JP2011206724A - Filter element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a new filter element with protrusions abutting on each other, the protrusions formed on respective wall faces with pleat-likely formed sheet filter media facing with each other, having no problems of causing irregular spaces between the filter media due to displacement of crests of the protrusions, lowering of the effective filtering area due to great lowering of ventilation at abutting parts of the crests, and shortening of the filtering life due to the rise of the pressure loss.SOLUTION: In the filter element 10, pleats are formed on the sheet-like filter medium 11 containing thermoplastic fiber; the protrusions 21, 31 are provided on respective wall faces 20, 30 facing between the crest lines 12 and trough lines 13 of the pleats; and a tip end Ea (22) of one protrusion A (21) contacts a tip end Eb (32) of the other protrusion B (31), the area of the tip end Ea (22) being larger than the area of the tip end Eb (32).

Description

  The present invention relates to a filter element formed with pleats that is used by being mounted on an air conditioner in a building air conditioner, a factory air conditioner, a hospital air conditioner, or the like.

  For air conditioning equipment in building air conditioning, factory air conditioning, hospital air conditioning, and the like, a filter element in which a sheet-like filter medium is bent to increase its surface area is used to remove dust.

  As such a filter element, for example, in Patent Document 1, after a resin is applied linearly on both sides of a belt-like filter paper with a certain thickness, the belt-like filter paper is folded in a zigzag shape, and the opposing resins are joined together. A filter pack is disclosed in which the interval between the filter papers is kept constant by solidifying. However, such a filter element has a problem that the cost increases due to the cost of the raw materials for the resin, the equipment cost and the process cost due to the coating process in addition to the cost of folding in a zigzag manner. In addition, since the portion where the resin is applied is not air permeable, there is a problem that the pressure loss increases correspondingly and the filtration life is shortened. In addition, harmful volatile gas for the human body and goods is generated from the resin and pollutes the air environment, so that there is a problem of harming health or a problem of adversely affecting goods for electronic devices handled in a clean room. there were.

  Therefore, it has been proposed to keep the interval between the filter media constant by embossing without using a resin. As such a filter element, for example, in Patent Document 2, a protruding portion is formed on an adjacent folding wall facing a V-shape of a filter medium web folded in a zigzag shape, and the protruding portions are in contact with each other. A filter medium is disclosed. Further, FIG. 9 shows that the cross-section of this protrusion is semicircular, and the opposing protrusions abut against each other with the semicircular vertices abutting each other. However, when such embossed peaks contact linearly, there is a problem that the positions of the peaks are shifted and the interval between the filter media cannot be kept constant. In addition, if the same shape of the crests are in contact with each other with a surface having a certain width, the air permeability of that portion is remarkably lowered and the effective filtration area is lowered, so that the pressure loss is increased and the filtration life is shortened. There was a problem.

Japanese Patent Publication No.54-30144 JP-A-9-220427

  The present invention solves the above-mentioned problem and forms a sheet-shaped filter medium by pleating, so that the filter area is remarkably increased, and the projecting portions provided on the respective wall surfaces of the sheet-shaped filter medium are in contact with each other. In this case, there is no problem that the position of the peaks of the protruding portion is shifted and the interval between the filter media cannot be kept constant, and the air permeability of the contact portion between the peaks is remarkably lowered and the effective filtration area is lowered. It is an object of the present invention to provide a novel filter element that does not cause the problem that the pressure loss increases and the filtration life is shortened.

  In order to solve the above-mentioned problem, in the invention according to claim 1, pleats are formed on a sheet-like filter medium containing thermoplastic fibers, and projecting portions are formed on respective wall surfaces facing each other between a ridge line and a valley line of the pleat. The tip Ea of one protrusion A and the tip Eb of the other protrusion B are in contact with each other, and the area of the tip Ea is larger than the area of the tip Eb. The filter element was used as the solution.

  In the filter element according to the present invention, the filtration area is remarkably increased by pleating the sheet-shaped filter medium, and the protrusions provided on the respective wall surfaces facing each other in the sheet-shaped filter medium are in contact with each other. There is no problem that it becomes impossible to keep the interval of the filter medium constant by shifting the position of the filter, and the air permeability of the contact portion between the peaks is remarkably reduced, the effective filtration area is reduced, and the pressure loss is increased. It has become possible to provide a novel filter element that does not cause the problem of shortening the filter life.

It is a figure which shows an example of the filter element of this invention, and its manufacture process. It is a figure which shows another example of the filter element of this invention, and its manufacture process. It is the elements on larger scale of an example of the filter element of the present invention. It is the elements on larger scale of another example of the filter element of this invention. It is the elements on larger scale of another example of the filter element of this invention. It is a figure which shows an example of the protrusion part of the filter element of this invention. (A) is a plan view, and (b) is an elevation view thereof. It is a figure which shows another example of the protrusion part of the filter element of this invention. (A) is a plan view, and (b) is an elevation view thereof. It is a figure which shows another example of the protrusion part of the filter element of this invention. (A) is a plan view, and (b) is an elevation view thereof. It is a figure which shows another example of the protrusion part of the filter element of this invention. (A) is a plan view, and (b) is an elevation view thereof. It is a figure which shows another example of the protrusion part of the filter element of this invention. (A) is a plan view, and (b) is an elevation view thereof. It is a figure which shows another example of the protrusion part of the filter element of this invention. (A) is a plan view, and (b) is an elevation view thereof. It is a figure which shows another example of the protrusion part of the filter element of this invention. (A) is a plan view, and (b) is an elevation view thereof. It is a figure which shows another example of the protrusion part of the filter element of this invention. (A) is a plan view, and (b) is an elevation view thereof. It is a figure which shows another example of the protrusion part of the filter element of this invention. (A) is a plan view, and (b) is an elevation view thereof. It is a figure which shows another example of the protrusion part of the filter element of this invention. (A) is a plan view, and (b) is an elevation view thereof. It is a figure which illustrates typically the process in which a sheet-like filter medium is bent, a pleat is formed, and the example of the filter element of this invention is manufactured, and the cross-sectional shape after pleat formation. (A) is a figure which shows the sheet-like filter medium before forming a pleat. (B) is a figure which shows the longitudinal cross-section of (a). (C) is a figure which shows the state in the middle of pleat formation. (D) is the schematic diagram after further folding (c) and forming pleats. (E) is a figure which shows the cross section in the C-C 'line | wire of (d). (F) is the figure which further crushed the filter element of the state of (e), and made the wall surfaces approach. It is a figure which illustrates typically the process which bends a sheet-like filter medium, forms pleats, manufactures another example of the filter element of the present invention, and the section shape after pleat formation. (A) is a figure which shows the sheet-like filter medium before forming a pleat. (B) is a figure which shows the longitudinal cross-section of (a). (C) is a figure which shows the state in the middle of pleat formation. (D) is the schematic diagram after further folding (c) and forming pleats. (E) is a figure which shows the cross section in the C-C 'line | wire of (d). (F) is the figure which further crushed the filter element of the state of (e), and made the wall surfaces approach. It is a front view of the filter unit which consists of a filter element of the present invention. It is a rear view of the filter unit which consists of a filter element of the present invention. It is a front view of the filter unit which consists of a filter element of the present invention. It is a perspective view of the filter unit which consists of a filter element of the present invention.

