JP3097828B2 - Filter element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a filter element suitable for industrial dust collection or environmental dust collection.
More particularly, the present invention relates to a filter element suitable for collecting dust from incinerator exhaust gas and other fine particles in high-pressure gas, which require heat resistance.

[0002]

2. Description of the Related Art As a conventional filter element, as shown in FIG. 16, a woven fabric, a non-woven fabric or a molded product thereof is used, and a pair of the woven fabric, the non-woven fabric and the molded body are faced to each other (or one sheet is folded). A flat box having a structure in which filter materials 51 and 52 are provided, and the flat ends 53 of the outer margins of the respective filter materials 51 and 52 are joined in a state of facing each other to form a bag shape or an internal space. (See Japanese Patent Application Laid-Open No. 5-277321). The flat ends 54 of the filter media 51 and 52 are sewn and joined with a sewing thread 53 in an overlapped state, but the joining means may be adhesion, fusion, screwing, stapling, or the like in addition to sewing. Caulking and the like are known.

[0003] The flat box-shaped filter element 50 comprises:
Since the filters can be arranged in parallel in a can body (not shown) at a narrow interval, the filtration area per installation area can be made larger than that of a cylindrical filter element (such as a bag filter). In particular, when the surfaces of the filtering materials 51 and 52 are formed in a corrugated or pleated shape, the filtering area can be further increased.

On the other hand, as a mechanism for removing dust and the like collected by the filter element 50, there are a mechanical vibration type, a back pressure type, a pulse jet type, and the like. Because it does not require
The pulse jet method is most often used. The method is 5 kgf / cm instantaneously (about 0.1 seconds).
Compressed air of about ² G is blown into the filter element in the direction opposite to the direction of the filtration wind, and the pressure impact and the filtering materials 51, 5
Due to the expansion of 2, the collected matter deposited on the surfaces of the filter media 51 and 52 is wiped off (hereinafter, referred to as a back washing process).

[0005] According to the above-described back-washing treatment by the pulse jet method, the collected matter collected by the filter element 50 can be washed off with high efficiency.
It also has the disadvantage that the physical load on the elements 1, 52 is large and adversely affects the strength. That is, the filter media 51 and 52 of the element contract by suction or pushing pressure at the time of filtration, and expand rapidly by the action of compressed air at the time of backwashing. In addition, in the case where the surfaces of the filtering materials 51 and 52 are formed in a corrugated shape as in the case of the filter element 50, when the filtering materials 51 and 52 return to their original shapes during the filtering process after the backwashing process, they face each other. Filter material 5 to contact
There is a possibility that the positions of the concave portions 1 and 52 are shifted and the internal space is collapsed.

Therefore, as shown in FIG.
When the surfaces of the filter members 1 and 52 are formed in a corrugated shape, the concave portions 51a and 52a of the respective filter media 51 and 52 are sewn together with sewing threads 53 and joined. Thereby, the filtering material 51,
The displacement of the concave portions 51a and 52a of the 52 can be prevented. Thus, the recesses 51a, 52 of the filter media 51, 52
a By joining the members to each other, it is possible to prevent the internal spaces of the filter media 51 and 52 from being crushed due to the repetition of the filtration process and the back washing process, and to increase the rigidity of the respective filter media 51 and 52. it can.

[0007]

However, the filter element 50 formed into a waveform is subjected to the filtering process and the backwashing process so that the compressive stress at the time of the filtering process is applied to the joints of the concave portions 51a, 52a and the flat end portion 54. And the tensile stress at the time of the back washing process acts repeatedly. Then, the concave portions 51a,
The strength of the sewing thread 53 as a joining means for joining the 52 a and the flat end portion 54 exceeds the strength of the filter media 51 and 52.

[0008] Therefore, when repeated stress is generated at the joint, there is a possibility that a crack may be generated near the hole sewn for joining to cause breakage. Of course, the same applies to the case where other joining means such as adhesion, fusion, screwing, stapling and caulking are used. In particular, the tendency is remarkable in the case of the self-supporting filter media 51 and 52 having a certain degree of rigidity as shown in FIG.

