JP4331629B2 - Cartridge filter for microfiltration - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a microfiltration cartridge filter used for filtering fine particles, bacteria, etc. in a liquid, and in particular, fine particles and bacteria contained in fruit juice used for producing soft drinks and the like in the food industry. The present invention relates to a microfiltration cartridge filter for removing water.

  Microfiltration membranes are used for separation and purification of microparticles and bacteria that exist in liquids in various fields such as the food industry, medical field, and electronics industry. In order to increase the amount of filtration per unit volume, cartridge filters obtained by pleating a microfiltration membrane are often used.

  Materials such as cellulose acetate, polysulfone, polyamide, and polytetrafluoroethylene are used as the microfiltration membrane constituting this cartridge filter, and materials such as polypropylene resin are used as the protector, tubular core, and end cap. (Patent Document 1).

  Further, as a cartridge filter using a non-woven fabric as a filter medium instead of a microfiltration membrane, there is a cartridge filter including a filter medium, a protector, a tubular core, and an end cap made of a polyester resin (Patent Document 2). Further, as a method for increasing the degree of locking between the protector and the tubular core and the end cap, it has been proposed to provide a groove at the end of the protector (Patent Documents 3 and 4).

Japanese Patent Laid-Open No. 11-47561 Japanese Unexamined Patent Publication No. 63-296807 Japanese Patent Publication No. 63-27968 JP-T-2002-519169

  However, in the case of a cartridge filter in which the protector and the tubular core described in Patent Document 1 are made of polypropylene, when the fruit juice used in the production of soft drinks and alcoholic beverages is filtered, the flavors contained in the fruit juice, in particular, monoterpene carbonization Hydrogen may cause the protector and the tubular core to swell and become longer, or the strength may decrease due to deterioration, and the liquid tightness between the end cap and the filtration membrane may be lost.

  In addition, when each member of Patent Document 2 is a cartridge filter made of a polyester resin, each member does not swell due to fruit filtration, but the filtration medium is a clarified filtration made of a nonwoven fabric, so the filtration accuracy is low, and the filter is not removed. High-precision microfiltration for the purpose of bacteria and the like cannot be performed.

  Furthermore, in Patent Documents 3 and 4, in order to enhance the melt adhesion between the protector and the tubular core and the end cap, a concave groove extending in the circumferential direction is formed at the end portion thereof to increase the adhesion area. However, this method is effective only when the protector and the material of the tubular core and the end cap are melt-adhesive, and in the case of a combination of materials without melt-adhesion, the cartridge filter is removed from the housing. Rotating with the protector may cause the protector to separate from the end cap and rotate or fall off.

  Therefore, the present invention does not lose the liquid tightness of the end cap and the microfiltration membrane even when the fruit juice is filtered, and the filtration accuracy is high, and the protector, the tubular core, and the end cap are firmly fixed. An object of the present invention is to provide a cartridge filter.

  In order to achieve the above object, the present invention provides a tubular core having a large number of liquid passage holes on the peripheral surface, a pleated microfiltration membrane provided on the peripheral surface of the tubular core, and the microfiltration membrane of the microfiltration membrane. Cylindrical protectors provided so as to cover the periphery, and these tubular cores, microfiltration membranes, and protectors are provided at both ends in the axial direction, and the microfiltration membranes are liquid-tightly sealed by thermal fusion with the microfiltration membranes. In the cartridge filter comprising an end cap, the tubular core, the microfiltration membrane, and the protector are all made of a thermoplastic polymer having monoterpene hydrocarbon resistance, and the end cap is made of the microfiltration membrane. And a resin having a melt-adhesive property, and the joint portion between the tubular core and the end cap of the protector is subjected to heat fusion with the microfiltration membrane. A concave portion is formed through which the molten resin of the end cap can flow, and the concave portion resists at least the circumferential and axial forces of the end cap when the resin of the poured end cap solidifies. It is the shape which is possible.

  In the cartridge filter for microfiltration according to the present invention, the tubular core, the microfiltration membrane, and the protector are all composed of a thermoplastic polymer having monoterpene hydrocarbon resistance, so that the filtration of fruit juice containing monoterpene hydrocarbon is performed. Also, these do not swell or deteriorate, and the liquid-tightness between the end cap and the filtration membrane is not lost and can be used stably for a long time. In addition, the recess formed in the joint between the tubular core and the end cap of the protector can resist at least the circumferential and axial forces of the end cap when the end cap is solidified. Because of the shape, the protector and the tubular core are firmly fixed to each other even if the protector and the tubular core are made of a material that does not have an adhesive property to the end cap. For this reason, when removing the cartridge filter from the housing, the protector does not separate from the end cap or fall off even if it is rotated with the protector. The microfiltration membrane and end cap must be made of materials with good melt adhesion to maintain liquid tightness, but the end is made up of microfiltration membrane with excellent filtration accuracy and material with good melt adhesion. The cap may have poor melt adhesion with the material constituting the tubular core and protector. However, even in such a case, the microfiltration cartridge filter according to the present invention provides the protector, the tubular core, and the end cap firmly by providing the concave portion at the joint between the tubular core and the end cap of the protector. Can be fixed to.

