JPH1147561A - Cartridge filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformize flux of a liq. passing through a filter membrane and to prevent clogging of the filter membrane from being generated by uniting physically the filter membrane provided around a core with at least one liq. permeable sheet and providing a cylindrical structure for making the liq. filtered with the filter membrane pass through inside of the core. SOLUTION: A filter membrane 13 being integrally made into a membrane with a liq. permeable sheet 14 is folded in pleats and is wound around a core 15a with a no. of liq. collecting holes 19a and a cylindrical structure 15b exists inside of the core 15a. This cylindrical structure 15b is not liq. hermetically bonded with an end plate 16b. In addition, a liq. is filtered from the primary side of the filter membrane to the secondary side and is passed through between the core 15a and the outer periphery of the cylindrical structure 15b from the liq. collecting holes 19a and is recovered through a liq. collecting hole 19b. In this case, a larger pressure is loaded on a liq. positioned relatively at lower part before filtering in comparison with a liq. positioned at upper part but as the filtered liq. is pushed up to the height of the liq. collecting hole 19b, the flux of the liq. passing through the filter membrane is made to be approximately the same flux.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cartridge filter used for filtering a liquid.

[0002]

2. Description of the Related Art Various types of filtration modules and filtration elements have been manufactured and sold in order to increase the filtration flow rate and facilitate handling at the time of filtration by a filtration membrane. One of the typical filtration elements is a cartridge type filter which is so-called pleated in which a filtration membrane is folded and housed in a cartridge having a fixed capacity. In this case, when a filtration membrane having a small flexural strength is used, breakage occurs during pleating and the function as a filtration membrane is lost. In order to remedy such inconveniences, in order to reinforce the conventional filtration membrane and also to serve as a spacer for preventing the filtration membrane surfaces from contacting each other, both sides of the filtration membrane are made of non-woven fabric or woven fabric, or a polymer or metal. The sandwich filter membrane obtained by scissors (for example, JP-A-60-58208) is pleated with a net formed by the above method.
Also known is a method of improving the strength of the filtration membrane itself by including a reinforcing material in the filtration membrane, such as Ultipore (manufactured by Pall Corporation).

[0003] When the purpose of filtration is to remove foreign substances in the liquid before filtration through a filtration membrane, the foreign substances include:
Garbage such as dust in ultrapure water, and bacteria and viruses for medical and food applications are examples. As is well known, a liquid after filtration can be obtained by a filtration operation in which a liquid before filtration is passed through a filtration membrane and foreign substances larger than the minimum pore size of the membrane are captured on the surface of the membrane or inside the membrane. In general, a surface of a filtration membrane that is in contact with the liquid before filtration is called a primary surface, and a surface that is in contact with the liquid after filtration is called a secondary surface.

[0004] The cartridge filter is generally used by being attached to a sealable container called a housing. Inside the housing, the cartridge filter is installed perpendicular to the ground. When the volume of the liquid before filtration is large, ten or more cartridge filters may be installed in the housing in parallel. The liquid before filtration enters the inside of the housing, is filtered from the primary side to the secondary side of the filtration membrane, and is collected from the outlet after passing through the core. At this time, the flux of the liquid passing through the filtration membrane can be distributed according to the gravity applied to the liquid before filtration with respect to the filtration membrane. This distribution becomes larger toward the lower part of the filtration membrane than to the upper part. Further, this distribution changes depending on the viscosity of the liquid before filtration and the resistance of the filter itself to the liquid before filtration.

[0005] The cartridge filter becomes unusable because it is clogged with components and foreign substances in the liquid before the filtration. The degree of clogging of the cartridge filter can be estimated by measuring the filtration pressure difference applied to the filtration membrane. In other words, it can be known from the difference between the pressure applied to the primary side and the pressure applied to the secondary side of the cartridge filter. The filtration differential pressure applied to the clogged cartridge filter may be as large as 4 kg / cm ² G or more. In such a case, depending on the performance of the liquid sending pump, the liquid before filtration may not be able to be sent, the filtration membrane may be broken, or the cartridge filter itself may be broken. As described above, the time from when the cartridge filter is used for filtration until the filtration differential pressure rises and the filter cannot withstand use, or the accumulated filtration amount is sometimes referred to as the filtration life.