  Hereinafter, embodiments of the filter element according to the present invention will be described in detail.

  As illustrated in FIGS. 1 to 5, the filter element 10 of the present invention has pleats formed on a sheet-like filter medium 11 containing thermoplastic fibers, and the pleats between a ridge line 12 and a valley line 13. Protruding portions 21 and 31 are provided on the respective wall surfaces 20 and 30 facing each other, and the leading end Ea (22) of one protruding portion A (21) and the leading end Eb (32) of the other protruding portion B (31). Are in contact with each other, and the area of the tip Ea (22) is larger than the area of the tip Eb (32).

  1 to 5, the shape of the bottom surface of the protruding portion A (21) or B (31) is a rectangle, but in the present invention, the shape of the bottom surface of the protruding portion is not particularly limited, and is polygonal or elliptical. Shapes, circles and any other shape can be applied. Also, in the explanatory view of FIG. 1 or FIG. 2, the sheet-like filter medium 11 is bent along the pleat mountain line 12 and the valley line 13 from the left hand to the right hand, and the protruding parts come into contact with each other to form the filter element 10. It shows how it is formed. In the present invention, the distance between the pleat mountain line 12 and the valley line 13 is preferably 50 to 500 mm, more preferably 70 to 280 mm, and still more preferably 100 to 180 mm. If it is less than 50 mm, the necessity of providing a separator may be reduced, and the processing cost for providing a protrusion may be expensive. Moreover, when it exceeds 500 mm, it may become impossible to maintain the distance between the peaks with high accuracy.

  The protrusions can be formed by embossing a sheet-like filter medium containing thermoplastic fibers. Further, it is possible to make a crease easily by making a line in a portion of the pleat which becomes a peak and a valley during the embossing. This embossing can employ a method in which a sheet-like filter medium is passed between a pair of heated forming rolls that have irregularities and the irregularities mesh with each other, and pressurizes. Alternatively, it is possible to employ a method in which a heated sheet-shaped filter medium is passed between a pair of coolable forming rolls and pressurized while cooling. In the case of embossing, the height of the tip end portions Ea (22) and Eb (32) of the protrusion is preferably 1 to 7 mm, and more preferably 2 to 7 mm. This height is also related to the cross-sectional shape of the protrusion. When the cross section is trapezoidal, the height is preferably 1 to 5 mm, and when the cross section is triangular or semicircular, it is 2 to 7 mm. preferable. When the cross section is triangular or semicircular, the filter medium can be sufficiently stretched by embossing compared to the trapezoidal shape, so that the height can be made higher than that of the trapezoidal shape.

  FIG. 3 is a partially enlarged view of the filter element 10 of FIG. FIG. 6 shows a state before the filter element of FIG. 1 is bent. In the example of FIGS. 3 and 6, the wall surface 20 has a trapezoidal cross-sectional protrusion A (21) having a long side 23 and short sides 24, 25 on the bottom surface, and the longitudinal direction of the sheet-like filter medium (or the pleat formation direction). It is arranged so as to have a long side 23 parallel to. Moreover, this protrusion part A (21) has the rectangular front-end | tip part Ea (22) which consists of a long side and the short sides 26 and 27, and is located in the mountain line 12 side of this front-end | tip part Ea (22). A mountain line side slope 28 connecting the short side 26 and the short side 24 of the bottom surface is formed. In addition, a valley-side slope 29 connecting the short side 27 located on the valley line 13 side of the tip end portion Ea (22) and the short side 25 of the bottom surface is formed.

The length of the projecting portion A of the bottom surface of the long side 23, depending on the spacing _{L PV} pleats mountain lines 12 and valley 13, is preferably 10~90mm less dimension than the spacing _{L PV,} 20 More preferably, the dimension is less by -50 mm. If it is less than 10 mm, pleat formation may be difficult, and if it exceeds 90 mm, the effect of the separator may be reduced. Moreover, it is preferable that both the short sides 24 and 25 of a bottom face are 3-20 mm, It is more preferable that it is 5-15 mm, It is still more preferable that it is 7-13 mm. If it is less than 3 mm, the height of the protruding portion may not be sufficiently secured, and if it exceeds 20 mm, the gas passage resistance may be too large.

  Further, the length of the long side of the rectangular front end portion Ea (22) is smaller than the length of the long side 23 of the bottom surface, but the height of the projecting portion and the mountain line side slope 28 and the valley line side slope 29 Can be determined according to the angle. Moreover, the length of the short side 27 of the rectangular front-end | tip part Ea (22) is less than the length of the short side 25 of a bottom face. The angle of the mountain line side slope 28 with respect to the bottom surface is preferably 3 to 90 °, and more preferably 5 to 80 °. If it is less than 3 °, the length of the long side of the tip Ea (22) may not be sufficiently secured, and if it exceeds 90 °, molding by embossing may be difficult. Moreover, it is preferable that the angle with respect to the bottom face of the said valley side slope 29 is 30-90 degrees, and when it is less than 30 degrees, the length of the long side of the front-end | tip part Ea (22) may not fully be secured. Yes, if it exceeds 90 °, molding by embossing may be difficult.

  In the example of FIG. 6, a small second protrusion SA that is smaller in width and lower in height than the protrusion A (21) is formed on the mountain line-side slope 28 and the valley line-side slope 29. . The protrusion SA has a semicircular cross section, and when the pleats are formed, the sheet-shaped filter medium portion between the protrusion A (21) and the mountain line 12 or the valley line 13 is reinforced, and the mountain line side The effect of reinforcing the slope 28 and the valley-side slope 29 is achieved. In particular, when the sheet-like filter medium is a highly flexible material made of synthetic fibers, these effects become remarkable, and therefore it is desirable to provide the protruding portion SA. The width of the projecting portion SA is smaller than the length of the short sides 24 and 25 of the bottom surface of the projecting portion A (21), and is in the range of 1/2 to 1/20 of the length of the short sides 24 and 25. It is preferable that it is in the range of 1/3 to 1/15. Moreover, it is preferable that it is 0.5-5 mm, It is more preferable that it is 0.7-3 mm, The above-mentioned effect becomes remarkable in these ranges.

  3 and 6, the wall surface 30 has a projecting portion B (having a triangular cross-section with a bottom surface consisting of a long side 33 and short sides 34 and 35 at a position corresponding to the projecting portion A (21). 31) is arranged so as to have a long side 33 parallel to the longitudinal direction of the sheet-like filter medium (or the pleat forming direction). Further, the projecting portion B (31) has a straight tip portion Eb (32). An end portion 36 of the tip portion Eb (32) located on the mountain line 12 side and a short side 34 of the bottom surface A mountain line side slope 38 is formed. Further, a valley-side slope 39 that connects the end portion 37 located on the valley line 13 side of the tip end portion Eb (32) and the short side 35 of the bottom surface is formed.