  As described above, according to the cartridge filter for microfiltration according to the present invention, even when the fruit juice is filtered, the liquid tightness of the end cap and the microfiltration membrane is not lost, the filtration accuracy is high, and the protector and the tubular core A cartridge filter for microfiltration in which the end cap is firmly fixed can be provided.

BEST MODE FOR CARRYING OUT THE INVENTION

  Next, an embodiment of a cartridge filter for microfiltration according to the present invention will be described with reference to the drawings. FIG. 1 is a partially cut perspective view of a cartridge filter for microfiltration according to the present embodiment. A cartridge filter 1 for microfiltration according to the present embodiment is used as a core, a tubular core 2 having a large number of liquid passage holes 8 on the peripheral surface, and a microfiltration membrane 4 provided on the peripheral surface of the tubular core 2. And a cylindrical protector 7 provided so as to cover the periphery of the microfiltration membrane 4, and axial ends of the tubular core 2, the microfiltration membrane 4 and the protector 7, so that the microfiltration membrane 4 is liquid-tight. And an end cap 10 for sealing.

  The tubular core 2 is preferably made of a polyester-based resin or a polyamide-based resin, which is a monoterpene hydrocarbon resistant material, and particularly preferably made of polybutylene terephthalate. The tubular core 2 is provided with a concave portion at the joint portion with the end cap 10 for mutual engagement with the end cap 10, and the shape and size of the concave portion is heat-sealed with the microfiltration membrane 4. The melted resin of the end cap 10 can flow in, and when the resin of the flowed end cap solidifies, it can resist at least the circumferential and axial forces of the end cap. The shape is not particularly limited as long as it is a shape, and includes a groove formed in the circumferential direction and the axial direction, a through hole, a groove formed in an oblique direction, and the like. For example, as shown in FIG. 2, the tubular core 2 is formed with the first groove 11 extending in the circumferential direction and the second groove 12 extending in the axial direction as the concave portions on the outer periphery of both end portions in the axial direction. Has been. The first groove 11 and the second groove 12 allow the resin in which the end cap 10 is dissolved to flow into the first groove 11 and the second groove 12 when the end cap 10 is heat-sealed to the microfiltration membrane 4. For example, the first groove 11 is provided over the entire circumference at a position of 1 to 2 mm from each end of the tubular core 2, or a plurality of first grooves 11 are provided at equal intervals in the circumferential direction. Yes. The width of the first groove 11 is preferably 1.5 to 2.5 mm, and the depth is preferably 25 to 50% with respect to the thickness 3 to 4 mm of the tubular core 2. When a plurality of first grooves 11 are provided, the lengths in the circumferential direction are preferably the same, and the total length of each of the first grooves 11 is formed to be ½ or more of the entire circumference. Is preferred. Moreover, it is preferable that the 2nd groove | channel 12 has a length of 1.5-4 mm from each both ends of the tubular core 2, and has a width | variety of 1-2 mm, and 1-8 pieces are formed in the circumferential direction. Is preferred. As these 1st groove | channels 11 and the 2nd groove | channel 12, what penetrated may be used and a some hole may be used. For example, FIGS. 2, 4 and 5 show a tubular core 2 having a first groove 11 formed over the entire circumference and a second groove 12 passing therethrough, and FIGS. 6 and 7 are equally spaced. 2 shows a tubular core 2 having two first grooves 11 formed at the same time and two second grooves 12 formed at equal intervals between the first grooves 11.

  The microfiltration membrane 4 is preferably made of polytetrafluoroethylene or polyamide, which is a monoterpene hydrocarbon-resistant material, and particularly preferably made of hydrophilic polytetrafluoroethylene. The microfiltration membrane 4 is sandwiched between support materials 3 and 5 and is folded together with the support materials 3 and 5 into a pleat shape to form a pleated filter material 6. The pleated filter medium 6 is formed in a cylindrical shape by adhering both axial ends thereof by heat sealing or the like. The support materials 3 and 5 are made of a polyester resin resistant to monoterpene hydrocarbons. The pleated filter medium 6 shown in FIG. 1 has a three-layer structure in which support materials 3 and 5 are arranged on the front and back surfaces of the microfiltration membrane 4. A configuration in which a plurality of layers are stacked and a plurality of support materials are stacked on the front and back surfaces thereof may also be used. Further, as the support materials 3 and 5, a nonwoven fabric, a net, a woven fabric, and the like can be used. However, when protecting the thin microfiltration membrane 4, the nonwoven fabric has good melt adhesion with the end cap 10. Is preferably used.