In such a case, the damage is caused by the filter media 51, 52.
Since it depends on the strength of itself, simply increasing the strength of the joint does not solve the problem. In addition, there is a fundamental problem that when a hole is opened and joined as in sewing or the like, stress tends to concentrate in the hole. Therefore, since the backwashing treatment cannot be performed with a very strong pressure, the effect of the pulse jet method, which is a high-performance cleaning mechanism, is not exhibited, and the application is limited to applications where the filtration speed is low or the load dust concentration is low. I will. In view of the above, an object of the present invention is to solve the above-described problem, and to prevent a displacement of a pair of opposed filter media, and to avoid a concentration of stress acting on the filter media, to provide a filter element having high strength and durability. To provide.

[0010]

SUMMARY OF THE INVENTION It is an object of the present invention to form an internal space with a pair of filter media facing each other, and use the internal space as a space after filtration to collect fine particles on the outer surface of the filter media. In the filter element configured as described above, a filter frame disposed on the outer peripheral edge of the filter medium,
A holding member disposed in the filter frame body and fixed to the filter frame body, and a pair of self-supporting filter materials having respective outer peripheral edges attached to upper and lower surfaces of the filter frame body,
A holding member attached to the periphery of the filter frame body to closely adhere and fix an outer peripheral edge of the filter medium to a side portion of the filter frame body, wherein the holding member has a shape corresponding to a cross-sectional shape of the filter medium. The filter element is provided so as to be engaged with an inner surface of the filter medium.

According to the above configuration, the holding member can formally engage with the pair of filter media and hold the filter media at a predetermined position. Therefore, it is possible to prevent the displacement of the filtration material due to the repetition of the filtration process and the back washing process, and to prevent the internal space of the filter element from being crushed. In addition, since the holding member is only in contact with the inner surface of the filter medium and does not use the joining means, stress concentration hardly occurs in the portion of the filter medium to be held by the holding member. Therefore, there is no possibility that the filter material is broken due to a crack at the joint, unlike the conventional filter element.

[0012] It is another object of the present invention to provide a filter medium, wherein a groove is formed in the filter medium so as to be recessed inward from the outer surface of the filter medium, thereby suppressing expansion of the filter medium in an outward direction during back washing. This is achieved by the filter element, wherein a member is provided so as to be fitted into the groove portion, and the expansion suppressing member is configured so as not to substantially protrude from the outer surface of the filter medium.

According to the above construction, the holding member is formally engaged with the pair of filter media to hold the filter media at a predetermined position, thereby preventing the internal space of the filter element from being crushed. Since the expansion suppressing member presses the top of the filter medium, it is possible to prevent the filter medium from expanding outward during the backwashing process. Further, it is preferable that the holding member is disposed so as to coincide with the mounting position of the expansion suppressing member. In this case, suction of air from the outside to the inside of the filter medium at the time of the filtering process or back washing process is performed. Obstruction of air blowing from the inside to the outside of the filter medium at the time can be minimized, and it is possible to prevent a reduction in efficiency of the filtration process and the backwashing process. Further, it is preferable that the filter material is made of a heat-resistant polyimide fiber which is formed by heating.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of a filter element according to the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is an overall perspective view of a filter element according to a first embodiment of the present invention. The filter element 1 includes a rectangular filter frame 2 for maintaining the rigidity of the filter element 1, a holding member 3 disposed in the filter frame 2, and a pair of filter materials 4 attached to upper and lower surfaces of the filter frame 2. 5
And pressing members 6, 7, 8 attached to the periphery of the filter frame 2 so as to cover the outer peripheral edges of the filtering media 4, 5.

The filtering members 4 and 5 have the same shape and are arranged to face each other. The filtering materials 4 and 5 are obtained by cutting a non-woven fabric or a woven fabric made of a high heat-resistant polyimide fiber into a rectangular shape and fixing it on a rectangular mold.
It was heated in the range of 0 ° C. and formed into a corrugated sheet. The filtering media 4 and 5 have some rigidity and self-supporting properties. Although the high heat-resistant polyimide fiber is not particularly specified, for example, it is desirable to manufacture it from a polyimide having a repeating unit represented by the following general formula.

