according to this embodiment includes a cylindrical part 3, a cylindrical pleat filter 5 inserted in contact with the inner wall of the cylindrical part 3 and whose upper and lower edges are sealed in a liquid-tight manner, and the pleated filter 5 includes a porous core 7 having a large number of openings that support the inner peripheral surface of the cylinder 5, and a lower lid body 9 and an upper lid body 11 that are liquid-tightly joined to both ends of the cylindrical portion 3. The upper and lower lids 9 and 11 together form a liquid-tight housing or liquid-tight container. The above structure is the same as that of Examples 1-2.

However, in this example, the lower lid body 9 does not have a filtrate supply port, and merely closes the lower end of the housing. Instead, the filtrate supply port 15 is provided in the lower part of the cylindrical portion 3 and communicates with the filtrate supply path 51. The supply path 51 passes through the cylindrical portion 3 and has an inner end opened in a tangential direction of the outer peripheral surface of the lower portion of the pleated filter 5. A lower end portion of the inner periphery of the cylindrical portion 3 is formed with a tapered surface 10 having an angle δ that expands toward the lower open end. As a result, a distribution path for the liquid to be filtered is formed between the outer peripheral surface of the pleated filter 5 and the tapered surface 10. This angle δ is made as small as possible without impeding the liquid distribution supply, thereby reducing the volume of the distribution path. For example, 5 to 20 degrees, for example, 10 degrees can be used as δ. On the other hand, the vent port 31 is provided in the upper part of the cylindrical portion 3 and communicates with the vent passage 53. Similarly, a tapered surface 8 having an angle β is provided along the inner peripheral surface on the upper end side of the cylindrical portion 3 to form a gas collection path with the outer peripheral surface of the pleated filter 5 and communicate with the vent passage 53. The angle β can also be used within a range that does not hinder gas venting, for example, 5 to 20 degrees.
Further, the lower end portion of the cylindrical portion 3 does not have the distribution path for the liquid to be filtered as in the first embodiment, and is merely welded to the lower lid body 9.
The structure of the porous core 7 is substantially the same as that described in FIG. 3, and the configuration of the pleated filter 5 is also the same.
Preferably, annular and disc-shaped plastic films may be interposed between the upper and lower end surfaces of the porous core 7 and the pleated filter 5 to assist welding with the upper and lower end plates.

In the operation of the filtration device according to this embodiment, the liquid to be filtered is introduced from the supply port 15, flows into the outer peripheral portion of the pleated filter 5 from the tangential direction through the supply path 51, and is formed by the tapered surface 10 on the inner surface of the cylindrical portion. From the distribution path, it is divided between the pleats, flows upward, and permeates through the porous filtration membrane of the pleat filter 5, and is collected as a purified filtrate in the discharge port 27 through the passage 47, the internal passage 23, and the discharge passage 25. . Gels and solid particles are trapped on the outer surface of the filter. On the other hand, dissolved gas and bubbles rise along a gas collection path formed between the outer peripheral surface of the pleated filter 5 and the tapered surface 8, and are discharged to the vent port 31 through the vent passage 53.
Even in this example, since there is no outer porous cylindrical support body having a large number of openings and a passage around it, the volume of the liquid flow path is greatly reduced as compared with a conventional filtration device using a pleated filter. In the case of a small amount of filtration, the amount of residual liquid in the filtration device can be greatly reduced.

  Referring to FIG. 6, in this embodiment, the liquid distribution path in Example 1 (FIGS. 1 to 3) is formed in the same manner as in Example 3 (FIG. 5). In this example, the filtrate distribution path communicating with the filtrate supply path 13 similar to that in FIG. 1 is formed by a divergent tapered surface 10 formed at the lower open end of the inner peripheral surface of the cylindrical portion 3.

