JP4671974B2 - Filter cartridge - Google Patents

Description

  The present invention relates to a filter cartridge, in particular, a relatively large filter cartridge for general industry, for example, a liquid containing unnecessary components and impurities (hereinafter collectively referred to as “impurities”) in a flow process of a predetermined fluid. Or it is related with the filter cartridge for isolate | separating the said impurity etc. from gas.

  As a relatively large filter cartridge for general industries, a porous inner cylinder is formed inside the filter element formed by pleat-folding a belt-shaped filter medium and a porous outer cylinder is formed outside. There is known a structure in which concentric arrangements are made and resin-made disk-shaped end plates are joined and sealed to both end faces of a three-dimensional cylindrical structure.

As a method for joining the cylindrical structure and the end plate as described above, the end plate itself can be used in addition to the method in which a molten resin of the same material as the end plate itself is applied to the end plate and then both are pressed. Patented technology that is made of a thermoplastic resin material, heats and melts at least the part of the end plate that becomes the joint surface with the cylindrical structure, and joins them by the so-called welding or fusion method. It is proposed in Documents 1 and 2 etc.
JP-A-5-111622 Japanese Patent Publication No.8-17923

  However, in the system in which the end plate itself is heated and melted as described above, only the portion of the end plate that becomes the joint surface with the cylindrical structure is heated and melted locally. In the cooling process after joining, the end plate deforms not a little due to the difference in shrinkage between the melted part and the non-melted part. This deformation becomes more prominent as the outer diameter of the end plate becomes larger. Although it is allowed to some extent when the outer diameter is small, for example, when the diameter exceeds 100 mm, the deformation cannot be ignored and the filter cartridge is accommodated. This is not preferable because the mounting property to the casing and the appearance quality are impaired. Further, although it is effective to increase the thickness of the end plate in order to prevent the deformation, it causes an increase in the weight of the filter cartridge and a decrease in yield, which is not practical.

  The present invention has been made by paying attention to such a problem, and it is assumed that the end plate is heated and melted to be joined to the cylindrical structure. It is an object of the present invention to provide a filter cartridge that can be securely joined to the cylindrical structure without incurring any of them.

  According to the first aspect of the present invention, a porous inner cylinder is concentrically formed on the inner side of a filter element formed by forming a pleat-folded belt-shaped filter medium into a cylindrical shape, and a porous outer cylinder is concentrically formed on the outer side. It is presupposed that the filter cartridge has a structure in which a cylindrical end plate made of thermoplastic resin is joined and sealed to both end faces of the three-dimensional cylindrical structure.

  Then, a high fluidity resin layer having higher fluidity than the material of the end plate itself is integrally formed in advance on the part of the end plate that should become the joint surface with the filter element, The filter element and the end plate are joined by heating and melting at least a part of the high fluidity resin layer.

  In this case, in order to make the melting depth of the high fluidity resin layer constant and prevent the high fluidity resin layer from protruding, the filter element of the end plate as described in claim 2. An annular element receiving recess that is partitioned by an inner flange portion and an outer flange portion is formed in a portion to be a joint surface with the inner flange portion, and the inner flange portion and the outer flange portion are not in contact with the bottom surface of the element receiving recess portion. As described above, it is desirable that the high-fluidity resin layer is integrally formed in advance.

  Further, in order to prevent the end plate from being deformed and to efficiently melt the high fluidity resin layer, as described in claim 3, the fluidity of the material of the end plate and the fluidity of the high fluidity resin layer It is desirable that the MFR value (melt flow rate or melt flow index value, the unit is g / 10 min) is 20 or more as a difference from the property.

  In addition, the band-shaped filter medium described above includes, for example, a reinforcing auxiliary filter medium made of a resin net, net cloth, porous sheet, non-woven fabric, etc. on both the front and back surfaces of the polymer membrane. It is desirable to have at least a three-layer structure superimposed.

  Furthermore, in terms of the function of the filter cartridge itself, as described in claim 5, at least one of the end plates has a connection port with a seal member for connecting the inner space of the inner cylinder to the counterpart device. It is desirable that they are integrally formed.

  Therefore, in at least the invention described in claim 1, although a part of the end plate is heated and melted at the time of joining the filter element and the end plate, the end plate itself is formed in advance in two layers without melting. Only the high fluidity resin layer is partially heated and melted and then joined to the filter element. By doing so, it is possible to minimize the thermal influence on the end plate and suppress the deformation of the end plate.

