JP3822504B2 - Filter cartridge with gas vent - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a filter cartridge suitable for filtering a liquid. More specifically, the present invention relates to an amine-based organic stripping solution used for a substrate for manufacturing electronic components such as a semiconductor wafer or a glass substrate for manufacturing a liquid crystal device, and a pigment-dispersed photoresist used for a glass substrate for manufacturing a liquid crystal device. The present invention relates to a filter cartridge for filtering a chemical solution containing a large amount of foamable or vaporizable substances such as a slurry used in a chemical mechanical polishing apparatus and a liquid used in general industries.
[0002]
[Prior art]
In a typical filter cartridge, a cylindrical filter material in which a sheet-like filter membrane is cylindrically wound together with a net-like support, or a sheet-like filter membrane is folded together with a net-like support in a pleated shape many times at a constant width, The inner and outer surfaces of the cylindrical filter material formed into an endless shape and joined to the butted portion are supported by an inner cylinder and an outer cylinder made of resin having a large number of openings, and the upper and lower ends of the cylindrical filter material are supported. A filter element sealed with resin is used. The filter element is removably housed in a separate sealed housing (exchangeable) or joined together (disposable) and used for the desired filtration. The liquid to be filtered is supplied to the primary side between the outer cylinder of the filter element and the housing, and a part of the supply liquid is drawn through the filter membrane and into the secondary side passage which is the inner passage surrounded by the inner cylinder. As a purified stream, it is drawn out to the secondary outlet at the lower end, and the other part of the supply liquid goes out to the primary outlet together with the residual solid particles.
[0003]
In such a cartridge-type filtration device, if bubbles are present on the primary side and / or the secondary side, the bubbles block the pores of the filter membrane and the filtration efficiency decreases. That is, a pressure difference is applied between the primary side and the secondary side of the filter membrane to drive the filtrate through the fine pores of the filter membrane, but the liquid to be treated in which a component that easily vaporizes, such as hydrogen peroxide, is dissolved. In the case of filtration, the vaporizable component, which has been suppressed by the pressure on the primary side, is reduced in pressure on the secondary side to be vaporized to generate bubbles. Since bubbles adhering to the surface of the filter membrane accumulate as the filtration progresses, the bubbles eventually cover a large area of the inner surface of the filter membrane to inhibit the filtration, and the filtration efficiency is significantly reduced.
[0004]
In order to cope with this problem, gas vents are arranged in the primary side passage and the secondary side passage in the conventional filter cartridge. Since the conventional liquid inlet and filtrate outlet are provided on the lower side of the cartridge, the upper end of the filter element is closed by a cap. Therefore, as for degassing of the secondary side passage, as disclosed in Japanese Patent Application Laid-Open No. 7-326570, a gas vent pipe is inserted from the outlet of the secondary side passage to remove the gas accumulated at the upper end of the secondary side passage, or the upper end of the secondary side passage A gas vent port is provided to vent the gas to suppress the generation of bubbles.
On the other hand, in JP-A-8-192006, tubular portions for extending the secondary passage inside the filter element are integrally provided on the upper and lower end lids of the filter element, and these tubular portions extend to the outside of the housing through through holes in the housing. It describes that the mechanical strength is improved by irreversibly or permanently fixing the filter element to the housing by welding at the through hole. In this case, it is described that the upper one of the tubular parts penetrating is a secondary vent.
[0005]
[Problems to be solved by the invention]
However, the method disclosed in Japanese Patent Laid-Open No. 7-326570 is not very effective because it requires a gas vent pipe and a suction pump, which not only complicates the structure but also cannot sufficiently vent the gas from the gas reservoir. In addition, when the inlet / outlet of the liquid to be processed of the filter cartridge is generally provided at the upper end of the cartridge or at the lower side, if the cartridge is turned upside down, the gas vent port will be lowered so that bubbles cannot be removed. The posture is inconvenient because it can only accept a certain orientation.