[0016]

Embedded image

FIG. 2 shows the filter element 1 shown in FIG.
FIG. 3 is an exploded perspective view of FIG. The filter frame 2 is formed to be slightly smaller than the outer edges of the pair of filter media 4 and 5, and has a constant thickness so as to hold the filter media 4 and 5 at predetermined intervals. The holding member 3 is formed by bending a plate material, and has a cylindrical section 3a having a substantially hexagonal cross section.
Are connected to each other to have a cross-sectional shape corresponding to the cross-sectional shape of the filter media 4 and 5. Note that, in the present embodiment, the holding members 3 are arranged in two stages at a fixed interval.

FIG. 3 is a sectional view of a portion A in FIG. 1 and shows a portion where the filtering members 4 and 5 are held by the holding member 3. FIG. 4 is a sectional view of a portion B in FIG. 1 and shows a portion where the filtering members 4 and 5 are not held by the holding member 3. Outer peripheral edges 4 a and 5 a of the pair of filter media 4 and 5 folded back so as to wrap the bent pieces 10 and 10 of the filter frame 2 are brought into close contact with the side 2 b of the filter frame 2 by the pressing member 8. The pressing member 8 is attached to the filter frame 2 via screws (or rivets) 11. In addition, other outer peripheral edges of the filter media 4 and 5 except for the can body attachment portion are similarly attached to the side portion 2a and the upper portion 2c of the filter frame 2 by pressing members 6 and 7.

The holding member 3 is provided in the internal space along a pair of filtering materials 4 and 5, and has both ends 3b, 3b.
Are fixed to the left and right sides 2a, 2b of the filter frame 2 by rivets 9. Note that a heat-resistant sealant is applied between the filter frame 2 and the filter members 4 and 5 and between the filter members 4 and 5 and the holding members 6, 7 and 8, and the filter element 1 is formed.
Can be further improved in sealing performance.

That is, in the filter element 1 according to the present embodiment configured as described above, the holding member 3 is formally engaged with the pair of filter media 4 and 5, and the filter media 4 and 5 are positioned at predetermined positions. Can be held. Therefore, it is possible to prevent the displacement of the filter media 4 and 5 due to the repetition of the filtering process and the back washing process, and to prevent the internal space of the filter element 1 from being crushed.

Further, since the holding member 3 is only in contact with the inner surfaces of the filtering media 4 and 5, and no joining means is used,
Stress concentration is unlikely to occur in the portions where the filtering materials 4 and 5 are held by the holding member 3. Therefore, there is no possibility that the filter members 4 and 5 are broken due to cracks at the joints unlike the conventional filter element 50. In the present embodiment, the filtering materials 4 and 5 having a certain degree of rigidity and having self-supporting properties have been described. However, the present invention is not limited to this, and it is also possible to apply to filtering materials without self-supporting properties.

FIG. 5 is a partially enlarged view showing a first modification of the holding member in the filter element 1. As shown in FIG. FIG.
The holding member 15 shown in FIG.
The plate material forming 5a has an opening, and the peripheral surface of each cylindrical segment 15a has a plurality of holes 15b. Thereby, the holding member 15 does not hinder the suction of air from the outside to the inside of the filter media 4 and 5 at the time of the filtration process and the blowing of air from the inside to the outside of the filter media 4 and 5 at the time of the backwash process. . Therefore, it is possible to prevent the efficiency of the filtering process and the back washing process from decreasing.

FIG. 6 is a partially enlarged view showing a second modification of the holding member in the filter element 1. As shown in FIG. Each of the filter media 4 and 5 has a corrugated cross-sectional shape in which the concave ridges 16a and the convex ridges 16b are formed alternately and continuously, and the outside of the concave ridges 16a and the inside of the convex ridges 16b. Are provided along the rod-shaped holding members 17, respectively.

That is, since both ends of the holding member 17 are fixed to the filter frame 2, each holding member 17 is formally engaged with the concave ridge 16a and the convex ridge 16b of the filter media 4 and 5. Thus, the filter media 4 and 5 can be held at predetermined positions. Therefore, the holding members 3 and 3 in the above embodiment are used.
Similarly to 15, the holding member 17 can prevent the filter members 4 and 5 from being displaced due to the repetition of the filtering process and the back washing process, and can prevent the internal space of the filter element 1 from being crushed.
Note that the holding member 17 may be attached to only one of the concave ridge 16a and the convex ridge 16b of the filter media 4 and 5.