[0006]

As described above, the liquid before filtration flows from the primary side to the secondary side of the filtration membrane through the shortest distance in the housing according to the gravity and the filtration resistance applied thereto. At the time of filtration, particularly at the initial stage, there is a case where almost no filtration pressure difference is applied to the filtration membrane. When the cartridge filter is placed perpendicular to the ground, the liquid to be filtered has a larger flux at the lower part at the upper part and at the lower part of the cartridge filter. When the filtration flux in the filtration membrane is large, the cumulative filtration amount tends to be smaller than when the filtration flux is small. For this reason, the filtration differential pressure increases from the lower part of the filtration membrane where the flux becomes relatively large.
In other words, clogging occurs from below the filtration membrane. When the cartridge filter is clogged in order from the bottom, the filtration life is shorter than when the cartridge filter is uniformly clogged.

[0007] From the viewpoint of prolonging the filtration life of a filtration membrane cartridge filter, the present inventors placed the cartridge filter horizontally with respect to the ground in order to make the flux of the liquid passing through the filtration membrane uniform. And a method of suspending a cartridge filter from the upper part of the housing, allowing the liquid before filtration to enter from the lower part of the housing, and collecting the liquid after filtration from the upper part. However, both
Although this is a method of reducing the influence of gravity applied to the liquid before filtration, the former filter cannot be expected to prolong the life of the filter inside the housing because the clogging occurs sequentially from the cartridge filter existing in the lower part of the housing. In the latter case, since a large amount of liquid before filtration remains inside the housing, the structure is inefficient from the viewpoint of using the liquid after filtration. Also,
The present inventors have found that if the flux of the liquid before filtration is reduced, the filtration life of the filtration membrane is extended as compared with the case where the flux is large,
As a method of reducing the flux and not reducing the amount of liquid after filtration, a method of increasing the number of cartridge filters existing in the housing has been considered, but in this case, equipment investment is increased.

[0008] An object of the present invention is to make the flux of the liquid passing through the filtration membrane of the cartridge filter uniform,
As a result, local clogging of the filtration membrane, particularly near the lower part in the direction of gravity, is prevented, and the life of the filtration membrane is extended, and a low-cost filter capable of maintaining the filtration performance of the cartridge itself for a long time. It is to provide a cartridge filter.

[0009]

DISCLOSURE OF THE INVENTION The above problem is solved in a cartridge filter having a core and a filtration membrane around the core, wherein the filtration membrane is physically fused with at least one liquid-permeable sheet, and This has been achieved by a cartridge filter having a tubular structure on an inner side for allowing the liquid filtered by the filtration membrane to pass therethrough. That is, the object of the present invention has been achieved by the following (1) to (11). (1) In a cartridge filter having a core and a filtration membrane around the core, the filtration membrane is physically fused with at least one liquid-permeable sheet, and the liquid filtered by the filtration membrane is provided inside the core. A cartridge filter having a cylindrical structure for allowing passage. (2) The upper end of the tubular structure is partially separated from the uppermost end plate and the other end is liquid-tight.
Cartridge filter. (3) The upper end portion of the tubular structure is entirely separated from the uppermost end plate, and the other end is liquid-tight.
Cartridge filter. (4) The cartridge filter according to claim 1, wherein the tubular structure is made of the same material as other constituent members of the cartridge filter. (5) The cartridge filter according to claim 4, wherein the material is made of polypropylene. (6) The cartridge filter according to claim 4, wherein the material is made of polyethylene. (7) The cartridge filter according to claim 1, wherein the cartridge filter is a pleated cartridge filter. (8) The cartridge filter according to claim 1, wherein the filtration membrane is made of polysulfone. (9) The cartridge filter according to claim 1, wherein the filtration membrane is made of nylon. (10) The cartridge filter according to claim 1, wherein the average pore size of the filtration membrane is 0.05 to 10 µm. (11) The cartridge filter according to claim 10, wherein the filtration membrane is formed using polysulfone represented by the general formula (1) or (2) as a raw material.