On the other hand, Japanese Patent Application Laid-Open No. 8-192006 describes that the upper and lower sides of the secondary passage are drawn upward and downward of the housing and the upper lead pipe is used as a secondary vent. The lower passage is a filtrate discharge passage. It is not used as a secondary vent, and there is no description that the cartridge is used upside down. Furthermore, the technology of this publication irreversibly couples the filter element and the housing, but there is a problem that the thermal shock is applied and the filter membrane is easily distorted due to the stress applied to the rigid support portion of the housing and the filter element. On the contrary, it lacks durability.
[0006]
[Means for Solving the Problems]
The present invention has solved these conventional problems by providing the housing with secondary gas vent ports communicating with the upper and lower ends of the secondary passage inside the filter element.
Accordingly, the flexibility of degassing can be obtained even when the cartridge is turned upside down due to restrictions on the mounting location.
Furthermore, the present invention provides a durable filter cartridge that can relieve stress by supporting at least one of the filter elements with support means configured to allow relative movement between the filter element and the housing. can do.
[0007]
(1) More specifically, the present invention provides a cylindrical filter material, a resin-made inner cylinder that supports the inner surface of the filter material and has a large number of openings, and supports the outer surface of the filter material and a large number of openings. An outer cylinder made of resin, a filter element having a resin cap portion that seals the upper and lower ends of the cylindrical filter material, the inner cylinder, and the outer cylinder, and an airtight housing that houses the filter element The lower end portion of the housing is connected to a supply liquid inlet connected to a primary passage formed between the outer cylinder and the housing wall, and to a secondary passage formed by the inner wall of the inner cylinder. In the filter cartridge having a filtrate outlet, the filter element has first and second annular walls forming an extension of the secondary passage at the upper and lower ends. And Bei, wherein the housing comprises a first and a second cylindrical supporting wall for supporting respectively said first and second annular wall extending inwardly toward the annular wall, said housing further secondary The problem is solved by a filter cartridge comprising first and second secondary gas vent ports forming a vent passage extending outwardly of the housing from an extension of the passage.
[0008]
(2) According to a preferred embodiment of the present invention, in the above (1), the first and second primary gas vent ports communicating with the upper end and the lower end of the primary side passage respectively correspond to the upper end and the lower end corresponding to the housing. Is provided.
As a result, gas is vented from the primary side passage and the secondary side passage regardless of whether the filter cartridge is used in an upside-down position.
[0009]
(3) According to a preferred aspect of the present invention, in the above (1) or (2), at least one of the first and second annular walls corresponds to the first and second cylindrical support walls. The cylindrical support wall is hermetically sealed through a seal ring such as an O-ring. Preferably, one is sealed with a seal ring and the other is permanently fixed by welding, adhesion or the like.
If both sealing portions are formed by a seal ring, the work of assembling the filter element into the housing is facilitated, and in the case of an exchangeable filter cartridge, the work of exchanging the filter element is facilitated, and mechanical or thermal stress is applied. Can be mitigated and damage to the filter membrane can be avoided.
One of the first and second annular walls is hermetically sealed to a corresponding cylindrical support wall of the first and second cylindrical support walls with a seal ring, and the first and second annular walls are sealed. The form in which the other of the annular walls is hermetically fixed to the first and second cylindrical support walls is more preferable, and the mechanical strength is high and the stress can be relaxed. Can be provided. This type of filter cartridge is disposable because the filter elements are not replaceable.
In addition, it is good also as a disposable type by making it a fixed type, such as welding, which cannot disassemble the housing side regardless of the type of the filter element.
[0010]
(4) In a preferred embodiment of the present invention, in the above (1) to (3), if the first annular wall and the second annular wall are formed to have the same dimensions, the filter elements have the same upper and lower shapes and the same dimensions. Since it can be formed, there is no difference between the upper and lower sides of the filter element, and the work of assembling into the housing becomes easy. In the case of an exchangeable filter cartridge, the filter element can be easily replaced.