The length of the protrusion bottom surface of the long side 33 of the B, like the protrusion A of the above, depending on the spacing _{L PV} pleats mountain lines 12 and valley 13, 10～90Mm than the distance _{L PV} The dimension is preferably small, and more preferably 20 to 50 mm less. If it is less than 10 mm, pleat formation may be difficult, and if it exceeds 90 mm, the effect of the separator may be reduced. Moreover, it is preferable that both the short sides 34 and 35 of a bottom face are 3-20 mm, It is more preferable that it is 5-15 mm, It is still more preferable that it is 7-13 mm. If it is less than 3 mm, the height of the protruding portion may not be sufficiently secured, and if it exceeds 20 mm, the gas passage resistance may be too large.

  Further, the length of the triangular tip Eb (32) is smaller than the length of the long side 33 of the bottom surface as in the case of the protrusion A described above. It can be determined according to the angle of the slope 39 on the valley line side. The angle of the mountain line side slope 38 with respect to the bottom surface is preferably 3 to 90 °, and more preferably 5 to 80 °. If it is less than 3 °, the length of the long side of the tip Eb (32) may not be sufficiently secured, and if it exceeds 90 °, molding by embossing may be difficult. Moreover, it is preferable that the angle with respect to the bottom face of the said valley line side slope 39 is 30-90 degrees, and when it is less than 30 degrees, the length of the long side of the front-end | tip part Eb (32) may become unable to be ensured enough. Yes, if it exceeds 90 °, molding by embossing may be difficult.

  In the example of FIG. 6, a small second protrusion SB that is smaller in width and lower in height than the protrusion B (31) is formed on the mountain line side slope 38 and the valley line side slope 39. . This protrusion SB has a semicircular cross section like the protrusion SA described above, and a sheet-like filter medium between the protrusion B (31) and the mountain line 12 or valley line 13 when the pleats are formed. While reinforcing a part, there exists an effect which reinforces the mountain line side slope 38 and the valley line side slope 39. FIG. In particular, when the sheet-like filter medium is a highly flexible material made of synthetic fibers, these effects become remarkable, and therefore it is desirable to provide the protruding portion SB. The width of the protruding portion SB is smaller than the length of the short sides 34 and 35 of the bottom surface of the protruding portion B (31), and is in the range of 1/2 to 1/20 of the length of the short sides 34 and 35. It is preferable that it is in the range of 1/3 to 1/15. Moreover, it is preferable that it is 0.5-5 mm, It is more preferable that it is 0.7-3 mm, The above-mentioned effect becomes remarkable in these ranges.

  In the example of FIGS. 3 and 6, as described above, the tip Ea (22) of the protrusion A (21) has a rectangular shape composed of long sides and short sides 26 and 27, while the protrusion B ( Since the tip portion Eb (32) of 31) is linear, the area of the tip portion Ea (22) is larger than the area of the tip portion Eb (32). Therefore, when the pleats are formed and the tip Ea (22) of one projection A (21) and the tip Eb (32) of the other projection B (31) contact each other, the peaks of the projections There is no problem that it becomes impossible to keep the interval of the filter medium constant by shifting the position of the filter, and the air permeability of the contact portion between the peaks is remarkably reduced, the effective filtration area is reduced, and the pressure loss is increased. There is an effect that the problem that the filtration life is shortened does not occur. In the present invention, even if it is linear or dot-like, it is assumed that it has an area close to 0 as much as possible, and the areas of the tips are compared.

  In the example of FIGS. 3 and 6, the wall surface 20 has a trapezoidal cross-sectional protrusion A (21) whose bottom surface is composed of a long side 23 and short sides 24 and 25, and a long side 23 parallel to the longitudinal direction of the sheet-like filter medium. The protrusion A ′ (21 ′) having the same shape as that of the protrusion A (21) is arranged adjacent to the protrusion A (21 ′) so as to protrude on the back side of the sheet-like filter medium. And this protrusion A '(21') and protrusion A (21) are the point-symmetrical positions, and have the positional relationship which the front and back turn over. Similarly, the wall surface 30 has a projecting portion B (31) having a triangular cross section composed of a long side 33 and short sides 34, 35 on the bottom surface so as to have a long side 33 parallel to the longitudinal direction of the sheet-like filter medium. However, a protrusion B ′ (31 ′) having the same shape as the protrusion B (31) is disposed adjacent to the protrusion B (31) so as to protrude to the back side of the sheet-like filter medium. And this protrusion part B '(31') and protrusion part B (31) are the positions which are point-symmetrical, and have the positional relationship which the front and back turn over. Thus, when the pleats are formed, the protrusion A ′ (21 ′) and the protrusion B ′ (31 ′) come into contact with each other, and at this time, the tip Ea ′ of the protrusion A ′ (21 ′) ( 22 ′) is a rectangle composed of a long side and a short side, while the tip end portion Eb ′ (32 ′) of the protrusion B (31 ′) is linear, and therefore the tip end portion Ea ′ (22 The area of ') is larger than the area of the tip Eb' (32 ').

  In the example of FIGS. 3 and 6, the wall surface 20 has a trapezoidal cross-sectional protrusion A (21) whose bottom surface is composed of a long side 23 and short sides 24 and 25, and a long side 23 parallel to the longitudinal direction of the sheet-like filter medium. However, it is also possible to arrange a plurality of similar trapezoidal protrusions A (21) in series, and in the example of FIGS. 21) are arranged in series. Thus, the effect which reduces ventilation resistance is anticipated by arrange | positioning several protrusion part A (21) in series. In addition, since the number of the valley line side slopes 28 and the mountain line side slopes 29 is increased, the effect of preventing the protrusion A from being crushed is obtained particularly when the sheet-like filter medium is a flexible material made of synthetic fibers. Be expected. 4 and 7, a protrusion SA is also provided between the two protrusions A (21), and this protrusion SA is the mountain-side slope 28 of one protrusion A (21). And the valley-side slope 29 of the other protrusion A (21). Further, the wall surface 30 is provided with a protruding portion B (31) having a triangular cross section whose bottom surface is composed of a long side 33 and short sides 34, 35 at a position corresponding to the protruding portion A (21). Two are arranged in series so as to have a long side 33 parallel to the direction (or the pleat forming direction), and a protrusion SB is also provided between the two protrusions B (31). Further, the protrusion A ′ (21 ′) and the protrusion B ′ (31 ′) similar to the protrusion A (21) and the protrusion B (31) are provided so as to protrude to the back side of the sheet-like filter medium. ing.

  In the present invention, the length of the short side of the bottom surface of the protrusion A (21) and the length of the short side of the bottom surface of the protrusion B (31) can be the same or different. The lengths of the short sides 34 and 35 on the bottom surface of the protrusion B (31) are larger than the lengths of the short sides 24 and 25 on the bottom surface of the protrusion A (21). In the present invention, the length of the long side of the tip end portion Ea (22) of the protruding portion A (21) and the length of the long side of the tip end portion Eb (32) of the protruding portion B (31) may be the same. In FIG. 4, the length of the straight tip portion Eb (32) is longer than the length of the long side of the tip portion Ea (22). As described above, the length of the tip portion Eb (32) having a small area or the length of the long side of the tip portion Eb (32) having a small area is longer than the length of the long side of the tip portion Ea (22) having a large area. Is also advantageous in that the tip Eb (32) of the protrusion B (31), which is considered to have low ventilation resistance, can reliably contact the tip Ea (22).