[0010]

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[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an example of a development view showing the entire structure of a general pleated cartridge filter. The filtration membrane 3 integrally formed with the liquid-permeable sheet is folded in a state where the liquid-permeable sheet 4 is present on the filtration membrane side, and is wound around a core 5 having many liquid collection ports 9. An outer guard 1 protects the filtration membrane outside. Perimeter guard 1, liquid-permeable sheet integrated filtration membrane 3,
The liquid-permeable sheet 4 and the core 5 are adhesively sealed by end plates 6a and 6b. The end plate is in contact with a seal portion of a filter housing (not shown) via a gasket (not shown). The liquid after filtration is collected from a liquid collecting port of the core and collected from an outlet (not shown). There are known cartridge filters of a gasket type having an outlet at both ends and an O-ring type at one end. Generally, a gasket type cartridge collects the filtered liquid from the outlet at the other end by sealing one end of the cartridge with a jig.

FIG. 2 is an example of a developed view showing the entire structure of a pleated filter cartridge filter having a tubular structure for making the flux of the liquid passing through the filtration membrane uniform in the present invention. The filtration membrane 13 formed integrally with the liquid-passing sheet is folded in a state where the filtration membrane side is in contact with the liquid-permeable sheet 14 and wound around a core 15 having a large number of liquid collection ports 19. It is wound around the core 15a. An outer guard 11 is provided on the outside to protect the filtration membrane. A cylindrical structure 1 is provided inside the core 15a.
5b is present. The outer peripheral guard 11, the liquid-permeable sheet-integrated filtration membrane 13, the liquid-permeable sheet 14, the core 15a and the tubular structure 15b are formed by end plates 16a and 16b.
Adhesively sealed. The tubular structure 15b is not liquid-tightly bonded to the end plate 16b (not shown). The filtered liquid comes into contact with a seal portion of a filter housing (not shown) via a gasket (not shown). The liquid after filtration is collected from a liquid collecting port of the structure, and collected from an outlet (not shown).

FIG. 3 is a schematic diagram showing one example of the flow of a liquid before and after filtration by a general cartridge filter. The outer peripheral guard 41, the filtration membrane 43, and the core 45 having a large number of liquid collecting ports are liquid-tightly bonded on the end plates 46a and 46b on the surfaces in contact with each of them. In a general filtration step, the primary side of the filtration membrane 43 is in contact with the liquid before filtration in the housing. The liquid that has passed through the outer guard 41 is filtered from the primary side of the filtration membrane 43 to the secondary side, and is recovered through the liquid collecting port 49 of the core 45. At this time, since the liquid before filtration has its own weight, the liquid located relatively below receives a greater pressure than the liquid located above, so that the filtration flux increases. In this way, the flux of the liquid passing through the filtration membrane is not uniform. That is, the above fluxes of (a1), (b1), and (c1) indicating the flow of the liquid near the upper end, near the center, and near the lower end are (a1) <(b1) <(c1). .