FIG. 7 is an exploded perspective view of a filter element 20 according to a second embodiment of the present invention. The filter element 20 has a three-stage groove (only the upper filter material 27 is shown) 21 formed in each of the pair of filter materials 27 and 28 to suppress the filter materials 27 and 28 from expanding outward in the backwashing process. This is an element in which the expansion suppressing member 22 is fitted into each groove 21. The groove 21 is provided in the filter element 20.
It is desirable that the depth is such that the hollow portion is not closed, and that the expansion suppressing member 22 does not protrude from the outer surfaces of the filter media 27 and 28.

FIG. 8 shows the filter element 2 shown in FIG.
0 is an overall perspective view showing the expansion suppressing member 22 in each groove 21.
Shows a state in which it has been fitted into the. The expansion suppressing member 22 has both ends 22a and 22b fixed with screws 11 or the like, but may be attached by other attaching means. In addition, the expansion suppressing member 2
2 may be attached one on the diagonal line of the filter media 27 and 28, or two may be attached so as to cross each other.

FIG. 9 is a sectional view of a portion C in FIG.
7 and 8 show portions where the holding members 7 and 28 are held by the holding member 3. FIG.
Reference numeral 0 is a cross-sectional view of a portion D in FIG. 9 and illustrates a portion where the filtering members 27 and 28 are not held by the holding member 3. A pair of filter media 27, 2
Reference numeral 8 denotes an outer peripheral edge portion 27a, 28a folded back so as to wrap the bent pieces 10, 10 of the filter frame 2, and is pressed by the pressing member 8 so as to be in close contact with the side portion 2b of the filter frame 2. The holding member 8 is attached to the filter frame 2 via a screw (or rivet) 11.

The holding member 3 is provided in the internal space along a pair of filtering materials 27, 28, and has both ends 3b, 3b.
Are fixed to the left and right sides 2a, 2b of the filter frame 2 by rivets 9. In addition, the holding member 3 in the present embodiment is disposed so as to coincide with the mounting position of the expansion suppressing member 22, so that the filtering material 27,
Obstacles of suction of air from the outside to the inside of the filter 28 and blowing of air from the inside of the filter media 27 and 28 to the outside during the backwashing process are minimized, and the efficiency of the filtering process and the backwashing process is reduced. Drop can be prevented.

Therefore, in the filter element 20 according to the second embodiment, the holding member 3 has a pair of filtering materials 27 and 28.
By holding these filter members 27 and 28 in a predetermined position by formally engaging them, it is possible to prevent the internal space of the filter element 20 from being crushed and to prevent the expansion suppressing member 2 from being collapsed.
2 presses the tops of the filter media 27 and 28, thereby preventing the filter media 27 and 28 from expanding outward during the backwashing process.

Here, a specific manufacturing method of the filter element 20 will be described. First, a nonwoven fabric as a filtering material is manufactured. That is, benzophenone-3,3 ',
4,4'-tetracarboxylic dianhydride and 4,4'-
A polyimide fiber having a draw ratio of 1: 5 and a thickness of 30 μm is produced from methylene-bis- (tolylene isocyanate).
Next, a nonwoven fabric having a basis weight of 500 g and a thickness of 2 mm was preliminarily formed from the polyimide fiber by a needle punch method, and a width of 1500 mm and a length of 3000 mm was obtained from the preformed nonwoven fabric.
mm non-woven fabric. The chemical structural formula of the polyimide constituting the polyimide fiber is shown below.

[0031]

Embedded image

Next, the nonwoven fabric is formed into a corrugated shape using a mold. That is, the nonwoven fabric is fixed to the mold. This mold is provided with a parallel wavy shape on one side and three rectangular grooves shallower than the wavy shape in a direction perpendicular to the wavy shape. The mold has a length of 1500
It is made of steel or aluminum having a thickness of 1000 mm, a width of 1000 mm and a thickness of 50 mm. Further, the nonwoven fabric is fixed to the mold while a steel strip having the same shape as the cross-sectional shape of the groove is fitted into the groove of the mold from the outside of the nonwoven fabric. The mold has a flat portion having a width of 30 mm at the outer edge of the corrugated portion. When the nonwoven fabric is fixed to the mold, the nonwoven fabric is bent so as to form outer peripheral edges 4a and 5a (see FIG. 9) projecting from the three ends of the mold.

