JP2001293316A - Method for producing unit filter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a unit filter by determining the shape of pleats of a filter medium to obtain an optimum pressure loss for the filter without implementing a process in which a plurality of the filters are produced actually to measure the pressure losses of them in order to determine the shape of the pleats. SOLUTION: In a method for producing the unit filter in the shape of pleats, the shape of the pleats is determined by formula 1 (wherein, ΔP0 is the total pressure loss; ΔP* is the fluid resistance of the filter medium on a plate; ΔP1 is the shape resistance of the unit filter; σmax is the maximum tensile stress of the filter medium; ui is an average flow velocity at a unit inlet; ν is the dynamic viscosity of air; B* is the crest interval of pleats; t is the thickness of the filter medium; K is the resistance coefficient of the plate filter medium).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for manufacturing a unit filter, and more particularly to a method for manufacturing a unit filter in which a filter medium is bent and pleated.

[0002]

2. Description of the Related Art When manufacturing a filter, it is desired to reduce pressure loss. An important factor for the pressure loss of the unit filter is the structural resistance due to the pleated bending of the filter medium in addition to the resistance when air passes through the filter medium. The resistance of the air as it passes through the filter media can be determined relatively easily by measuring the pressure drop of the filter media, but the structural resistance can be determined by not actually fabricating a unit filter using the filter media. could not. For this reason, in order to manufacture a unit filter having a low pressure loss, a plurality of unit filters having different pleat heights and pleat crest intervals are manufactured, and the pressure loss is measured to select an optimum filter. Work was needed.

[0003]

[Problems to be solved by the invention]
As a result of various studies, it was found that such a structural resistance can be determined as a function of the structure of the unit filter, that is, the design conditions such as the pleat height, the interval between the pleated ridges and the thickness of the filter medium to be used, and the use conditions such as the processing air volume.
We succeeded in solving these problems.

[0004]

Means for Solving the Problems The present invention relates to a method of manufacturing a pleated unit filter, wherein the pleated shape is determined by the following equation (1).

(Equation 2) (Where △ P ₀ is the total pressure loss, △ P ^* is the fluid resistance in the flat plate of the filter medium, ΔP ₁ is the shape resistance of the unit filter,
sigma _max is the maximum tensile stress of the filter medium, u _i is the average velocity of the units entrance, [nu exercise viscosity of air, B ^* mountain spacing of the pleats, P is the pleat height, t is the filter media thickness, K is flat Resistance coefficient of filter media)

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION As the filter medium used in the present invention, any filter medium that can be processed into a pleated shape can be used. As the filter medium, for example, non-woven fabric,
Fabrics, knits, papers, nets, porous synthetic resin membranes, glass fiber sheets, deodorizing sheets, etc., or any combination thereof can be used. Filter media are particularly preferred. In addition, a filter medium on which an adsorbent such as activated carbon is supported can be used.

[0006] As the nonwoven fabric used for the filter medium, a dry nonwoven fabric, a wet nonwoven fabric, a melt-blown nonwoven fabric, a spunbonded nonwoven fabric, a hydroentangled nonwoven fabric and the like are suitable. The fibers constituting the nonwoven fabric may be any of short fibers, staple fibers, and filament fibers, or may be a mixture of these.

Examples of the fiber include polyamide, polyvinyl alcohol, polyvinylidene chloride, polyvinyl chloride, polyester, polyacrylonitrile, polyolefin such as polyethylene and polypropylene, polyurethane, glass, carbon, ceramic, and the like. Those containing one or more kinds of inorganic materials such as metals can be used. Further, two or more kinds of fibers may be mixed.

When such a nonwoven fabric is made of short fibers or staple fibers, for example, a fiber web is formed by a dry method or a wet method such as a card method or an air lay method, and when it is made of filament fibers, for example, a spunbond method is used. Or melt-blowing method to form a fiber web, then entangle these fiber webs with a water stream or a needle, fuse the constituent fibers in the fiber web, adhere with a binder, or use these together Can be formed.

The filter medium used in the present invention may be a single layer or a laminate of a plurality of layers. Further, the plurality of layers may be made of different materials or may be the same. When the nonwoven fabric is laminated, it is preferable that, for example, those having different densities, such as a dense layer and a coarse layer, and those having different properties, such as a dust removal layer and gas adsorption, are laminated.