FIG. 4 is a schematic diagram showing one example of the flow of a liquid before and after filtration in a cartridge filter having a tubular structure for making the flux of the liquid passing through the filtration membrane uniform according to the present invention. It is. An outer peripheral guard 51, a filtration membrane 53 and a core 55 having a number of liquid collecting ports are provided with an end plate 56.
a and 56b are liquid-tightly adhered on the surfaces contacting each of them. The tubular structure 55b is liquid-tightly bonded to the end plate 56b.
And are not liquid-tightly bonded. In a general filtration process, the primary side of the filtration membrane 53 is in contact with the liquid before filtration in the housing. The liquid that has passed through the outer guard 51 is filtered by the filtration membrane 5.
3 is filtered from the primary side to the secondary side and passes through the liquid collecting port 59a of the core 55a. Next, the liquid passes through a space created between the core 55a and the outer periphery of the tubular structure 55b, and is collected from the outlet 58 via a liquid collecting port 59b at the upper end of the tubular structure 55b. At this time, since the liquid before filtration has its own weight, a relatively lower liquid is subjected to more pressure than a liquid located at the upper part. In the case of the cartridge filter having the cylindrical structure according to the present invention, the liquid filtered up to the level of the liquid collecting port 59b is pushed up. In this way, the flux of the liquid passing through the filtration membrane becomes substantially the same. That is, the above fluxes (a2), (b2), and (c2) indicating the flow of the liquid near the upper end, near the center, and near the lower end are (a2) ≒ (b2) ≒ (c2). .

It is desirable that the cross-section of the tubular structure that can be used in the present invention is point-symmetric. More preferably, it is circular. Such a cross-sectional shape helps uniform the flux in the circumferential direction of the filtration membrane. Further, the cylindrical structure that can be used in the present invention, the sum of the areas of the liquid passage ports at the upper end thereof is the cross-sectional area of the inner periphery of the core and the outer periphery of the cylindrical structure or the inner periphery of the cylindrical structure. 50% or more for any of the smaller areas 2
It is preferably at most 00%. More preferably 80
% Or more and 120% or less. If it is less than 50%, when the liquid after filtration is collected in the liquid collecting port, the regulation of the whole filtration is restricted, and the filtration resistance may be increased in the initial stage of using the cartridge filter. Also, 20
When it is larger than 0%, the effect of making the flux of the liquid before filtration uniform on the primary side of the filtration membrane is reduced, and the life of filtration of the cartridge filter as a whole may be reduced.

The material of the tubular structure that can be used in the present invention is desirably the same as the material constituting the cartridge filter except for the filtration membrane. When the same member is used, the cartridge filter can be assembled by welding using heat, ultrasonic waves, or the like. Since this method does not use an adhesive or the like, it is advantageous in that unnecessary components do not elute into the filtrate from the cartridge filter. A more preferred material having such advantages is polypropylene or polyethylene. Polypropylene and polyethylene have the advantage of being chemically stable and inexpensive. Further, cellulose triacetate and polysulfone can also be used as members constituting the cartridge filter. Cellulose triacetate is inexpensive, and polysulfone is characterized by excellent heat resistance.

The viscosity of the liquid before filtration that can be used in the present invention is 0.5 cP or more and 100 cP or less, more preferably 10 cP or less. In the case of a liquid having a viscosity exceeding 100 cP, the filtration resistance of the liquid before filtration to the filter becomes larger than the effect of the flux distribution due to gravity in the vertical direction of the cartridge filter, and the effect of the present invention is reduced. .

The filtration membrane that can be used in the present invention is:
Those having an average pore diameter of 0.05 to 10 μm are preferred.
Further, a material using a polysulfone represented by the following chemical formula (1) or (2) as a raw material is particularly preferable.

[0019]

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A method for forming the filtration membrane 3 using polysulfone pellets will be described below. That is, a polysulfone pellet is formed from formamide, dimethylformamide, dimethylacetamide, dimethylsulfoxide, 2-pyrrolidone,
It is dissolved in polar organic solvents such as N-methyl-2-pyrrolidone and sulfolane. The solvent may be a single solvent or a mixture of plural types of solvents. In order to adjust the dissolving power of the solvent, a small amount of a solvent such as alcohol, such as methanol, ethanol, propanol or butanol, or water, which is called a non-solvent or a poor solvent, is often added. The amount of addition depends on the type of solvent, but in the case of frequently used water,
It is from 0.05% by weight to 6% based on the film forming stock solution.