  In the example shown in FIG.3 and FIG.6, the long side 23 parallel to the longitudinal direction of a sheet-like filter medium has the trapezoidal-section protrusion part A (21) which the bottom face consists of the long side 23 and the short sides 24 and 25 on the wall surface 20. Both the mountain-side slope 28 and the valley-side slope 29 of the protrusion A (21) are steep slopes having an angle of 30 ° or more with respect to the bottom surface, but one slope is 30 °. It is possible to have a gentle slope of less than. (Hereinafter, a slope having an angle with respect to the bottom surface of 30 ° or more may be referred to as a steep slope, and a slope having an angle with respect to the bottom surface of less than 30 ° may be referred to as a gentle slope. In the examples shown in FIGS. 2, 5 and 8, the valley-side slope 29 is a steep slope, but the mountain-side slope 28 is It is a gentle slope 28. The gentle slope 28 is a portion corresponding to a gas inlet, and has an effect of reducing gas passage resistance due to the gentle slope. On the other hand, if the steep slope 29 is a gentle slope whose bottom is close to the valley line 13, the gas passage volume is reduced and the passage resistance is increased, so that the passage resistance is reduced. is doing.

  The angle of the gentle slope 28 with respect to the bottom surface is preferably 3 to 15 °, and more preferably 3 to 10 °. If it is less than 3 °, the length of the long side of the tip Ea (22) may not be sufficiently secured, and if it exceeds 15 °, the effect of reducing the gas passage resistance may be too small. Further, the angle of the steep slope 29 with respect to the bottom surface is preferably 30 to 90 °, and more preferably 40 to 80 °. If it is less than 30 °, the length of the long side of the tip Ea (22) may not be sufficiently secured, and if it exceeds 90 °, molding by embossing may be difficult.

  In the example of FIGS. 5 and 8, the wall surface 30 is provided with a projecting portion B (31) having a triangular cross section at a position corresponding to the projecting portion A (21). ) Is a steep slope, but the mountain line side slope 38 is a gentle slope 38. The gentle slope 38 is a portion corresponding to a gas inlet, and has the effect of reducing the gas passage resistance due to the gentle slope. On the other hand, if the steep slope 39 is a gentle slope whose bottom is close to the valley line 13, the gas passage volume is reduced and the passage resistance is increased. Therefore, the steep slope 39 has an effect of reducing the passage resistance. is doing.

  The angle of the gentle slope 38 with respect to the bottom surface is preferably 3 to 15 °, and more preferably 3 to 10 °. If it is less than 3 °, the length of the long side of the tip Eb (32) may not be sufficiently secured, and if it exceeds 15 °, the effect of reducing the gas passage resistance may be too small. Further, the angle of the steep slope 39 with respect to the bottom surface is preferably 30 to 90 °, and more preferably 40 to 80 °. If it is less than 30 °, the length of the long side of the tip Eb (32) may not be sufficiently secured, and if it exceeds 90 °, molding by embossing may be difficult.

  In the example of FIGS. 5 and 8, a small second protrusion SA having a smaller width and a lower height than the protrusion A (21) is formed only on the steep slope 29 side. A small second protrusion SB having a width smaller than that of the protrusion B (31) and lower than the protrusion B (31) is formed only on the steep slope 39 side. About the magnitude | size and effect of these protrusion part SA and protrusion part SB, it is as having demonstrated in the example of FIG.3 and FIG.6.

  In this invention, the form illustrated in FIGS. 9 to 15 can be adopted in addition to the forms shown in FIGS. Moreover, the form which combined these forms is employable.

  In the example of FIG. 9, the wall surface 20 has a trapezoidal cross-sectional protrusion A (121) similar to the cross-sectional trapezoidal protrusion A (21) shown in FIG. A protruding portion A ′ (121 ′) having a triangular section similar to the protruding portion B ′ (31 ′) having a triangular section is arranged. Further, the wall surface 30 is provided with a projecting portion B (131) having a triangular section similar to the projecting portion B (31) having a triangular section shown in FIG. A protrusion B ′ (131 ′) having a trapezoidal cross section similar to the protrusion A ′ (21 ′) of FIG.

  In the example of FIG. 10, the wall surface 20 is provided with a trapezoidal protrusion A (221) having the same shape and low height as the trapezoidal protrusion A (21) shown in FIG. Is provided with a trapezoidal protrusion A ′ (221 ′) having the same shape as that of the protrusion A ′ (21 ′) having a trapezoidal cross section shown in FIG. Further, the wall surface 30 is provided with a protruding section B (231) having the same shape and height as the protruding section B (31) having a triangular section shown in FIG. A protruding portion B ′ (231 ′) having the same shape and high height as that of the protruding portion B ′ (31 ′) having a triangular section is arranged. Further, the total value of the height of the protrusion A (221) and the height of the protrusion B (231) is equal to the height of the protrusion A ′ (221 ′) and the height of the protrusion B ′ (231 ′). The protrusions are arranged so as to be equal to the total value.

  In the example of FIG. 11, the wall surface 20 has a trapezoidal protrusion A (321) having a trapezoidal cross section composed of a short side 325 and a short side 324 with the bottom surface provided on the long side 323 and the valley line 13 (or the vicinity of the valley line 13). The long side 323 parallel to the longitudinal direction (or the pleat forming direction) of the sheet-like filter medium is arranged. The protrusion A (321) has a trapezoidal tip Ea (322) composed of a long side and short sides 326 and 325. The short side 326 of the tip Ea (322) and the short side of the bottom surface. A steep slope 328 (an angle with respect to the bottom surface of 30 ° or more) (or a mountain line side slope) connecting the side 324 is formed. The tip Ea (322) is also a gentle slope (the angle with respect to the bottom surface is less than 30 °) connecting the short side 326 and the short side 325 of the bottom surface. As for the size of the protrusion A (321) having a trapezoidal cross section, the dimensions described in the example of FIG. 6 or FIG. 8 can be applied to the same part as in the example of FIG. 6 or FIG.

  Further, the wall surface 30 includes a short side 335 and a short side 334 having bottom surfaces provided on the long side 333 and the valley line 13 (or in the vicinity of the valley line 13) at a position corresponding to the protruding portion A (321). The protruding section B (331) having a triangular cross section is arranged so as to have a long side 333 parallel to the longitudinal direction (or the pleat forming direction) of the sheet-like filter medium. The protrusion B (331) has a flat (triangular) tip Eb (332), and a steep slope connecting the end 336 of the tip Eb (332) and the short side 334 of the bottom. 338 (an angle with respect to the bottom surface of 30 ° or more) (or a slope on the mountain line side) is formed. The tip Eb (332) is also a gentle slope (an angle with respect to the bottom is less than 30 °) connecting the end 336 and the short side 335 of the bottom. Note that the dimensions described in the example of FIG. 6 or FIG. 8 can be applied to the same size as the example of FIG. 6 or FIG.