Next, the non-woven fabric is fixed to a mold for 34 days.
After heating at 0 ° C. for 2 hours and removing from the mold after cooling, a non-woven fabric of high heat-resistant polyimide having a self-supporting length of 150
The filter media 4 and 5 having a waveform of 0 mm × 1000 mm in width are obtained.
The filter media 4 and 5 having this waveform have shallow grooves 2 in a direction orthogonal to the waveform.
1 (see FIG. 7), and three extra sides of the filtering media 4 and 5 have extra outer peripheral portions 4a and 5a.

On the other hand, both ends of the holding member 3 formed by bending a steel plate having a thickness of 0.5 mm are fixed in the filter frame 2 with screws 11 or the like. The filter frame 2 is made of channel steel and a steel flat bar with a length of 1500 mm and a width of 1000 m.
m. Two holding members 3 are arranged evenly with respect to the length of the filter frame 2 of 1500 mm.

Next, the two filter media 4 and 5 are covered so as to cover the filter frame 2 from above and below. At this time, the protruding outer peripheral edges 4a, 5a of the three sides of the filter media 4, 5 cover the folded pieces 10, 10 (see FIG. 9) of the filter frame 2 so as to wrap them, and further press the outside thereof. 8 and fix with screws 11. At this time, a sealant may be applied between the filter frame 2 and the filtering materials 4 and 5.

Further, an expansion suppressing member 22 having the same cross-sectional shape as that of the groove and having a thickness of 1.6 mm and a length of 950 mm is fitted into a shallow groove perpendicular to the waveform of the filter media 4 and 5. 2 is fixed with a screw 11. Thus, the filter element 20 (see FIG. 8) is completed. Subsequently, at the open end of the filter element 20, a mounting member for installing a can body is installed from above the filter media 4 and 5, and fixed to the filter frame 2 with screws or the like, and the filter element 20 is attached to the can body. .

FIG. 11 is an overall perspective view of a filter element 25 according to a third embodiment of the present invention. The filter element 25 includes a holding member 26 that can suppress the pair of filtering materials 4 and 5 from expanding outward. The holding member 26 has a wavy cross section corresponding to the cross sectional shape of the filtering materials 4 and 5. It is configured to have a shape. These holding members 26 are provided along the outer surfaces of the filter media 4 and 5, and both ends are fixed to the filter frame 2 by screws 11 or the like.

FIG. 12 is a sectional view of a portion E in FIG. 11, and shows a portion where the filtering materials 4 and 5 are held by the holding members 3 and 26. FIG. 13 is a cross-sectional view of a portion F in FIG. 11 and shows a portion where the filtering media 4 and 5 are held only by the holding member 26. Since the pair of filter members 4 and 5 are sandwiched between the holding member 26 and the holding member 3, the displacement of the filter members 4 and 5 is more efficiently performed than when only the inside of the filter members 4 and 5 is held by the holding member 3. Can be prevented. Further, the holding member 26 presses the outer surfaces of the filtering materials 4 and 5, thereby preventing the filtering materials 4 and 5 from expanding outward during the backwashing process.

In the third embodiment, the filtering members 4 and 5 are sandwiched between the holding member 26 and the holding member 3.
The holding member 26 having the effect of suppressing the expansion of the filter media 4 and 5
When only the filter media 4 and 5 are provided along the outer surface,
The holding member 26 can prevent the filter members 4 and 5 from being displaced and crushing the internal space, and can also prevent the filter members 4 and 5 from expanding outward during the back washing process.

FIG. 14 is an overall perspective view of a filter element 30 according to a fourth embodiment of the present invention. The filter element 30 does not have the rigidity of the filter element in the filter frame 2 as in the first to third embodiments, and the flat ends 36 on the three sides of the upper and lower filter media 31 and 32 are sutured. Element 33 sewn. As the joining means, there are adhesion and fusion in addition to stitching.