To the above-mentioned polysulfone solution, at least one kind of an inorganic electrolyte, an organic electrolyte, a polymer or the like, usually called a swelling agent or a foaming agent, for controlling the porous structure is added. Examples of the swelling agent that can be used in the present invention include hydrophilic polymers such as polyethylene glycol and polyvinylpyrrolidone, metal salts of inorganic acids such as salt, sodium nitrate, potassium nitrate, sodium sulfate, zinc chloride and magnesium bromide, sodium acetate, formic acid Organic acid salts such as sodium and potassium butyrate, polymer electrolytes such as sodium polystyrenesulfonate and polyvinylbenzyltrimethylammonium chloride, and ionic surfactants such as sodium dioctylsulfosuccinate and sodium alkylmethyltaurate are used. Some of these swelling agents alone show some effects even when added to the polymer solution, but when these swelling agents are added as an aqueous solution, they may show particularly remarkable effects. The addition amount of the swelling agent is not particularly limited as long as the uniformity of the solution is not lost by the addition, but it is usually 0.5% by weight to 35% by weight of the stock solution for film formation. The concentration of polysulfone as a film forming stock solution is 5 to 35% by weight, preferably 10 to 30% by weight.
When the amount exceeds 35% by weight, the water permeability of the obtained microporous membrane becomes so small as to have no practical meaning. When the amount is less than 5% by weight, a filtration membrane having a sufficient separation ability cannot be obtained.

The membrane-forming stock solution prepared as described above is cast on the water-permeable sheet, and the polymer solution membrane together with the water-permeable sheet is immersed in the coagulation solution immediately after casting or after a certain period of time. Water is most commonly used as the coagulating liquid,
An organic solvent that does not dissolve the polymer may be used, or a mixture of two or more of these non-solvents may be used. As the water-permeable sheet, a woven fabric, a non-woven fabric, and a net whose form is made of a synthetic polymer, a natural material, and a metal can be used. It is preferable that the material constituting the liquid-permeable sheet is the same as the material constituting the cartridge filter. It is preferable to use polypropylene or polyethylene as this material. If inconvenience occurs during film formation, a support for the liquid-permeable sheet can be used. As the support, a metal plate such as a copper plate or a stainless steel plate, a plastic sheet such as polyester or polyethylene, and a glass plate can be used. The casting membrane in which the polymer is precipitated in the coagulating liquid to form pores is washed with water, washed with warm water, washed with a solvent, etc., and dried, while being integrated with the liquid-permeable sheet.

A method for forming a polysulfone membrane having an inner minimum pore diameter, which is characterized in that it is hardly clogged, has a long-time filtration performance, and has a feature that the filtration layer is hidden inside the membrane and is not easily damaged, will be briefly described. A temperature of 15-60 ° C. and a relative humidity of 10-80 ° C. are applied to the surface of a liquid film obtained by casting a film forming stock solution on a support.
%, The air speed adjusted in the range of 0.2 to 4 m / sec.
There is an important technique for appropriately adjusting the amount of evaporation of the solvent vapor and the amount of absorption of the non-solvent vapor from the atmosphere (absorption of moisture) by exposure for 40 seconds. In such a preparation, for example, a casting solution is cast on a liquid-permeable sheet, and air at 25 ° C. and an absolute humidity of ₂ gH ₂ O / kg Air or more is applied to the casting surface at a wind speed of 0.2 m / sec or more. Thereby, the coacervation phase can be formed at a depth of 1 μm or more, preferably 1 to 30 μm from the outermost surface layer of the liquid film. Immediately thereafter, it is immersed in a coagulation liquid to form a porous film. In the film obtained in this manner, the deepest part of the part where coacervation has occurred becomes the minimum pore diameter layer. The pore size on the back surface is 10 to 10 with respect to the pore size on the front surface of such an inner minimum pore size layer film.
The specific surface area measured by the BET method is about 8 times.
８０80 m ² / g are obtained. A preferable specific surface area having both the mechanical strength and the filtration ability of the membrane is 20 to 60.
m ² / g. When the porosity of the membrane is increased, the permeability of water (liquid) is improved. However, when the porosity is too large, the membrane becomes brittle and cannot be used. Therefore, the preferred porosity is 55 to 87%, and particularly preferably 70 to 87%.
84%. The porosity of the membrane is greatly affected by the polysulfone concentration and the swelling agent concentration in the membrane-forming stock solution. When the polysulfone concentration is low and the swelling agent concentration is high, the porosity increases. It is slightly affected by the amount of water absorbed from the air immediately after film formation and the temperature of the coagulating liquid.