  In the example of FIG. 11, the protrusion A (321) having a trapezoidal cross section is disposed on the wall surface 20 so as to have a long side 323 parallel to the longitudinal direction of the sheet-like filter medium. ) And the protruding portion A ′ (321 ′) having the same shape as that in FIG. And this protrusion part A '(321') and protrusion part A (321) are the point-symmetrical positions, and are the positional relationship from which the front and back turned over. Similarly, a protrusion B (331) having a triangular cross section is arranged on the wall surface 30 so as to have a long side 333 parallel to the longitudinal direction of the sheet-like filter medium, and the protrusion B (331) is adjacent to the long side 333. The protrusion B ′ (331 ′) having the same shape is disposed so as to protrude to the back side of the sheet-like filter medium. And this protrusion part B '(331') and protrusion part B (331) are the point-symmetrical positions, and are the positional relationship from which the front and back turned over. Thus, when the pleats are formed, the protruding portion A ′ (321 ′) and the protruding portion B ′ (331 ′) are in contact with each other, and at this time, the tip end portion Ea ′ of the protruding portion A ′ (321 ′) ( 322 ′) is a trapezoid consisting of a long side and two short sides, while the tip Eb ′ (332 ′) of the protrusion B (331 ′) is planar (triangular), The area of the portion Ea ′ (322 ′) is larger than the area of the tip end portion Eb ′ (332 ′).

  In the example of FIG. 12, as in FIG. 11, the wall surface 20 has a trapezoidal cross section formed by a short side 425 and a short side 424 whose bottom surface is provided on the long side 423 and the valley line 13 (or in the vicinity of the valley line 13). The part A (421) is arranged so as to have a long side 423 parallel to the longitudinal direction (or the pleat forming direction) of the sheet-like filter medium. The protrusion A (421) has a trapezoidal tip Ea (422) composed of a long side 423 and short sides 426, 425, and the short side 426 of the tip Ea (422) and the bottom surface of the bottom Ea (422). A steep slope 428 (an angle with respect to the bottom surface of 30 ° or more) (or a mountain line side slope) connecting the short side 424 is formed. The tip Ea (422) is also a gentle slope (the angle with respect to the bottom surface is less than 30 °) connecting the short side 426 and the short side 425 of the bottom surface. For the size of the protrusion A (421) having a trapezoidal cross section, the dimensions described in the example of FIG. 6 or FIG. 11 can be applied to the same part as the example of FIG.

  Further, the wall surface 30 is provided with a projecting portion B (431) having a triangular cross section at a position corresponding to the projecting portion A (421). The bottom surface of the projecting portion B (431) is short with the long side 433. The end portion 443 of the long side 433 is provided on the valley line 13 (or in the vicinity of the valley line 13). Further, the protrusion B (431) has a linear tip Eb (432), and a steep oblique line 438 connecting the end 436 of the tip Eb (432) and the end 444 of the short side 434. (An angle with respect to the bottom surface is 30 ° or more) (or a diagonal line on the mountain line side) is formed. The tip Eb (432) is also a gentle oblique line (an angle with respect to the bottom is less than 30 °) connecting the end 436 and the end 443 of the long side 433. Note that the dimensions described in the example of FIG. 6 or FIG. 11 can be applied to the same size as the example of FIG. 6 or FIG.

  In the example of FIG. 12, the protrusion A (421) having a trapezoidal cross section is arranged on the wall surface 20 so as to have a long side 423 parallel to the longitudinal direction of the sheet-like filter medium, but next to the protrusion A (421). ) And the protruding portion A ′ (421 ′) having the same shape as that in FIG. And this protrusion part A '(421') and protrusion part A (421) are the point-symmetrical positions, and are the positional relationship from which the front and back turned over. Similarly, a protrusion B (431) having a triangular cross section is disposed on the wall surface 30, and a protrusion B ′ (431 ′) having the same shape as the protrusion B (431) is adjacent to the rear side of the sheet-like filter medium. It is arranged to protrude. And this protrusion B '(431') and protrusion B (431) are the point-symmetrical positions, and have the positional relationship which the front and back turn over. Thus, when the pleats are formed, the protrusion A ′ (421 ′) and the protrusion B ′ (431 ′) come into contact with each other, and at this time, the leading end Ea ′ of the protrusion A ′ (421 ′) ( 422 ′) is a trapezoid consisting of a long side and two short sides, while the tip Eb ′ (432 ′) of the protrusion B (431 ′) is linear, and therefore the tip Ea ′. The area of (422 ′) is larger than the area of the tip Eb ′ (432 ′).

  6-12, the rectangular or trapezoidal front-end | tip part Ea which the protrusion part A of a cross-sectional trapezoid has and the linear or triangular front-end | tip part Eb which the protrusion part B of a cross-sectional triangle has shown was shown. However, the cross-sectional shape of the projecting portion B is not limited to a triangle, and for example, as illustrated in FIG. 13, it is a trapezoid in which the area of the rectangular front end portion Eb is smaller than the area of the rectangular front end portion Ea. It is also possible, and it can also be semicircular as illustrated in FIG. In the case of a semicircular shape, the shape of the tip Eb is linear. Further, the shape of the tip end portion Eb of the protruding portion B is not necessarily limited to a linear or triangular shape. For example, as illustrated in FIG. 13, the area of the tip end portion Eb is smaller than the area of the rectangular tip end portion Ea. It can also be a rectangle with an area. Moreover, it is also possible to have a dot shape as illustrated in FIG. In FIG. 15, the protrusion B has a form in which a plurality of protrusions having a quadrangular pyramid shape are arranged in a line.

  16 and 17 are diagrams schematically illustrating a process of forming a pleat by bending a sheet-like filter medium and manufacturing a filter element of the present invention, and a cross-sectional shape after the pleat is formed. (A) In the figure, the sheet-like filter medium 11 before forming the pleats is formed with the protrusions A, protrusions A ′, protrusions B, and protrusions B in the same form as in FIGS. 4 and 7 or FIGS. 'Indicates a formed state. (B) The figure has shown the longitudinal cross-section of (a) figure, (c) The figure is the state in the middle of valley folding along the mountain line 12 along the mountain line 12 of the figure (a) figure, and the valley line 13 FIG.

  FIG. 4D is a schematic view after further folding of FIG. (D) According to the figure, the front-end | tip part Ea of the protrusion part A and the front-end | tip part Eb of the other protrusion part B are contacting linearly, and this linear contact part is the wall surface 20 and wall surface of the sheet-like filter medium 11 30 and the wall surface 20 and the wall surface 30 are parallel to each other. For this reason, the wall surface between a protrusion part and a mountain line and the wall surface between a protrusion part and a trough line are bent in the short side part of the bottom face of a protrusion part. In this invention, there exists an advantage that the filter element with the stable structure can be obtained by forming a pleat so that the wall surface 20 and the wall surface 30 may become parallel in this way. However, in the present invention, the wall surface 20 and the wall surface 30 are not limited to being parallel as in the pleats formed on the right side of FIGS. 1 and 2, and the tip end portion Ea of the protrusion A and the other protrusion B It is also possible to form a pleat so that the tip Eb of the pleat contacts in a dot shape. In this case, the folding angle of the pleat becomes larger. Further, in the case of the form of FIG. 11 or FIG. 12, the tip end Ea of the protruding portion A and the tip end Eb of the other protruding portion B are in contact with each other in a straight line shape or a flat shape. Although the contact portion is not parallel to the wall surface 20 and the wall surface 30 of the sheet-like filter medium 11, there is an advantage that a filter element having a stable structure can be obtained.