[0010] The filter medium used in the present invention desirably includes a dense layer containing fine fibers having an average fiber diameter of 0.1 to 10 µm so that the collection efficiency is improved. In particular, the preferred average fiber diameter of the fine fibers is 0.3 to 8 μm. These fine fibers may be produced, for example, by a melt blow method, or may be generated from composite fibers such as splittable fibers and sea-island type fibers. The dense layer containing fine fibers may be composed of only fine fibers, or may be mixed with thicker fibers. The area density of the dense layer is 10 to 300 g / m.
It is preferably ² . If it is out of this range, dust collection efficiency or processing capacity may decrease,
More preferably, it is 15 to 80 g / m ² . When a dense layer is included, it is desirable that a layer coarser than this is laminated. By providing such a layer, the initial cleaning efficiency and the dust treatment capacity can be improved. Note that a porous resin film such as a Teflon (registered trademark) (PTFE) film may be laminated on the dense layer, or a glass fiber sheet may be used.

Further, the filter medium used in the present invention may be entirely or partially electretized.
If the filter medium is electret, dust can be collected by an electrostatic action, so that a unit filter with high collection efficiency can be easily manufactured with low pressure loss.

In the method of manufacturing a unit filter according to the present invention, the shape resistance ΔP ₁ of a unit filter made of filter materials of various materials is determined by the filter design conditions (P, B ^* , t, t).
K) and a pleat shape with an optimum total pressure loss is determined by using the equation (1) representing a function of the operating conditions (u _i , ν), and pleating is performed based on the pleat shape based on the pleat shape. Manufacture filters. For example, characteristics such as a resistance coefficient (K), a fluid resistance (ΔP ^* ), a thickness (t), and a maximum tensile stress (σ _max ) of the filter medium in a flat plate state, and a fluid to be treated which is an operation condition of the unit filter. The average flow velocity (u _i ) and the kinematic viscosity (ν) of air at the unit inlet side of the unit can be known from the measurement results and design conditions of the flat filter medium. By putting values such as (B ^* ) and pleat height (P) into equation (1), the total pressure loss (ΔP ₀ ) of the obtained unit filter can be obtained. Accordingly, a total pressure loss corresponding to a value specifying a plurality of pleat shapes is obtained, and a pleat shape of an optimum total pressure loss (usually, the one having the smallest pressure loss) is determined from the total pressure loss.
By pleating the filter medium in accordance with the design, it is possible to manufacture a unit filter having an optimum total pressure loss without actually manufacturing a plurality of unit filters and actually measuring the pressure loss thereof. Furthermore, by specifying the unknown, it is also possible to design the physical properties of the filter medium, the operation status of the unit filter, and the like.

In particular, among the values for specifying the pleat shape,
If either the pleated peak interval (B ^* ) or the pleat height (P) is determined, enter that value into equation (1) and prepare a plurality of other value candidates. Into the equation (1) to calculate the total pressure loss, determine the one with the smallest total pressure loss, and perform pleating based on the conditions to manufacture a unit filter with a low pressure loss. For example, when the external dimensions of the unit filter are determined and the pleat height is determined, the value of the pleat height and the value of the plurality of prepared pleat intervals are determined by the value obtained from the measurement of the filter medium in a flat state or the unit filter. By applying to equation (1) together with the value determined from the operating conditions of (1), the total pressure loss for each pleat interval can be determined. From this result, the pleat interval with the smallest total pressure loss may be determined. By pleating the filter medium based on the determined pleat spacing and pleat height, a unit filter with a small total pressure loss can be obtained. In addition,
When the optimum value of the total pressure loss of the unit filter is given in advance, the total pressure loss obtained by the equation (1) is equal to the pleat peak interval and the pleat height which are closest to the previously given optimal value. It is only necessary to determine the size and manufacture the unit filter.

The invention of this application relates to a method of manufacturing a unit filter characterized in that the pleat shape is determined by the equation (1) as described above. This equation (1) is as follows: Can understand its validity. FIG.
Shows a state in which a filter medium having a folded height P of V-shaped pleats, the number of pleats N, and the interval between pleats B ^* (= W / N) is set in a unit frame having a width W and a height H of an inlet. . The average flow velocity on the unit inlet side is u _i (= V / WH), and the static pressure difference before and after the unit filter at this flow velocity is defined as the total pressure loss ΔP ₀ of the unit filter. Chen et al. (199
According to 5), the following relationship exists between the total pressure loss ΔP ₀ due to the pure airflow of the unit filter and the fluid resistance ΔP ^* in the flat plate of the filter medium by the dimensional analysis method.