The filtration membrane 3 formed in this manner is subjected to a pleating process by a generally known method. Non-woven fabric, woven fabric, paper, and / or net are used as the liquid-permeable sheet 4. The folds of the filter media are cut off using a cutter knife or the like to cut the irregular portions at both ends in order to align both ends, and then rounded into a cylindrical shape. Or a liquid-tight seal using an adhesive. The general role of the liquid permeable sheet is firstly to guide the liquid to be filtered into the interior of the membrane folds so that the entire membrane folded into the cartridge can be used effectively for filtration. The second role of the liquid-permeable sheet is to protect the filtration membrane. Therefore, the liquid-permeable sheet is required to have a large number of voids and low liquid-permeation resistance, and an appropriate strength. Further, in the present invention, as a third role,
It has the role of easily releasing bubbles during filtration and increasing the contact area between the filtration membrane and the liquid.

The width of the pleat pleats is usually pleated so as to be 5 mm to 25 mm. In the present invention, the diameter is preferably set to 5 mm to 12 mm in order to easily release bubbles. In particular, it is preferable to set the thickness from 7 mm to 10.5 mm. There are several methods for the end sealing step depending on the material of the end plate. A method in which only the sealing surface of an already molded end plate is brought into contact with a hot plate or irradiated with an infrared heater to melt only the plate surface, and one end surface of the cylindrical filter medium is pressed against the molten surface of the plate and welded. Done. on the other hand,
When using a thermosetting epoxy resin for the end plate, pour the liquid of the prepared epoxy resin adhesive into the potting mold, pre-cure it, and make the viscosity of the adhesive moderately high. One end is inserted into the epoxy adhesive. After that, it is completely cured by heating. When the material of the end plate is a thermoplastic resin such as polypropylene or polyester, a method of inserting one end surface of the cylindrical filter medium into the resin immediately after pouring the molten resin into a mold is performed.

[0026]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to the contents of the examples. Synthesis Example 1 A membrane-forming example of a liquid-permeable sheet-integrated filtration membrane made of polysulfone is shown. Polysulfone (P35 made by Amoko)
00) 15 parts, N-methyl-2-pyrrolidone 70 parts, polyvinylpyrrolidone 15 parts, lithium chloride 2 parts, water 1.
Three parts were uniformly dissolved to prepare a stock solution. Also fineness 1.
A non-woven fabric sheet having a basis weight of 50 g / m ² was produced with 5d polypropylene. A support was placed under the non-woven fabric, and a film-forming stock solution was cast on the non-woven fabric sheet so that the thickness of the polysulfone membrane became 150 μm. Air was applied to the surface of the liquid film cast for 8 seconds and immediately immersed in a coagulation bath filled with water at 25 ° C. to obtain a microporous film. The bubble point of this membrane due to water is 150
kPa.

Example 1 The polypropylene nonwoven fabric of Synthesis Example 1 was brought into contact with the filtration membrane side of the liquid-permeable sheet-integrated filtration membrane of Synthesis Example 1 and pleated to a pleat width of 10 mm. The joint was sealed by welding. 5mm at both ends of the cylinder
Each was cut off and packed in the outer guard, which was connected in series. A polypropylene cylindrical structure, which is liquid-tight on the secondary side of the core and has a liquid outlet at the upper end, is placed inside,
It was welded and fixed to an end plate on the lower end side to complete a cartridge filter having a length of 80 cm. Using this cartridge filter, beer was filtered at 500 L / h. 3 until the filtration pressure difference reaches 1.0 kg / cm ² G
It took six days.