  (E) The figure is a figure which shows the cross section in the C-C 'line | wire of (d) figure. (E) From the figure, it can be seen that the filtration is performed when the gas in the I region passes through the sheet-like filter medium and reaches the O region in the hatched portion. FIG. 5F is a view in which the wall surface 20 and the wall surface 30 are brought closer to each other by further crushing the filter element in the state of FIG. (F) According to the figure, since the number of pleats can be increased, there is an advantage that an increase in filtration life can be obtained along with a decrease in pressure loss due to an increase in the filtration area of the sheet-like filter medium 11.

  In the case of the form illustrated in FIGS. 1 to 5, the preferred dimension of the filter element of the present invention is such that the height H of the filter element is preferably 50 to 500 mm, more preferably 70 to 280 mm, and 100 to More preferably, it is 180 mm. If it is less than 50 mm, the necessity of providing a separator may be reduced, and the processing cost for providing a protrusion may be expensive. Moreover, when it exceeds 500 mm, it may become impossible to maintain the distance between the peaks with high accuracy. Moreover, it is preferable that the width W of a filter element is 100-900 mm, and it is more preferable that it is 200-700 mm. If it is less than 100 mm, the intended filtration area may not be obtained, and if it exceeds 900 mm, the structure of the filter element may become unstable during ventilation. Moreover, it is preferable that the length L of a filter element is 100-900 mm, and it is more preferable that it is 200-700 mm. If it is less than 100 mm, the intended filtration area may not be obtained, and if it exceeds 900 mm, the structure of the filter element may become unstable during ventilation.

  In the present invention, as illustrated in FIGS. 18 to 21, the filter unit 50 can be manufactured by attaching the rigid frame 40 to the filter element 10, and the filter unit 50 can be arranged in a general air conditioning facility or the like. 18 is a front view of the filter unit 50 obtained by attaching the rigid frame 40 to the filter element 10 shown in FIG. 1 or FIG. 2, FIG. 19 is a rear view of the filter unit 50, and FIG. It is the front view which represented the back of 50 with the dotted line. FIG. 21 is a perspective view of the filter unit 50 obtained by attaching the rigid frame 40 to the filter element 10 of FIG.

As the practical dimensions of the case of disposing the filter element of the present invention generally air conditioning, a generic dimension of the filter unit fitted with a rigid frame to the filter element, the height H _U 610 mm × width W _U It is preferable that the dimension is such that one or a plurality of filter elements can be accommodated in 610 mm × depth D _U 150 mm.

  Next, a preferable embodiment of the sheet-shaped filter medium 11 that can be applied as the filter element of the present invention will be described. The sheet-like filter medium is not particularly limited as long as it is a gas-permeable material including thermoplastic fibers. For example, a fiber substrate such as a woven fabric, a knitted fabric, a net, or a non-woven fabric can be applied. Among these, a non-woven fabric is particularly preferable because it can efficiently use the total area of the fiber surface widely and has many small voids formed by the fibers.

  The nonwoven fabric (hereinafter referred to as the nonwoven fabric substrate) as the fiber substrate is not particularly limited, and the structure of the nonwoven fabric substrate is typically a fiber length of 15 to 100 mm and a crimp number of 5 to 30 / inch. Generally called a dry method, in which a fiber called a staple fiber is formed on a fiber web using a card machine or an air array device, and then the constituent fibers are bonded together using an adhesive fiber or an adhesive. There is a nonwoven fabric obtained by a manufacturing method. Note that a nonwoven fabric obtained by bonding constituent fibers using an adhesive fiber such as a composite fiber is a suitable material because it is a clean material that is friendly to the environment and has excellent thermoformability. In addition to the dry method, there is a nonwoven fabric obtained by a production method called a spun bond method, a melt blow method, a wet method or the like. Moreover, the nonwoven fabric which made the fiber web obtained by these manufacturing methods act on a needle | hook, a water flow, etc. and entangled a constituent fiber is also applicable.

In order to obtain a medium-high performance filter element, it is desirable that high dust collection efficiency can be obtained while maintaining a low pressure loss. That is, it is preferable to use a nonwoven fabric that has a high dust collection efficiency and can extend the filtration life. As such a nonwoven fabric, for example, ultrafine fibers having an average fiber diameter of 0.1 to 10 μm formed by a melt blow method and heat-fusible fibers made of short fibers having an average fiber diameter of 10 to 50 μm are mixed, Moreover, a nonwoven fabric in which constituent fibers are bonded by the heat-fusible fiber can be exemplified. With such a nonwoven fabric, it is possible to have a high dust collection efficiency with ultrafine fibers and a bulky structure with heat-fusible fibers made of short fibers, and as a result, a state in which low pressure loss is maintained. It is possible to obtain high dust collection efficiency. The filtration performance of the filter element in this case is evaluated by a colorimetric method in the test method specified in JIS B 9908 type 2, and when the dimension of the air inflow surface is 610 mm square, the test condition is an air volume of 56 m ^3. At the time of / min, the average particle collection rate can be 80 to 98%, and for medium performance, it can be 60 to 95%. Moreover, when the electret process is given to the said nonwoven fabric, it is possible to set it as 80% or more.

  As the fibers constituting the nonwoven fabric, for example, synthetic fibers such as polyester fibers, polyamide fibers, acrylic fibers, modacrylic fibers, polypropylene fibers, polyethylene fibers, and polyurethane fibers, which are thermoplastic fibers, can be used. In addition, these fibers and synthetic fibers such as polyclar fiber, polyvinylidene chloride fiber, polyvinyl chloride fiber and polyvinyl alcohol fiber, regenerated fibers such as rayon and viscose, semi-synthetic fibers such as acetate, carbon fibers, It can be used by mixing with inorganic fibers such as glass fibers.

  In addition, the constituent fibers are preferably composite fibers. Examples of combinations of resin components constituting the composite fibers include polypropylene / polyethylene, polyester / low-melting polyester, polypropylene / low-melting polypropylene, nylon 66 / nylon 6, nylon 6 / Low melting point nylon, polyester / nylon 6, nylon 6 / polyethylene, polyester / polypropylene, etc.

  In addition, when the low melting point resin component of the composite fiber has thermal adhesiveness, the web constituent fiber can be thermally bonded by the resin component during embossing. Thus, when the low melting point resin component of the composite fiber has thermal adhesiveness, the fiber form can be maintained by the high melting point resin component, so that there is an advantage that the strength is excellent.

  Examples of the present invention will be described below, but these are only suitable examples for facilitating the understanding of the present invention, and the present invention is not limited to the contents of these examples.