  The protector 7 is preferably made of a polyester-based resin or a polyamide-based resin, which is a monoterpene hydrocarbon-resistant material, like the tubular core 2, and particularly preferably made of polybutylene terephthalate. The protector 7 protects the pleated filter medium 6 and has a large number of liquid passage holes 9 on the peripheral surface thereof. Further, the protector 7 is provided with a concave portion at the joint portion with the end cap 10 in order to interlock with the end cap 10, and the shape and size of the concave portion are heat-sealed with the microfiltration membrane 4. The melted resin of the end cap 10 can flow in, and when the resin of the flowed end cap solidifies, it can resist at least the circumferential and axial forces of the end cap. The shape is not particularly limited as long as it is a shape, and includes a groove formed in the circumferential direction and the axial direction, a through hole, a groove formed in an oblique direction, and the like. For example, as shown in FIG. 3, a plurality of through holes 13 are provided at equal intervals in the circumferential direction at both ends in the axial direction of the protector 7. The through hole 13 is not particularly limited in the shape, number, size, and the like of the hole, and may be elliptical. For example, when the hole is circular, the center of the hole is preferably provided at 3 to 8 circumferential positions at 1.5 to 3.5 mm from both ends of the protector 7, and each diameter is 1 to 3 mm. It is preferable that Further, instead of these through holes 13, grooves extending in the circumferential direction and the axial direction as concave portions may be used.

  The end cap 10 has a liquid communication port that is aligned with the opening of the tubular core 2 at the center thereof, and is made of a resin having melt adhesion with the microfiltration membrane 4, such as a polypropylene resin. The end cap 10 is heat-sealed to the microfiltration membrane 4 by being pressed against both ends of the tubular body composed of the microfiltration membrane 4, the tubular core 2 and the protector 7 in a state where the back surface thereof is melted and sealed in a liquid-tight manner. The melted resin flows into the first groove 11 and the second groove 12 of the tubular core 2 and the through-hole 13 of the protector 7 and is solidified to be firmly fixed to the tubular core 2 and the protector 7. . In the microfiltration membrane cartridge filter according to the present invention, the melt adhesiveness means that it has adhesiveness when melted.

  Next, an example of a cartridge filter for microfiltration according to the present invention was prepared. In the cartridge filter for microfiltration according to the present embodiment, the tubular core 2 was made of polybutylene terephthalate having a thickness of 3.5 mm. The first groove 11 of the tubular core 2 has a width of 2.0 mm and a depth of 1.5 mm, and four grooves are formed at equal intervals in the circumferential direction at positions of 1.5 mm from both ends of the tubular core 2. . The lengths in the circumferential direction of these four first grooves 11 were formed to be the same, and the total of the respective lengths was formed to be ½ of the entire circumference. Moreover, the 2nd groove | channel 12 of the tubular core 2 was formed in the circumferential direction at equal intervals, and each length was 4 mm from the both ends of the tubular core 2, and the width | variety was 2 mm.

The microfiltration membrane 4 is made of hydrophilic polytetrafluoroethylene having a pore diameter of 0.45 μm, and the support materials 3 and 5 are made of polyester fiber and made of a nonwoven fabric having a basis weight of 100 g / m ^3. It was used. The pleated filter medium 6 is formed by attaching a mold at a temperature of 100 ° C. while folding the microfiltration membrane 4 and the support materials 3 and 5 sandwiched from the front and back surfaces into a pleated shape with a pitch of 15 mm / pitch, and both axial ends thereof. Were bonded to each other by heat sealing with heat of about 190 ° C. to form a cylinder.

  The protector 7 used was made of polybutylene terephthalate, which is a monoterpene hydrocarbon-resistant material, like the tubular core 2. As the through holes 13, four circular holes were formed at equal intervals in the circumferential direction. These through-holes 13 were formed so as to have a diameter of 2.5 mm at the center of 2 mm from both ends of the protector 7.