[0011]
When one of the first and second annular walls is fixed to one of the corresponding first and second cylindrical support walls, it may be directly welded as a butt structure. In the following description, an example of sealing using an O-ring and a case of using welding together will be described.
In this document, “upper” and “lower” are terms for convenience in conjunction with the drawing side of the inlet of the liquid to be processed and the outlet of the purified liquid in the accompanying drawings, and “first” in this document. And “second” are convenience terms given to those above and below, respectively, in the accompanying drawings.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The invention will be described in detail in connection with a preferred embodiment.
The filter cartridge of the present invention comprises a filter element and a housing for housing it. Each basic structure is well known and will not be described in detail, but will be described briefly.
[0013]
The housing has a disposable type in which the filter element is integrally formed and an exchange type in which the filter element can be exchanged. Appropriate thermoplasticity such as oxidation resistance, alkali resistance, chemical resistance and solvent resistance depending on the liquid to be treated A molded body made of resin can be used.
[0014]
The disposable type is a disposable type in which the lower housing portion made of resin and the upper housing portion incorporating the filter element are integrated by a method such as welding to each other, and cannot be reused.
[0015]
The replacement type housing has a resin lower housing part and an upper housing part that can be connected with a joint such as a screw or a sealing lock. By removing the joint, the lower housing part and the upper housing part are separated, and the filter Elements can be exchanged.
[0016]
A lower end portion of the housing is provided with a supply liquid inlet connected to a primary passage formed between the outer cylinder and the housing wall, and a filtrate outlet connected to a secondary passage formed by the inner wall of the inner cylinder. It has been.
[0017]
The filter element includes a cylindrical filter material, a resin inner cylinder that supports the inner surface of the filter material and has a large number of openings, a resin outer cylinder that supports the outer surface of the filter material and has a large number of openings, and a cylindrical filter A resin cap portion is provided for sealing the upper and lower ends of the material, the inner cylinder, and the outer cylinder. These structures are described in JP-A-5-111622 and JP-A-5-64728.
[0018]
The filter membrane has a wound type and a pleated type as described in the prior art, and the latter is preferable. As the material of the filter membrane, non-thermoplastic tetrafluoroethylene resin, thermoplastic polypropylene, polyethylene, polysulfone, polyamide, polycarbonate, polyethersulfone, vinylidene fluoride resin, and polyetherketone can be used. Select according to the liquid to be treated.
[0019]
Thermoplastic resins such as polypropylene, polyethylene, polysulfone, polyamide, polycarbonate, polyethersulfone, polyetherketone, and thermoplastic fluororesin can be used for the net-like support, inner cylinder, outer cylinder, upper and lower caps, and housing materials. However, it selects according to a to-be-processed liquid.
[0020]
According to the present invention, a through hole is provided in the upper end cap of the secondary side passage and communicates with a gas vent port provided in the upper end portion of the housing. The upper end portion of the gas vent port protrudes from the upper end portion of the housing, and the bubble gas is separated by a gas trap inserted in a pipe connected to the gas vent port, and the remaining liquid can be returned to the inlet of the housing and circulated. A lower end portion of the gas vent port forms a cylindrical support wall extending downward from the upper end portion of the housing.
[0021]
The filter element is provided with a first annular wall forming a part of the secondary passage at the upper end, and an O-ring such as silicon rubber is attached to the outer periphery thereof. This annular wall is fitted into a cylindrical support wall extending downward from the upper end of the housing and hermetically sealed by an O-ring.
[0022]
The filter element also includes a second annular wall forming a part of the secondary side passage at a lower end, and a second lower end of the housing receives the second annular wall hermetically through an O-ring. A cylindrical support wall is formed. In particular, if the second annular wall is formed in the same size as the annular wall at the upper end of the filter element, the vertical direction is lost and this is convenient for assembly.
A gas vent port can also be provided at the upper end of the primary passage of the housing.
