JPH11253706A - Manufacture of pleat type filter cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a filtrate from being stained while pleats are effectively prevented from being bonded to each other by a method wherein a synthetic resin sheet is wound around an outer periphery of the pleat, fused in a ring state by pressure welding onto the outer periphery of the synthetic resin sheet with a heater to fusion weld a crest part of the pleat to the synthetic resin sheet, and the pleats are fixed to each other by leaving a space between them. SOLUTION: A pleated thermally fusible filter material 4 is wound on a perforated cylinder 1 by an ordinary method. Endless processing of the filter material 4 is preferably executed by a welding method. As material of the thermally fusible filter material 4, for example, polypropylene, polyethylene, polyester, nylon, etc., are mentioned. The thermally fusible synthetic resin sheet 5 is wound by one layer or a plurality of layers on the outer periphery of the pleat part 2 of the filter material 4. The synthetic resin sheet 5 has a water permeability, and preferably a filtering function. Many rink-like welded streaks 6 are formed on the outer periphery of the synthetic resin sheet 5, and a crest part of the pleat 2 is welded to the synthetic resin sheet 5 at a part of the welded streak 6 to fix the pleats 2, 2 to each other by leaving a space between them.

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD OF THE INVENTION

The present invention relates to a method for manufacturing a pleated filter cartridge in which folds are prevented from sticking to each other. More specifically, the present invention relates to an inexpensive pleated filter cartridge in which folds are prevented from sticking together without contaminating a filtrate. It relates to a manufacturing method.

[0002]

2. Description of the Related Art In order to secure a wide filtration area, a pleated filter cartridge formed by folding a sheet-like filter material into a fold is widely used in many fields.

[0003] The longevity of this pleated filter cartridge depends on how long the uniform spacing between the folds can be maintained during filtration.

[0004] In assembling a pleated filter cartridge, it is often not possible to maintain a completely uniform interval. In this case, Pascal's principle works immediately after the liquid has passed through the filter cartridge, and the liquid flows easily, that is, the liquid flows intensively at a wide fold interval, and does not flow much at a narrow place. As a result, as shown in FIG. 1, the crease interval is widened, and a dead portion 3 where the creases 2 and 2 are partially adhered to each other is generated.

[0005] When the dead portion 3 occurs, the filtration life is extremely shortened. Although it depends on the degree of adhesion, it is often reduced to 1/2 or 1/3.

When a predetermined pressure loss starts to occur due to clogging, the filter is replaced. When observing the degree of attachment of foreign matter to each fold of the replaced filter, it is found that there is a gap between the closely attached folds. It can be clearly seen that the liquid did not pass. That is, as in the case of a new article, almost no dirt is attached.

Conventionally, the following method has been used as a method for preventing such folds from adhering to each other.

(1) A method in which a net made of synthetic resin or metal is simultaneously folded together with a sheet-like filtering material in order to increase the strength of the fold.

(2) A method of pouring a plurality of adhesives into a ring shape to join the folds and the folds to prevent a change in the interval between the crests of the folds.

(3) A method in which an adhesive is applied to a band having a width of 5 to 15 mm, and the adhesive is wrapped around the ridge over multiple strips to prevent the folds from sticking to each other.

[0011]

The method of the above (1) is as follows.
Area that can be folded because of the thickness of the net (number of folds)
Becomes extremely small, and the cost greatly increases. In addition, when a metal net is used, the filtrate is contaminated by leaching from the metal, generation of rust, and the like.

In the method (2), since the filtrate is contaminated with the eluate from the adhesive, it cannot be used for filtration of chemicals, pure water, ultrapure water, etc., so that the range of use is limited.

The method (3) has a problem that the filtrate is contaminated similarly to the method (2).

The present invention has been made in view of such a point, and a method of manufacturing a pleated filter cartridge which effectively prevents adhesion of folds and does not cause inconvenience such as contamination of filtrate. The purpose is to provide.

According to the present invention, there is provided a method of manufacturing a pleated filter cartridge in which a hot-melt filter material folded in a pleated shape is wound around a perforated tube. A fusible synthetic resin sheet is wound, and a heater, preferably a heat roll having a raised portion is pressed against the outer periphery of the synthetic resin sheet and melted in a ring shape,
The ridges of the folds are fused to the synthetic resin sheet, and the folds are fixed at intervals.

In short, the present invention succeeds in firmly spacing and fixing the folds by winding the synthetic resin sheet and fusing it with the ridges of the folds.
The gist is to prevent contamination of the filtrate.