1A and 1B show a filtering device according to a first embodiment of the present invention, in which FIG. 1A is a front elevational sectional view, FIG. 1B is a plan view, and FIG. 1C is a bottom view. FIG. 2 shows a cylindrical portion for constituting a part of the container of the filtration device according to the first embodiment, wherein (a) is a front elevational sectional view and (b) is a bottom view. FIG. 3 shows a porous core of the filtration device according to Example 1, (a) is a front elevational sectional view, (b) is a front elevational view, (c) a cc sectional view of FIG. It is a top view. It is front elevation sectional drawing which shows the filtration apparatus by Example 2 of this invention. The filtration apparatus is shown by Example 3 of this invention, (a) is front elevation sectional drawing, (b) is a top view, (c) It is elevation sectional drawing. It is front elevation sectional drawing which shows the filtration apparatus by Example 4 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Filtration apparatus 3 Cylindrical part 5 Pleated filter 7 Porous core 8 Tapered surface 9 Lower lid body 10 Tapered surface 11 Upper lid body 13 Filtration liquid supply path 15 Supply port 17 Residual liquid discharge port 19 Annular part 21 Distribution path (distribution flow) Road)
23 internal passage 25 discharge passage 27 discharge port 29 vent passage 31 vent port 33 thin portion 35 opening 37 lower end edge 39 inner wall surface 41 vent passage 43 upper end edge 45 lateral passage 51 supply passage 53 vent passage

Claims (9)

A cylindrical portion having a cylindrical inner space with both ends open, and a cylindrical portion that is inserted into the inner space in a state of direct contact with the inner wall of the cylindrical portion and whose upper and lower edge portions are liquid-tightly sealed. A pleat filter, a porous core having a large number of openings for supporting the inner peripheral surface of the pleat filter, and a lower lid that is liquid-tightly joined to both ends of the cylindrical portion and constitutes a liquid-tight housing together with the cylindrical portion A body and an upper lid, a filtered liquid distribution path that communicates between the pleats of the pleat filter from a lower end of the cylindrical section, a filtered liquid supply path that communicates with the distribution path, and a filtered medium connected to the supply path A filtration apparatus comprising: a liquid supply port; a filtrate discharge passage that communicates with an internal passage of the porous core; and a filtrate discharge port connected to the discharge passage. The filtration apparatus according to claim 1, wherein the filtrate supply port is provided in the lower lid body, and the filtrate discharge port is provided in the upper lid body. The filtration device according to claim 1, wherein the filtrate supply port is provided in the cylindrical portion, and the filtrate discharge port is provided in the upper lid. The lower end side of the inner peripheral surface of the cylindrical portion has a tapered surface that expands toward the lower open end, and the distribution path is defined by the tapered surface and the outer peripheral surface of the cylindrical pleated filter. The filtration device according to any one of claims 1 to 3. The lower lid is a cup-shaped member having an annular part having an inner diameter larger than the inner diameter of the cylindrical part, and the outer periphery of the lower end of the cylindrical part has a thin part that overlaps the annular part with a gap. The filtration device according to claim 1, wherein a through hole is formed in the thin portion, and the distribution path is configured by the gap and the through hole. The filtration device according to any one of claims 1 to 5, wherein a bottom edge of the pleated filter, a bottom surface of the porous core, and a bottom surface of the cylindrical portion are sealed with a single disc-shaped plastic sheet. The filtration apparatus according to any one of claims 1 to 6, wherein the volume occupied by the internal passage and the porous passage of the porous core is 50% or less of the entire volume of the porous core. The upper end side of the inner peripheral surface of the cylindrical portion has a tapered surface that expands toward the upper open end, and a gas collection path is defined by the tapered surface and the outer peripheral surface of the cylindrical pleated filter. The filtration device according to any one of claims 1 to 7, wherein a gas vent passage and a gas vent port communicating with the cylindrical portion or the upper lid are provided. The filtration device according to claim 8, wherein another gas vent passage connected to the gas vent passage from the filtrate supply passage is provided in the cylindrical portion.

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