Comparative Example 1 The polypropylene nonwoven fabric of Synthesis Example 1 was in contact with the filtration membrane side of the liquid-permeable sheet-integrated filtration membrane of Synthesis Example 1 and pleated to a fold width of 10 mm. And the joint was sealed with an epoxy adhesive. The cylinder was cut off by 5 mm at each end, and the cut surface was sealed with an epoxy adhesive. Three of these are connected in series and the length is 80
cm cartridge filter. Using this cartridge filter, filtration of beer is performed at 500 L /
h. It took 30 days for the filtration pressure difference to reach 1.0 kg / cm ² G.

[0029]

According to the present invention, the filter life of the cartridge filter can be extended very easily and inexpensively. As a result, the cost of the process using the cartridge filter can be reduced. In particular, the effect is remarkable in a polysulfone anisotropic structure membrane cartridge filter in which the pore size on both surfaces of the membrane is twice or more the pore size of the smallest pore size layer inside the membrane.

[Brief description of the drawings]

FIG. 1 is a view illustrating a structure of a general pleated cartridge filter.

FIG. 2 is a drawing showing one example of the structure of a pleated cartridge filter in an embodiment of the present invention.

FIG. 3 is a drawing schematically showing the flow of a liquid before and after filtration by a general cartridge filter. The arrow in the figure is
Shows the direction of flow of the liquid before and after filtration.

FIG. 4 is a drawing schematically showing a flow of a liquid before and after filtration by a cartridge filter in an embodiment of the present invention. The arrows in the figure indicate the directions in which the liquid flows before and after filtration.

[Explanation of symbols]

 Reference Signs List 1 outer peripheral guard 3 liquid-permeable sheet integrated filtration membrane 4 liquid-permeable sheet 5 core 6a end plate 6b end plate 9 liquid collecting port 11 outer periphery guard 13 liquid-permeable sheet integrated filtration membrane 14 liquid-permeable sheet 15a core 15b cylinder -Like structure 16a End plate 16b End plate 19a Liquid collecting port 19b Liquid collecting port 41 Peripheral guard 43 Filtration membrane 45 Core 46a End plate 46b End plate 48 Outlet 49 Liquid collecting port 51 Peripheral guard 53 Filtration membrane 55a Core 55b Cylindrical structure 56a End plate 56b End plate 58 Outlet 59a Liquid collecting port 59b Liquid flowing port

Claims (11)

[Claims] 1. A cartridge filter having a core and a filtration membrane around the core, wherein the filtration membrane is physically fused with at least one liquid-permeable sheet, and the filtration membrane is filtered inside the core. A cartridge filter having a tubular structure for allowing a liquid to pass therethrough. 2. The cartridge filter according to claim 1, wherein an upper end portion of the tubular structure is partially separated from an uppermost end plate and the other end is liquid-tight. 3. The cartridge filter according to claim 1, wherein an upper end portion of the tubular structure is entirely separated from an uppermost end plate and the other end is liquid-tight. 4. The cartridge filter according to claim 1, wherein the tubular structure is made of the same material as other components of the cartridge filter. 5. The cartridge filter according to claim 4, wherein said material is made of polypropylene. 6. The cartridge filter according to claim 4, wherein said material is made of polyethylene. 7. The cartridge filter according to claim 1, wherein the cartridge filter is a pleated cartridge filter. 8. The cartridge filter according to claim 1, wherein said filtration membrane is made of polysulfone. 9. The filter according to claim 1, wherein said filtration membrane is made of nylon.
The cartridge filter according to 1. 10. An average pore size of the filtration membrane is 0.05 to 1
The cartridge filter according to claim 1, which has a thickness of 0 µm. 11. The cartridge filter according to claim 10, wherein the filtration membrane is formed using polysulfone represented by the general formula (1) or (2) as a raw material. Embedded image