Example 1
Using a short fiber having a fiber diameter of 2.2 decitex (17 μm), which is a core-sheath type composite fiber having a polyethylene resin as a low melting point sheath and a polypropylene resin as a high melting point core as a core, A fiber web having an areal density of 100 g / m ² was formed. Next, the fibrous web is moved to a heating zone while being sandwiched between a pair of belts, and the constituent fibers are bonded by heat-fusible fibers, and a sheet-like filter medium having a surface density of 100 g / m ² and a thickness of 1 mm. Got.

Next, the sheet-like filter medium is passed through a pair of forming rolls having irregularities and the irregular parts mesh with each other, and the sheet-form filter medium is pressurized, so that FIG. Protrusions (A, A ′, B, B ′) shown were formed. In addition, the embossing is performed so as to facilitate the formation of a crease by making a crease in the ridges and valleys of the pleats.
The distance L _PV between the mountain line 12 and the valley line 13 of the obtained pleat is 130 mm, the height of the tip Ea (22) of the protrusion is 3.5 mm, and the height of Eb (32) is 5 mm. there were.
Moreover, the length of the long side 23 of the bottom face of the protrusion A (21) having a trapezoidal cross section was 33 mm, and the lengths of the short sides 24 and 25 were both 6.5 mm. The distance between the short side 24 on the bottom surface and the mountain line 12 was 27 mm, and the distance between the short side 25 on the bottom surface and the valley line 13 was 27 mm. Moreover, the long side length of the rectangular front-end | tip part Ea (22) was 29 mm, and the length of the short side 27 was 4 mm. Further, both the mountain line side slope 28 and the valley line side slope 29 of the protruding portion A were 60 ° with respect to the bottom surface, and were steep slopes. The distance between the two protrusions A was 10 mm from the short side 25 of the bottom surface of one protrusion A to the short side 26 of the bottom surface of the other protrusion A.
Moreover, the 2nd protrusion part SA is formed in the mountain line side slope 28 and the valley line side slope 29 of the protrusion part A, The width | variety of these protrusion part SA is 1 mm, length is 5 mm, and high The thickness was 1 mm, and the tip of the protrusion had a semicircular cross section. A similar second protrusion SA is also formed between the two protrusions A.
Moreover, protrusion part A '(21') of the same dimension as protrusion part A (21) was arrange | positioned so that it might protrude on the back side of a sheet-like filter medium. The protrusion A ′ and the protrusion A are in a point-symmetrical position and have a positional relationship in which the front and back are further turned over.
Further, the length of the long side 33 of the bottom surface of the projecting portion B (31) having a triangular cross section was 41 mm, and the lengths of the short sides 34 and 35 were both 8 mm. The distance between the short side 34 of the bottom surface and the mountain line 12 was 19 mm, and the distance between the short side 35 of the bottom surface and the valley line 13 was 19 mm. Moreover, the length of the linear front-end | tip part Eb (32) was 35 mm. In addition, the mountain line side slope 38 and the valley line side slope 39 of the protruding portion B are both steep slopes at an angle of 60 ° with respect to the bottom surface. The distance between the two protrusions B was 10 mm from the short side 36 of the bottom surface of one protrusion B to the short side 35 of the bottom surface of the other protrusion A.
Moreover, the 2nd protrusion part SB is formed in the mountain line side slope 38 and the valley line side slope 39 of the protrusion part B, These protrusion parts SB are 1 mm in width, 5 mm in length, The thickness was 1 mm, and the tip of the protrusion had a semicircular cross section. A similar second protrusion SB is also formed between the two protrusions B.
Further, the protrusion B ′ (31 ′) having the same dimensions as the protrusion B (31) is arranged so as to protrude to the back side of the sheet-like filter medium. In addition, this protrusion part B '(31') and protrusion part B (31) became the positional relationship in which the front and back turned over in the point symmetrical position.

Next, as shown in FIGS. 4 and 16, the filter element having the shape shown in FIGS. 16D and 16E is obtained by folding the mountain along the mountain line 12 and folding the valley along the valley line 13. It was.
In this filter element, the tip Ea (22) of the protrusion A (21) and the tip Eb (32) of the other protrusion B (31) are in linear contact with each other. The contact portion was parallel to the wall surface 20 and the wall surface 30 of the sheet-like filter medium 11, and at the same time, the wall surface 20 and the wall surface 30 were parallel. Moreover, the wall surface between a protrusion part and a mountain line and the wall surface between a protrusion part and a trough line were bent in the short side part of the bottom face of a protrusion part. Since the pleats are formed so that the wall surface 20 and the wall surface 30 are parallel to each other in this way, the obtained filter element has a stable structure. Further, the height H of this filter element was 130 mm, the width W was 590 mm, the length L was 590 mm, and 65 pleats were formed.
Next, a rigid frame was attached to the filter element to form a filter unit having a height H _U 610 mm × width W _U 610 mm × depth D _U 150 mm as shown in FIGS.

(Example 2)
As shown in FIG. 4 and FIG. 16, as shown in FIGS. 4 and 16, a mountain fold is performed along the mountain line 12, and a valley fold is performed along the valley line 13. An intermediate filter element was obtained. Next, the filter element intermediate body is crushed so as to be about 80% of the original thickness, and the filter element in which the wall surface 20 and the wall surface 30 are brought close to each other as shown in FIG. Obtained.
In this filter element, the tip Ea (22) of the protrusion A (21) and the tip Eb (32) of the other protrusion B (31) are in linear contact with each other. The contact portion was parallel to the wall surface 20 and the wall surface 30 of the sheet-like filter medium 11, and at the same time, the wall surface 20 and the wall surface 30 were parallel. Moreover, the wall surface between a protrusion part and a mountain line and the wall surface between a protrusion part and a trough line were bent in the short side part of the bottom face of a protrusion part. Since the pleats are formed so that the wall surface 20 and the wall surface 30 are parallel to each other in this way, the obtained filter element has a stable structure. Further, the height H of this filter element was 130 mm, the width W was 590 mm, the length L was 590 mm, and 80 pleats were formed.
Thus, since the number of pleats increased 1.2 times with respect to the number 65 of the pleats of the filter element of Example 1, the filtration area of the sheet-like filter medium 11 could be increased.
Next, a rigid frame was attached to the filter element to form a filter unit having a height H _U 610 mm × width W _U 610 mm × depth D _U 150 mm as shown in FIGS.