[0023]
【Example】
Example 1
FIG. 1 is a cross-sectional view of a filter cartridge according to an embodiment of the present invention.
The filter element 1 is preferably a pleated cylindrical filter material 3, a resin inner cylinder 5 supporting the inner surface of the filter material and having a large number of openings 27, and a resin material supporting the outer surface of the filter material and having a large number of openings 25. The outer cylinder 7, the cylindrical filter material 3, the inner cylinder, and the resin caps 9 and 11 that seal the upper and lower ends of the outer cylinder are provided. These members are hermetically coupled by welding or other coupling means.
[0024]
The housing 13 is formed by hermetically welding the upper housing portion 15 and the lower housing portion 17 at the welding portion 19 after the filter element 1 is assembled. An inlet 21 for the liquid to be processed and an outlet 33 for the filtrate are formed at the lower end of the housing, and the liquid to be processed is formed between the inlet 21 and the outer peripheral surface of the filter element 1 and the inner wall of the housing 13 in order from the pump. The flow passes through the opening 25 of the outer cylinder 7, is filtered by the cylindrical filter material 3, and the filtrate passes through the opening 27 of the inner cylinder 5. Then, it passes through the passage 31 and flows out from the outlet 33 as a purified liquid.
[0025]
The upper cap 9 of the filter element 1 is provided with an annular wall 41 protruding upward, which fits into a cylindrical support wall 45 constituting the lower part of the gas vent on the housing 13 side and is hermetically sealed by an O-ring 43. Is held in. The inner diameter of the cylindrical support wall 45 is the same as or slightly larger than the outer diameter of the annular wall 41. As a result, bubbles can be raised by buoyancy without retaining bubbles on the inner wall surface of the filter membrane. The inner diameter of the annular wall 41 is the same as the diameter of the inner wall of the inner cylinder 5 and forms a part of the secondary side passage 29. A secondary side gas vent port 39 constituting an upper portion of the gas vent protrudes upward from the housing 13. A primary gas vent 35 is also provided at the upper end of the primary passage.
[0026]
The lower cap 11 of the filter element 1 is provided with an annular wall 47 projecting downward, which is fitted to a cylindrical support wall 51 on the housing 13 side and is hermetically held by an O-ring 49.
Preferably, both annular walls 41, 47 are formed to the same size and shape, thereby simplifying manufacture and assembly.
[0027]
The inner diameter of the cylindrical support wall 51 is the same as or slightly larger than the outer diameter of the annular wall 47. Accordingly, when the filter cartridge is used upside down, bubbles can be raised toward the gas vent port 39 ′ by buoyancy without bubbles remaining on the inner wall surface of the filter membrane. The inner diameter of the annular wall 47 is formed to be the same as the diameter of the inner wall of the inner cylinder 5 and forms a part of the secondary side passage 29.
[0028]
Further, a secondary side gas vent port 39 ′ projects downward from the housing 13. A primary side gas vent port 35 ′ is also provided at the lower end of the primary side passage for venting gas when the filter cartridge is used upside down.
The gas vent ports 35, 35 ', 39, 39' are hermetically sealed with a suitable lid (screw cap, lock cap, etc.) when they are on the lower side.
[0029]
Since it is the above structure, the gas already generated in the primary side channel goes out to the primary side gas vent port 35 by buoyancy. The primary side gas vent port can also be connected to an appropriate pipe line having a throttle valve and a gas trap so as to maintain the primary side pressure. Further, since the filtrate coming out to the secondary passage 29 through the filter element 1 is depressurized, the gas dissolved therein is vaporized into bubbles, but rises by buoyancy and is surrounded by the cylindrical support wall 45. It gathers in the chamber 53 and then exits from the secondary side gas vent port 39. In this way, the bubbles continuously exit from the gas vent ports 35 and 39.
[0030]
In addition, when it is necessary to use the filter cartridge upside down due to circumstances such as discomfort of the apparatus, the gas vent ports 35 and 39 are closed and the gas vent ports 35 ′ and 39 ′ are opened. The operation is the same as described above.