  According to the first aspect of the present invention, when the end plate and the filter element are joined, only the high fluidity resin layer previously formed integrally with the end plate by two-layer molding is partially melted and joined. Therefore, compared to the case where the end plate itself is partially heated and melted, the deformation of the end plate can be greatly suppressed, and the attachment of the filter cartridge to the other casing and the appearance quality of the filter cartridge itself are improved. It can be good.

  According to the invention described in claim 2, since the high fluidity resin layer is previously formed integrally on the bottom surface of the element receiving recess formed in the end plate so as not to contact the inner flange portion and the outer flange portion. The heat-melting depth of the high-fluidity resin layer is constant, the protrusion of the high-fluidity resin layer can be prevented, the filter element is securely joined, and the appearance quality is much better. It will be a thing.

  According to the invention described in claim 3, since the MFR value is 20 or more as the difference in fluidity between the end plate and the high fluidity resin layer, the filter can be obtained only by partially heating and melting the high fluidity resin layer. There is an advantage that the joining with the element can be performed quickly and reliably.

  According to the invention described in claim 4, since the band-shaped filter medium which is the material of the filter element has at least a three-layer structure, there is an advantage that the filter element and the end plate can be more reliably joined by increasing the contact area. .

  FIG. 1 and the following drawings show a more specific embodiment of the filter element according to the present invention. In particular, FIG. 1 shows a sectional view of the entire relatively large filter cartridge for general industry described above. ing.

  The filter cartridge 1 shown in FIG. 1 has an inner tube 2 that is an inner cylinder and an outer tube 3 that is an outer cylinder arranged concentrically and is also annular in the annular space between the inner and outer cylinders 2 and 3. The filter element 4 is formed, and the cylindrical structure 5 is composed of the inner and outer cylinders 2 and 3 and the filter element 4. Then, disc-shaped end plates 6 and 7 having the same outer diameter as that of the outer tube 3 are disposed on both end faces of the cylindrical structure 5, and the filter element 4 has a high fluidity resin layer 8 as a bonding layer. The end plates 6 and 7 are joined and sealed.

  The filter cartridge 1 shown in FIG. 1 is of a type in which the fluid that flows in from the cylindrical surface side of the outer tube 3 is filtered by the filter element 4 and then flows out from the inner tube 2 side. Both are made of a thermoplastic resin material such as polypropylene (PP) in a lattice or porous shape, and have the necessary rigidity as the tubular structure 5 while having the permeability of the fluid to be filtered. . In addition, the code | symbol 2a shows the hole or hole-shaped space of the inner tube 2, and the code | symbol 3a shows the hole or hole-shaped space of the outer tube 3, respectively.

  In addition, both end plates 6 and 7 are formed of the same material as the inner tube 2 and the like (for example, the end plates 6 and 7 have a thickness of about 5 mm), and a portion that becomes a joint surface with the cylindrical structure 5 The annular element receiving recesses 6c and 7c are formed in advance with the inner flange portions 6a and 7a and the outer flange portions 6b and 7b, and the filter element 4 is a main element in the element receiving recesses 6c and 7c. It joins so that the cylindrical structure 5 may be received. And in the center part of one end plate 7, the boss | hub part 10 as a connection port with the sealing members 9, such as an O-ring for connecting the inner space of the inner tube 2 to the apparatus of the other party is integrally formed. It is.

  Here, on the bottom surfaces of the element receiving recesses 6c, 7c of both end plates 6, 7, an annular high-fluidity resin layer 8 having a predetermined thickness as a bonding layer is integrated in advance as shown in FIGS. Is formed. The high fluidity resin layer 8 employs a known two-layer molding method (two-color molding method) in which the same or different materials having affinity are injected simultaneously or with a time difference when molding the end plates 6 and 7 themselves. In this way, it is integrally formed with the end plates 6 and 7 in advance.

  In this embodiment, since the material of each end plate 6, 7 is polypropylene, when molding the end plates 6, 7, two types of polypropylene materials having different fluidity are injected to end plates 6, 7. The high-fluidity resin layer 8 is molded integrally with the end plates 6 and 7 using another polypropylene material having higher fluidity than the low-fluidity polypropylene material that will form itself.