[Equation 3] Now, if (P >> t)

(Equation 4) Becomes Here, K is the resistance coefficient (1 / m) of the flat filter medium, t
Is the thickness (m) of the filter medium, P is the pleat height (m), and B ^* is the interval between the pleat peaks (m). FIG. 2 shows an actual measurement example of the total pressure loss ΔP ₀ of the unit filter when the air flow rate V and the pleat height P are kept constant and the peak interval B ^* is changed.
It can be seen that at a constant V and P, there is a minimum value of ΔP ₀ at a certain mountain interval B. As a result of experiments, this tendency can be seen even when the properties of V (or u _i ) and the filter medium are changed. Now, from the relationship of equation (3), the increase ｛(ΔP ₀ / △) of the resistance ΔP0 of the unit filter with respect to the resistance ΔP ^* of the clean filter medium.
P ^* ) − 1 is plotted on the ordinate of the logarithmic paper, and the measured values in FIG. 2 are stippled to obtain the results in FIG. As is clear from this figure, the increase in the pressure loss {(ΔP ₀ / {P ^* ) − 1} is the pleated dimensionless parameter {(8 / KP) (2P / B ^* ) ^.
−2t) ³ ), P = constant and has a linear relationship approximately proportional to 乗 power. Where the proportional coefficient k ₀ is

(Equation 5)And according to the experiment, k₀Is u_iAnd P
Inols number Rep = (ρ _fu_iP / μ) approximately 1/3 power
, And B^*And the ratio of P (B^*/ P) to the 1/3 power
Is proportional to Therefore, the shape characteristic value k for the filter medium₁
Is

(Equation 6) Becomes ν is the kinematic viscosity of air (= μ / ρ _f ). The maximum tensile stress σ _{max based} on the maximum tensile strength W _max [N] was determined by the following equation as the physical property value of the filter medium.

Equation 7 σ _max = W _max / bt (6) where b is the width of the sample used in the tensile test. 4 for sigma _max calculated from the above equation, summarizes by stippling the shape characteristic value k _l of unit filters consisting of filter media of various materials, the following equation.

(Equation 8) From the above results, the shape resistance ΔP ₁ of the unit filter is as follows.

(Equation 9) (Where △ P ₀ is the total pressure loss, △ P ^* is the fluid resistance in the flat plate of the filter medium, ΔP ₁ is the shape resistance of the unit filter,
sigma _max is the maximum tensile stress of the filter medium, u _i is the average velocity of the units entrance, [nu exercise viscosity of air, B ^* mountain spacing of the pleats, P is the pleat height, t is the filter media thickness, K is flat from resistance coefficient) the results of such filter medium, the shape resistance [Delta] P ₁ of unit filters made of various materials, the design conditions of the filter (P, B
^* , T, K) and operating conditions (u _i , ν) and can be determined by equation (1).

[0015]

The present invention will be specifically described below with reference to examples.