[0017]

Next, an embodiment of the present invention will be described with reference to the drawings. As shown in FIG. 2, the hot-melt filter material 4 that has been folded in a folded manner is wound around the perforated tube 1 by a conventional method. Endless processing of the filter medium 4 is preferably performed by a welding method that does not use an adhesive.

Examples of the material of the hot-melt filter material 4 include polypropylene, polyethylene, polyester, and nylon.

A single layer or a plurality of layers of a heat-fusible synthetic resin sheet 5 are wound around the outer periphery of the fold 2 of the filter medium 4.
The synthetic resin sheet 5 has water permeability, preferably a filtering function.

A large number of ring-shaped welding streaks 6 are formed on the outer periphery of the synthetic resin sheet, and the ridges of the folds 2 and the synthetic resin sheet 5 are fused at the portions of the welding streaks 6 to form They are fixed at intervals.

As shown in FIG. 3, the welding streaks 6 are formed by a metal heat roller 8 having a large number of ring-shaped protrusions 7 on the outer periphery.
Is preferably pressed against the synthetic resin sheet 5 and the roller 8 and the filter cartridge 9 are rotated in opposite directions to each other.

The metal heat roller 8 does not necessarily need to be rotated. Further, as shown in FIG. 4, the metal heat roller may be a semicircular metal heater 10, and its shape is not particularly limited as long as it has a projection.

The protrusions 7, 7 'contain a heater. After the entire roller is raised to a predetermined temperature by the heater, the raised portions (heaters) 7 and 7 ′ may be pressed against the rotating filter cartridge 9.

The number of welding streaks 6 to be formed is not particularly limited, but may be determined in consideration of the fold strength. The joining between the filter medium 4 and the plates 11 and 11 'at both ends is preferably performed by a welding method without using an adhesive.

Usually, a filter cover is attached to the outer periphery of the filter medium 4 to prevent breakage during handling.
In the present invention, since the synthetic resin sheet 5 plays the role, a filter cover may be omitted.

In the present invention, since the synthetic resin sheet is wound and welded, the adhesion of the folds can be prevented very effectively. According to the present invention, since the folds and the synthetic resin sheet are joined by welding, contamination such as elution of the adhesive component into the filtrate does not occur.

[0027]

As described above, according to the present invention, the adhesion between the folds can be effectively prevented, and the disadvantage that the filtrate is not contaminated and the like can be provided at a low cost. It has a remarkable effect that is not seen at all in the conventional method for manufacturing a pleated filter cartridge.

[0028]

[Brief description of the drawings]

FIG. 1 is a perspective view of a conventional pleated filter cartridge.

FIG. 2 is a partially cutaway perspective view of a pleated filter cartridge of the present invention.

FIG. 3 is a schematic perspective view showing a method for manufacturing a pleated filter cartridge of the present invention.

FIG. 4 is a schematic perspective view showing another manufacturing method of the pleated filter cartridge of the present invention.

[Explanation of symbols]

 Reference Signs List 2 fold 4 filter material 5 synthetic resin sheet 6 weld streaks 7 ring-shaped protrusion (heater) 7 ′ half-ring protrusion (heater) 8 metal heat roller 9 pleated filter cartridge 10 semicircular metal heater 11 plate 11 ′ Plate

Claims (4)

[Claims] 1. A method of manufacturing a pleated filter cartridge in which a hot-melt filter material folded in a fold shape is wound around a perforated tube, wherein a water-permeable and hot-melt synthetic resin sheet is wound around the outer periphery of the fold. A heater is pressed against the outer periphery of the synthetic resin sheet to melt it in a ring shape, the ridges of the folds are fused to the synthetic resin sheet, and the folds are fixed at intervals, wherein the folds are closely attached to each other. Of manufacturing a pleated filter cartridge that prevents the occurrence of bleeding. 2. The manufacturing method according to claim 1, wherein a large number of said heaters are arranged at intervals, and said heaters are pressed against an outer periphery of a synthetic resin sheet of a rotating filter cartridge. 3. A cylindrical or semi-cylindrical metal heater having a large number of ring-shaped or semi-cylindrical convex portions formed on the outer periphery thereof is pressed against the outer periphery of the synthetic resin sheet of the rotating filter cartridge. The method according to claim 2. 4. The pleated filter cartridge according to claim 1, wherein the endless processing of the filter material and the joining of the plate portions at both ends are performed by a welding method without using an adhesive.
The production method according to any one of the above.