  The end cap 10 was made of polypropylene. The cartridge filter for microfiltration according to the present embodiment has an intermediate processing of the cartridge filter by assembling the tubular core 2 inside the cylindrical pleat filter medium 6 and the protector 7 outside, and cutting both ends of the pleat filter medium protruding from the protector 7. A cylindrical body was obtained. The end cap 10 heated and melted at a surface temperature of 230 to 300 ° C. is pressed and buried at both ends of the cylindrical body at 0.4 MPa, so that the first groove 11 and the second groove 12 of the tubular core 2 and the protector 7 A molten polypropylene resin was poured into the through hole 13 to produce a cartridge filter having a length of 10 inches (25.4 cm) and a diameter of 70 mm.

  Next, in order to perform the performance test of the cartridge filter for microfiltration according to this example, a comparative example was manufactured. The cartridge filter for microfiltration according to the comparative example is a polyethersulfone having a pore diameter of 0.45 μm as a microfiltration membrane, a polypropylene non-woven fabric as a support material for the front and back surfaces of the microfiltration membrane, and a polypropylene tubular core, protector and end cap A cartridge filter was produced in the same manner as in the example except that a groove was not provided in the tubular core and a through hole was not provided in the protector.

  Next, a performance test was performed on the cartridge filter for microfiltration membrane according to Examples and Comparative Examples. First, the cartridge filter for a microfiltration membrane according to Examples and Comparative Examples is immersed in a monoterpene hydrocarbon 1.0% diluted water at 90 ° C. for 40 hours, and the size, appearance, and completeness of the cartridge filter for microfiltration after immersion are immersed. I investigated. As a result, although the total length of the microfiltration cartridge filter according to the example was extended by 2 mm, the appearance was not changed, and as a result of the integrity test by the diffusion rate, the integrity was maintained without damage. On the other hand, the total length of the microfiltration cartridge filter according to the comparative example was extended by 10 mm, and the protector was swollen and deformed to peel off from the end cap. In addition, as a result of the integrity test using the diffusion rate, there was damage and the integrity was lost.

  In addition, the orange juice was filtered for 6 months using the cartridge filter for microfiltration according to Examples and Comparative Examples, and the size, appearance, and integrity of the cartridge filter were examined. As a result, the cartridge filter for microfiltration according to the example had an overall length of 3 mm, but the appearance was not changed, and as a result of the integrity test by the diffusion rate, the integrity was maintained without any breakage. On the other hand, it had a filtration accuracy of LRV7 or higher. In contrast, the cartridge filter for microfiltration according to the comparative example has an overall length of 15.3 mm, and the protector swells and deforms and peels off from the end cap. As a result of the integrity test using the diffusion rate, it is damaged and the integrity is lost. It was broken.

1 is a partially cut perspective view showing an embodiment of a cartridge filter for microfiltration according to the present invention. It is a perspective view of the tubular core used for this Embodiment. It is a perspective view of the protector used for this Embodiment. It is a partial notch partial enlarged front view of the tubular core used for this Embodiment. It is sectional drawing along the AA line of FIG. It is a figure corresponding to Drawing 4 showing other shapes of a tubular core. It is sectional drawing along the BB line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Cartridge filter 2 Tubular core 3, 5 Support material 4 Microfiltration membrane 6 Pleated filter material 7 Protector 8, 9 Liquid flow hole 10 End cap 11 First groove 12 Second groove 13 Through hole

Claims (3)

A pleated filter medium comprising a tubular core having a large number of liquid passage holes on the peripheral surface, a microfiltration membrane and a support material disposed on the front and back of the microfiltration membrane provided on the peripheral surface of the tubular core, and a cylindrical protector provided to cover the periphery, these tubular cores, provided at both axial ends of the pleats filter media and protectors, and an end cap for sealing liquid-tightly pleated filter media by thermal fusion of said pleat filter medium , Bei example, in a cartridge filter for filtering juice containing monoterpene hydrocarbons,
The tubular core and the protector are made of polybutylene terephthalate,
The microfiltration membrane is composed of hydrophilic polytetrafluoroethylene,
The support material is made of polyester fiber,
The end cap is made of polypropylene resin,
In the joint portion between the tubular core and the end cap of the protector, a recess is formed into which the resin of the end cap melted at the time of heat-sealing with the microfiltration membrane can flow,
A cartridge filter for microfiltration, wherein the concave portion has a shape capable of resisting at least the circumferential and axial forces of the end cap when the resin of the end cap that has flowed solidifies.   The cartridge filter for microfiltration according to claim 1, wherein at least one recess formed in the tubular core and the protector is a groove extending in a circumferential direction and an axial direction.   3. The cartridge filter for microfiltration according to claim 1, wherein the at least one recess formed in the tubular core and the protector is a plurality of through holes formed in the circumferential direction.

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