  If the fluidity value of the polypropylene material of the end plates 6 and 7 is MFR value (melt flow rate or melt flow index value, the unit is g / 10 min), for example, 25, then the end plate 6 The fluidity value of the high fluidity resin layer 8 integrally molded by 7 and the two-layer molding method is 60 as the MFR value, and the difference between the two MFR values is 35. Although the difference between the two MFR values is not necessarily 35, it is desirable that the difference between the two MFR values is 20 or more in consideration of the bonding property with the filter element 4 and the like.

As shown in FIGS. 2 and 3, the thickness of the high fluidity resin layer 8 is equal to or slightly higher than the heights of the inner flange portions 6a and 7a and the outer flange portions 6b and 7b (high fluidity resin layer). 8 has a thickness of, for example, about 2 to 3 mm), so that the high fluidity resin layer 8 does not contact the inner flange portions 6a and 7a and the outer flange portions 6b and 7b. The portions 6b and 7b are molded with a predetermined gap C. The gap C is set to about 1 to 4 mm, for example.

  Then, a heat source such as a heater is opposed to the high fluidity resin layer 8 formed integrally with each of the end plates 6 and 7, and at least only the surface layer portion of the high fluidity resin layer 8 is heated and melted in advance. It joins with the filter element 4 by the side of the cylindrical structure 5 with welding or melt | fusion.

As shown in FIGS. 2C and 3B , stepped portions 3b are formed in advance on both end surfaces of the outer tube 3 for joining to the end plates 6 and 7, respectively. When the cylindrical structure 5 and the end plates 6 and 7 are joined, the outer flange portions 6b and 7b on the end plates 6 and 7 side and the stepped portion 3b on the outer tube 3 side are connected to each other with an uneven fitting. It is designed to fit.

  The filter element 4 is, as is well known, for example, a belt-shaped filter medium mainly composed of a polymer membrane is folded into a pleat shape (accordion pleat shape) and then rounded into a cylindrical shape, and both ends in the circumferential direction are joined. And shaped into an annular shape. The filter medium preferably has a composite structure in which a plurality of different types of filter mediums are overlapped. For example, a resin net, a net cloth, a porous sheet, a non-woven fabric, etc. The auxiliary filter medium for reinforcement to be used is made to have at least a three-layer structure. In addition to improving the filtration performance, the filter medium with such a composite structure has a low rigidity because the polymer membrane with the best filtration performance is extremely thin. Therefore, the filter element is reinforced to compensate for the rigidity of the polymer membrane. 4. Adopted for retaining the annular shape as 4.

  Next, the method for joining the cylindrical structure 5 and the end plates 6 and 7 will be described in a little more detail.

  First, as shown in FIGS. 2A and 2B, one end plate 6 previously molded integrally with the high fluidity resin layer 8 is set on a predetermined receiving jig 11 and positioned. The high fluidity resin layer 8 and the heater block 12 are opposed to each other, and at least the surface layer portion of the high fluidity resin layer 8 is melted and fluidized. As heating conditions, for example, the temperature of the heater block 12 is set to about 600 ° C., the distance from the high fluidity resin layer 8 is maintained to about 2 mm, and heating is performed for 30 to 40 seconds.

  Here, since the high fluidity resin layer 8 is secured in advance so as not to contact the inner flange portion 6a and the outer flange portion 6b as shown in FIG. By making the annular flat surface 12a of the heater block 12 having substantially the same diameter as 8 face each other, the entire surface of the high fluidity resin layer 8 can be melted with a uniform depth.

  On the other hand, when the high fluidity resin layer 8 is in contact with the inner flange portion 6a and the outer flange portion 6b without ensuring the gap C, a part of the heat received by the high fluidity resin layer 8 is obtained. Escapes due to contact with the inner flange portion 6a and the outer flange portion 6b, and the melt depth becomes smaller as the portion closer to the inner flange portion 6a and the outer flange portion 6b in the high fluidity resin layer 8 results in a higher height. Due to the non-uniformity of the melting depth of the fluid resin layer 8, the bonding with the filter element 4 tends to be insufficient.

  Then, as shown in FIG. 5C, the tubular structure 5 is pressed from above the end plate 6 while being positioned, and only the filter element 4 of the tubular structure 5 is joined to the end plate 6. 2 and 3, the holes of the inner tube 2 and the outer tube 3 or the hole-like spaces 2a and 3a are not shown.