(Example 3)
In the same manner as in Example 1, a sheet-like filter medium having an areal density of 100 g / m ² and a thickness of 1 mm was obtained. Next, the sheet-like filter medium is passed through a pair of forming rolls having irregularities and the irregular parts mesh with each other, and the sheet-like filter medium is pressurized, whereby FIG. The protrusion part (A, A ', B, B') shown in 17 was formed. In addition, the embossing is performed so as to facilitate the formation of a crease by making a crease in the ridges and valleys of the pleats.
The distance L _PV between the mountain line 12 and the valley line 13 of the obtained pleat is 130 mm, the height of the tip Ea (22) of the protrusion is 3.5 mm, and the height of Eb (32) is 5 mm. there were.
The length of the long side 23 of the bottom surface of the protrusion A (21) having a trapezoidal cross section was 95 mm, and the lengths of the short sides 24 and 25 were both 10 mm. The distance between the short side 24 on the bottom surface and the mountain line 12 was 5 mm, and the distance between the short side 25 on the bottom surface and the valley line 13 was 30 mm. Moreover, the long side length of the rectangular front-end | tip part Ea (22) was 66 mm, and the length of the short side 27 was 7 mm. Further, the slope A on the mountain line side 28 of the protrusion A is a gentle slope with respect to the bottom surface, and the slope 29 on the valley line side of the protrusion A is 60 ° with respect to the bottom surface. It was.
Moreover, the 2nd protrusion part SA is formed in the valley side slope 29 of protrusion part A, The width | variety of this protrusion part SA is 1 mm, length is 5 mm, height is 1 mm, protrusion The tip of the part had a semicircular cross section.
Moreover, protrusion part A '(21') of the same dimension as protrusion part A (21) was arrange | positioned so that it might protrude on the back side of a sheet-like filter medium. The protrusion A ′ and the protrusion A are in a point-symmetrical position and have a positional relationship in which the front and back are further turned over.
Further, the length of the long side 33 of the bottom surface of the projecting portion B (31) having a triangular cross section was 95 mm, and the lengths of the short sides 34 and 35 were both 10 mm. The distance between the short side 34 on the bottom surface and the mountain line 12 was 5 mm, and the distance between the short side 35 on the bottom surface and the valley line 13 was 30 mm. Moreover, the length of the linear front-end | tip part Eb (32) was 65 mm. In addition, the mountain-side slope 38 of the protrusion B is a gentle slope with respect to the bottom surface of 12 °, and the valley-side slope 39 of the protrusion B is 60 ° with respect to the bottom surface and becomes a steep slope. It was.
Moreover, the 2nd protrusion part SB is formed in the valley side slope 39 of the protrusion part B, The width | variety of this protrusion part SB is 1 mm, length is 5 mm, height is 1 mm, protrusion The tip of the part had a semicircular cross section.
Further, the protrusion B ′ (31 ′) having the same dimensions as the protrusion B (31) is arranged so as to protrude to the back side of the sheet-like filter medium. The protrusion B ′ and the protrusion B are in a point-symmetrical position and have a positional relationship in which the front and back are further turned over.

Next, as shown in FIGS. 2, 5, and 17, the filter element having the shape shown in FIGS. 17D and 17E is formed by folding the mountain along the mountain line 12 and the valley along the valley line 13. Got.
In this filter element, the tip end portion Ea of the protruding portion A and the tip end portion Eb of the other protruding portion B are in linear contact, and the linear contact portion is the wall surface 20 and the wall surface of the sheet-like filter medium 11. 30 and the wall surface 20 and the wall surface 30 were parallel at the same time. Moreover, the wall surface between a protrusion part and a mountain line and the wall surface between a protrusion part and a trough line were bent in the short side part of the bottom face of a protrusion part. Since the pleats are formed so that the wall surface 20 and the wall surface 30 are parallel to each other in this way, the obtained filter element has a stable structure. Further, the height H of this filter element was 130 mm, the width W was 590 mm, the length L was 590 mm, and 65 pleats were formed.
Next, a rigid frame was attached to the filter element to form a filter unit having a height H _U 610 mm × width W _U 610 mm × depth D _U 150 mm as shown in FIGS.

Example 4
As in the third embodiment, as shown in FIGS. 2, 5, and 17, a mountain fold is performed along the mountain line 12 and a valley fold is performed along the valley line 13. A filter element intermediate having the shape shown in FIG. Next, the filter element intermediate body is crushed so as to be about 80% of the original thickness, and the filter element in which the wall surface 20 and the wall surface 30 are brought close to each other as shown in FIG. Obtained.
In this filter element, the tip end portion Ea of the protruding portion A and the tip end portion Eb of the other protruding portion B are in linear contact, and the linear contact portion is the wall surface 20 and the wall surface of the sheet-like filter medium 11. 30 and the wall surface 20 and the wall surface 30 were parallel at the same time. Moreover, the wall surface between a protrusion part and a mountain line and the wall surface between a protrusion part and a trough line were bent in the short side part of the bottom face of a protrusion part. Since the pleats are formed so that the wall surface 20 and the wall surface 30 are parallel to each other in this way, the obtained filter element has a stable structure. Further, the height H of this filter element was 130 mm, the width W was 590 mm, the length L was 590 mm, and 80 pleats were formed.
Thus, since the number of pleats was increased by a factor of 1.2 with respect to the number of pleats of the filter element of Example 1, the pressure loss was reduced due to an increase in the filtration area of the sheet-like filter medium 11. An increase in filtration life could be obtained.
Next, a rigid frame was attached to the filter element to form a filter unit having a height H _U 610 mm × width W _U 610 mm × depth D _U 150 mm as shown in FIGS.

DESCRIPTION OF SYMBOLS 10 Filter element 11 Sheet-like filter medium 12 Mountain line 13 Valley line 20 Wall surface 21,121,221,321,421 Projection part A
21 ', 121', 221 ', 321', 421 'Protrusion A'
22, 322, 422 End portion Ea of protrusion A
22 ′, 322 ′, 422 ′ The tip Ea ′ of the protrusion A ′
23, 323, 423 Long sides 24, 324, 424 of the bottom surface of the protruding portion A Short sides 25, 325, 425 of the bottom surface of the protruding portion A Short sides 26, 326, 426 of the bottom surface of the protruding portion A 27 Short side 28, 328, 428 of tip end portion Ea Mountain line side slope 29 of projection A A Valley line side slope 30 of projection A Wall surfaces 31, 131, 231, 331, 431 Projection B
31 ', 131', 231 ', 331', 431 'Projection B'
32, 332, 432 The tip Eb of the protrusion B
32 ′, 332 ′, 432 ′, tip portion Eb ′ of protrusion B ′
33, 433 Long side of the bottom surface of the projecting portion B: 443 Ends 34, 334, 434 of the long side 433 Short surface of the bottom surface of the projecting portion B: 444 End portions 35, 335 of the short side 434 Short of the bottom surface of the projecting portion B Side 36, 336, 436, end 37 of tip Eb end 38, 338 of tip Eb hillside slope of projection B: 438 Mountainline side oblique line of projection B, steep slope 39 Valley of projection B Line-side slope 40 Rigid frame 50 Filter unit A, A 'Protrusion B, B' Protrusion Ea Protrusion A tip Ea 'Protrusion A' tip Eb Protrusion B tip Eb 'Protrusion B' Tip part SA projecting part, second projecting part SB projecting part, second projecting part

Claims (1)

  Pleats are formed on a sheet-like filter medium containing thermoplastic fibers, and protrusions are provided on the respective wall surfaces facing each other between the ridge line and the valley line of the pleats, and the tip part Ea of one protrusion part A And the tip Eb of the other protrusion B are in contact with each other, and the area of the tip Ea is larger than the area of the tip Eb.

Images