The filter element 30 has a holding member 34 between the pair of filtering materials 31 and 32. The holding member 34 has substantially the same configuration as the holding member 3 of the first to third embodiments, except that both ends are not attached to the filter frame 2.

FIG. 15 is an overall perspective view of the holding member 34 shown in FIG. The holding member 34 includes a pair of filtering materials 31,
The holding members 34 are provided in two stages, and are connected to each other by connecting rods 35. Thus, it is possible to prevent the holding members 34, 34 provided in the two stages from being shifted from each other to increase or decrease the interval therebetween. When the filter element 30 is attached to a can (not shown), the can body holding means (not shown) holds the filter element 30 at a position corresponding to the holding members 34, 34.

Therefore, the holding members 34, 34 are held in a suitable position, and the filtering material 3
The displacement between 1 and 32 can be efficiently prevented. Note that the filter element of the present invention is not limited to the configuration of each of the above-described embodiments, but may take various forms.

[0044]

As is apparent from the above description, according to the filter element of the present invention, since the holding member corresponding to the cross-sectional shape of the filter is provided along the filter, the holding member is provided. The filter media can be formally engaged to hold the filter media in place. Further, since the holding member is only in contact with the filter medium, stress concentration hardly occurs on the portion to be held by the filter medium. Therefore, it is possible to provide a filter element having high strength and durability while preventing displacement of a pair of opposed filter media and avoiding stress concentration acting on the filter media.

[Brief description of the drawings]

FIG. 1 is an overall perspective view of a filter element according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of the filter element shown in FIG.

FIG. 3 is a sectional view of a portion A in FIG. 1;

FIG. 4 is a sectional view of a portion B in FIG. 1;

FIG. 5 is a partially enlarged view showing a first modification of the holding member in the filter element shown in FIG.

FIG. 6 is a partially enlarged view showing a second modification of the holding member in the filter element shown in FIG.

FIG. 7 is an exploded perspective view of a filter element according to a second embodiment of the present invention.

8 is an overall perspective view of the filter element shown in FIG.

FIG. 9 is a sectional view of a part C in FIG. 8;

FIG. 10 is a sectional view of a D part in FIG. 8;

FIG. 11 is an overall perspective view of a filter element according to a third embodiment of the present invention.

FIG. 12 is a sectional view of a portion E in FIG. 11;

FIG. 13 is a cross-sectional view of a portion F in FIG. 11;

FIG. 14 is an overall perspective view of a filter element according to a fourth embodiment of the present invention.

15 is an overall perspective view of a holding member in the filter element shown in FIG.

FIG. 16 is an overall perspective view of a conventional filter element.

FIG. 17 is a sectional view of a G part in FIG. 16;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Filter element 2 Filter frame 3 Holding member 4,5 Filtering material 6,7,8 Holding member

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B01D 46/02 B01D 46/52

Claims (4)

(57) [Claims] 1. A filter element configured to form an internal space with a pair of filter media facing each other, and to collect fine particles on an outer surface of the filter media using the internal space as a space after filtration, A filter frame disposed on the outer peripheral edge of the material, a holding member disposed in the filter frame and fixed to the filter frame, and a pair of outer peripheral edges attached to upper and lower surfaces of the filter frame, respectively. A self-supporting filter material, and a pressing member attached to the periphery of the filter frame body to closely adhere and fix an outer peripheral edge of the filter material to a side portion of the filter frame body, wherein the holding member includes the filter material. A filter element having a shape corresponding to the cross-sectional shape of the filter member, and being provided so as to be engaged with an inner surface of the filter medium. 2. The filter medium has a groove recessed inward of the element from the outer surface of the filter medium, and an expansion suppressing member for suppressing the expansion of the filter medium in an outward direction during the back washing process is fitted into the groove. The filter element according to claim 1, wherein the filter element is provided so that the expansion suppressing member does not substantially protrude from the outer surface of the filter medium. 3. The filter element according to claim 2, wherein the holding member is disposed so as to coincide with a mounting position of the expansion suppressing member. 4. The filter element according to claim 1, wherein the filter medium is formed by heat-molding a high heat-resistant polyimide fiber.