  In this case, the inner tube 2 and the outer tube 3 forming the cylindrical structure 5 only have an uneven fitting with the inner flange portion 6a and the outer flange portion 6b on the end plate 6 side with the stepped portion 3b on the end face. When the molten and fluidized high fluidity resin layer 8 enters between the folds of the filter medium forming the filter element 4, the cylindrical structure 5 and the end plate 6 are firmly joined and fixed.

  Further, as described above, the gap C is secured in advance so that the high fluidity resin layer 8 does not come into contact with the inner flange portion 6a and the outer flange portion 6b. Even if it is changed, it does not protrude to the inner and outer peripheral sides of the cylindrical structure 5.

  When the joining of the one end plate 6 to the cylindrical structure 5 is finished in this way, it is set on the receiving jig 13 of the other end plate 7 in the same procedure as shown in FIG. Then, the high fluidity resin layer 8 is heated and melted by the heater block 12, and the cylindrical structure 5 in which the end plate 6 has been joined is pressed and joined as shown in FIG. Can obtain a filter cartridge 1 as shown in FIG. The seal member 9 is attached later.

  As described above, according to the present embodiment, it is assumed that the filter element 4 and the end plates 6 and 7 are joined after being heated and melted, but the deformation of the end plates 6 and 7 due to thermal contraction is suppressed. Thus, the filter cartridge 1 having excellent appearance quality can be obtained, and the filter cartridge 1 having a large diameter can be easily manufactured without deformation.

  In addition, in the said embodiment, although the material of the end plates 6 and 7 and the high fluidity resin layer 8 besides polypropylene was used for the inner tube 2 and the outer tube 3, this invention is not limited to these materials. If it is a thermoplastic resin, for example, a fluororesin, a polyethylene resin or the like may be used. In particular, when the end plates 6 and 7 are made of fluororesin (PFA), the high fluidity resin layer 8 is made of fluororesin (FEP) having higher fluidity and lower melting point than the end plates 6 and 7. It is desirable to do.

Cross-sectional explanatory drawing which shows a more specific example of the filter cartridge which concerns on this invention. Explanatory drawing which shows the joining procedure of the cylindrical structure and one end plate in the filter cartridge of FIG. Explanatory drawing which shows the joining procedure of the cylindrical structure in the filter cartridge of FIG. 1, and the other end plate.

Explanation of symbols

1. Filter cartridge 2. Inner tube (inner cylinder)
3. Outer tube (outer cylinder)
DESCRIPTION OF SYMBOLS 4 ... Filter element 5 ... Cylindrical structure 6 ... End plate 6a ... Inner flange part 6b ... Outer flange part 6c ... Element receiving recessed part 7 ... End plate 7a ... Inner flange part 7b ... Outer flange part 7c ... Element receiving recessed part 8 ... High fluidity resin layer 9 ... Sealing member 10 ... Boss part (connection port)

Claims (5)

A porous inner cylinder is arranged on the inside of a filter element formed by folding a belt-shaped filter material into a cylindrical shape, and a porous outer cylinder is arranged concentrically on the outer side, respectively, and consists of these three elements. A structure of a filter cartridge formed by joining and sealing a disk-shaped end plate made of a thermoplastic resin to both end faces of a cylindrical structure,
A high fluidity resin layer having higher fluidity than the material of the end plate itself is integrally formed in advance on the part of the end plate that should become the joint surface with the filter element by a two-layer molding method,
A filter cartridge, wherein the filter element and the end plate are joined by heating and melting at least a part of the highly fluid resin layer. Forming an annular element receiving concave portion partitioned by an inner flange portion and an outer flange portion in a portion to be a joint surface with the filter element in the end plate,
2. The filter cartridge according to claim 1, wherein a high fluidity resin layer is integrally formed in advance on the bottom surface of the element receiving recess so as not to contact the inner flange portion and the outer flange portion.   As the difference between the fluidity of the material of the end plate and the fluidity of the high fluidity resin layer, the MFR value (melt flow rate or melt flow index value, the unit is g / 10 min) is 20 or more. The filter cartridge according to claim 1 or 2.   The filter cartridge according to any one of claims 1 to 3, wherein the band-shaped filter medium has at least a three-layer structure in which a reinforcing auxiliary filter medium is superimposed on both front and back surfaces of the polymer membrane.   The connection port with a seal member for connecting the internal space of the inner cylinder to the counterpart device is integrally formed on at least one of the end plates. The filter cartridge described in 1.

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