[0031]
According to the above structure, even if the filter cartridge is used in an arbitrary vertical relationship, the air bubbles generated in the primary side passage 23 and the secondary side passage 29 are continuously collected in the gas vent port 35 and 39 (35 'and 39' when inverted) is pulled out.
[0032]
Further, according to the above structure, the filter element can be easily obtained by fitting the outer periphery of the annular wall 41 provided at the center of the upper cap 9 to the cylindrical support wall 45 on the housing side through a sealing means such as an O-ring. 1 can be hermetically fixed to the housing 13. Furthermore, the lower end portion of the filter element 1 is also an annular wall 47 and can be supported by the cylindrical support wall 51 via the sealing means 49. In this case, the diameter is the same as that of the upper annular wall 41. In addition, the assembly efficiency can be increased.
[0033]
Example 2
FIG. 2 shows an example of a replaceable filter cartridge. Members having the same structure as in FIG. 1 are given the same reference numerals. The filter element 1 has the same structure as that shown in Example 1.
[0034]
The characteristic part of the housing has the same structure as that of the first embodiment, but differs in that the upper housing part 55 and the lower housing part 57 are detachably coupled. That is, the lower end of the upper housing part 55 is enlarged and a female screw part 61 is formed on the inner peripheral surface, and a male screw 63 is formed on the outer peripheral surface of the upper end part of the lower housing part 57 and screwed into the female screw part 61.
[0035]
Example 3
FIG. 3 shows another example of the exchangeable filter cartridge. Members having the same structure as in FIG. 1 are given the same reference numerals. The filter element 1 has the same structure as that shown in Example 1.
[0036]
The characteristic portion of the housing has the same structure as that of the first embodiment, but differs in that the upper housing portion 71, the intermediate cylindrical housing portion 73, and the lower housing portion 75 are detachably coupled to each other. That is, the outer peripheral flange portion of the upper housing portion 71 and the intermediate housing portion 73 are coupled by the fastening band 70 in contact with the abutting surface 69, and the outer peripheral flange portion of the lower housing portion 75 and the intermediate housing 73 is the abutting surface 65. In contact with each other, they are connected by a fastening band 67.
[0037]
Further, in this embodiment, the inlet 21 of the liquid to be processed and the outlet 33 of the filtrate are provided at the lower end of the filter cartridge. However, when the filter cartridge is used upside down, the gas vent ports 35 and 39 are closed. And providing the bubble trap is the conduit that connects to the outlet 33 of the inlet 21 and filtrate. As a result, the inlet 21 and the outlet 33 of the filtrate also serve as a gas vent port.
[0038]
Example 4
FIG. 4 shows another preferred embodiment of the present invention. In this example, an annular wall 41 is formed on the upper end of the upper lid of the filter element 1 so as to protrude upward, and is connected to the seam 83 and the seam 84 from the upper part of the housing having the body 80, the upper part 81 and the lower part 82. Cylindrical support walls 45 are formed and are sealed to each other via seal rings 43 on opposite surfaces. Since this part enables a minute shift of the mutual position even in the assembled form, the stress is relieved. On the other hand, an annular wall 47 is formed on the lower surface of the lower lid of the lower end of the filter element 1 so as to protrude downward. In this example, the diameter is larger than that of the annular wall 41, but the diameter may be the same. Further, the cylindrical support wall 51 rises from the lower portion 82 of the housing, and is hermetically welded to the lower surface of the annular wall 47 and the abutting portion 85. This part increases the mechanical strength of the filter cartridge. As described above, in this embodiment, it is possible to alleviate the occurrence of stress that is likely to occur in use at high temperature as well as mechanical strength, thereby preventing the filter membrane from being damaged and improving the durability of the filter cartridge. .
[0039]
【The invention's effect】
According to the present invention, the first and second gas vent ports communicating with the upper and lower ends of the secondary passage inside the filter element are provided in the housing. It can be continuously drawn out from the gas vent port without accumulating on the surface, and the filtration efficiency can be increased.
[0040]
The filter element has an annular wall that forms part of the secondary passage in the upper end cap, while the lower end of the gas vent port of the housing forms a cylindrical support wall that hermetically receives the annular wall. As a result, the annular wall of the filter element can be supported by the cylindrical support wall of the housing, making assembly and replacement easy.
[0041]
In particular, the fourth embodiment provides the advantage that mechanical strength and mainly the effect of stress relaxation can be obtained.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a first embodiment of the present invention.
FIG. 2 is a schematic cross-sectional view of a second embodiment of the present invention.
FIG. 3 is a schematic cross-sectional view of a third embodiment of the present invention.
FIG. 4 is a schematic sectional view of a fourth embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Filter element 3 Filter material 5 Inner cylinder 7 Outer cylinder 9 Upper cap 11 Lower cap 13 Housing 15 Upper housing part 17 Lower housing part 19 Welding part 21 Supply flow (processed flow) inlet 23 Primary side passage 25 Outer side cylinder Opening 27 Opening of inner cylinder 29 Secondary side passage 31 Outlet passage 33 Outlet 35, 35 'Primary side gas vent port 39, 39' Secondary side gas vent port 41, 47 Annular wall 43, 49 O-ring 45, 51 Cylindrical support wall 53 Gas vent chamber 55 Upper housing part 57 Lower housing part 59 Enlarged part 61, 63 Screw part 65, 69 Flange contact surface 67, 70 Fastening band 71 Upper housing part 73 Intermediate housing part 75 Lower housing part

Claims (8)

Cylindrical filter material, resin inner cylinder supporting the inner surface of the filter material and having a large number of openings, resin outer cylinder supporting the outer surface of the filter material and having a large number of openings, and the cylindrical filter And a filter element having a resin cap portion for sealing the upper and lower ends of the inner cylinder and the outer cylinder, and an airtight housing containing the filter element. In a filter cartridge having a supply liquid inlet connected to a primary side passage formed between a cylinder and a housing wall, and a filtrate outlet connected to a secondary side passage formed by the inner wall of the inner cylinder, The filter element includes first and second annular walls that form an extension of the secondary passage at an upper end and a lower end, and the housing is the annular Comprises a first and a second cylindrical supporting wall for supporting respectively said first and second annular wall extending inwardly toward the outer side of the housing from said housing further extension of the secondary passage A filter cartridge comprising first and second secondary gas vent ports forming a vent passage extending in the direction. 2. The filter cartridge according to claim 1, wherein first and second primary gas vent ports communicating with the upper and lower ends of the primary passage are respectively provided at the corresponding upper and lower ends of the housing. 2. At least one of the first and second annular walls is hermetically sealed to a corresponding cylindrical support wall of the first and second cylindrical support walls via a seal ring. Or 2 filter cartridges. The at least one of the first and second annular walls is in an inter-insertion relationship with a corresponding cylindrical support wall of the first and second cylindrical support walls, and between the opposing faces of the insertion portion. 4. The filter cartridge according to claim 3, wherein the filter cartridge is hermetically sealed by an intervening seal ring. The filter cartridge according to any one of claims 1 to 4, wherein the other of the first and second annular walls is hermetically fixed to the first and second cylindrical support walls. The other of the first and second annular walls is in an abutting relationship with the corresponding cylindrical support wall of the first and second cylindrical support walls and is hermetically fixed at the abutting portion. The filter cartridge according to claim 5. 5. The filter cartridge according to claim 1, wherein the first and second annular walls are detachable from the first and second cylindrical support walls, and the filter element can be replaced. The filter cartridge according to any one of claims 1 to 6, wherein the filter element is a disposable type in which the other one of the first and second annular walls of the filter element is fixed to the housing, or the joint of the housing is airtightly fixed.

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