Example 1 Polyester fiber 5 having a fiber diameter of 10 μm and a fiber length of 51 mm
0 wt% and an acrylic resin 50 wt% and a surface density of 72 g / m ² made of a nonwoven fabric, a melt blown nonwoven fabric made of polypropylene fibers of fiber diameter of about 3~8μm stacked, thickness partially ultrasonic fusion A filter medium having a thickness (t) of 0.82 mm was obtained. The maximum tensile strength ( _Wmax ) of the filter medium at a sample width (b) of 5 cm was 150 N. The maximum tensile stress (σ _max ) of the filter medium is 3.66 × 10 ⁶ N / m ² from the relationship of σ _max = W _max / bt. The resistance coefficient (K) of the filter medium on a flat plate was 4.46 × 10 ⁶ (1 / m). On the other hand, the operating condition of the unit filter was such that the air volume (V) was 7.2 m ³ / min. Inlet height of the unit filter (H) is 0.2 m, the width (w) is the 0.2 m, the average flow velocity of the unit inlet side _{(u i)} is _u i = V / W
From the relationship of H, it is 3 m / s. The kinematic viscosity (ν) of the air was 1.51 × 10 ⁻⁵ m ² / s (20 ° C.). The resistance (ΔP ^* ) of the filter medium is defined as ΔP ^* = K ₁ × _uf , between the filter medium passage speed ( _uf ) of the fluid to be treated and the pressure loss (K ₁ ) of the filter medium at a wind speed of 1 m / s. There is a relationship of ^1.15 . Since the filter medium passage speed ( _uf ) can be obtained by dividing the air volume by the total filter medium area used in the unit, _uf = V /
2NPH = VB ^* / 2WPH (however, the number of pleats is N
= W / B ^* ), and can be obtained by substituting each value. Since K ₁ is a 93Pa by measuring the resistance of the filter medium from these ([Delta] P ^*) is obtained. Filter media passage speed (u
_f ) changes when the pleated peak interval (B ^* ) changes, and as a result, the resistance (ΔP ^* ) of the filter medium also changes depending on the pleated peak interval (B ^* ). When the pleat height (P) is 0.012 m among the pleat shapes of the unit filter, the interval between the pleat peaks (B ^* ) is 3 mm, 4 mm, and 5 mm.
mm, the total pressure loss of the unit filter (ΔP
₀ ) was obtained from the equation (1), and as shown in Table 1, the total pressure loss (ΔP ₀ ) at a pleat peak interval (B ^* ) of 4 mm was the lowest. Based on this result, the filter medium was pleated under the conditions of a pleated height of 0.012 m and a pleated interval of 4 mm to produce a unit filter. In addition, the filter medium was pleated under the conditions of 3 mm, 4 mm, and 5 mm of the pleat crest interval (B ^* ) to produce a unit filter.
The results of measuring the total pressure loss are shown in Table 1. According to the actual measurement results, the total pressure loss of the unit filter pleated under the condition of the pleat peak interval of 4 mm is the lowest among the manufactured unit filters, and the pleat shape having the pleat interval determined by the formula (1) is appropriate. I understand. The values of the design conditions and operating conditions of this unit filter are as follows: resistance of the filter medium (△ P ^* ) = K ₁ × _uf ^1.15 (K ₁ = 9
3 Pa, _uf = VB ^* / 2 WPH) Filter media thickness (t) = 0.82 mm = 0.00082 m Maximum tensile stress (σ _max ) of the filter media = 3.66 x 10 ⁶
Resistance coefficient (K) of a flat plate of N / m ² filter media = 4.46 × 10 ⁶ (1
/ M) Average flow velocity (u _i ) on the unit inlet side = 3 m / s Kinematic viscosity of air (ν) = 1.51 × 10 ^-5 m ² / s
(20 ° C.) The pleated height (P) is 0.012 m 2, and the pleated peak interval (B ^* ) and the total pressure loss (ΔP ₀ ) of the unit filter are as shown in Table 1.

[Table 1] Pleated peak interval B ^* (mm) ΔP ₀ calculation result (Pa) ΔP ₀ measurement result (Pa ) 398.5 58.4 86.8 81 5 90.3 92

Example 2 Polyester fiber 5 having a fiber diameter of 10 μm and a fiber length of 51 mm
A non-woven fabric having a surface density of 72 g / m ² composed of 0% by weight and 50% by weight of an acrylic resin, and a melt-blown non-woven fabric composed of polypropylene fibers having a fiber diameter of about 1 to 5 μm are laminated and partially ultrasonically fused to obtain a thickness. A filter medium having a thickness (t) of 0.75 mm was obtained. The maximum tensile strength ( _Wmax ) of the filter medium at a sample width (b) of 5 cm was 150 N. The maximum tensile stress (σ _max ) of the filter medium is 4 × 10 ⁶ N / m ² from the relation of σ _max = W _max / bt. The resistance coefficient (K) of the filter medium on a flat plate was 1.04 × 10 ⁷ (1 / m). On the other hand, the operating condition of the unit filter is that the air volume (V) is 7.2.
m ³ / min. Inlet height of the unit filter (H) is 0.2 m, the width (w) is the 0.2 m, the average flow velocity of the unit inlet side _{(u i)} is 3m from the relationship _u i = V / WH / s. The kinematic viscosity (ν) of the air was 1.51 × 10 ⁻⁵ m ² / s (20 ° C.). Further, the resistance (ΔP ^* ) of the filter medium is determined by the filter medium passage speed ( _uf ) of the fluid to be treated and the pressure loss (K ₁ ) of the filter medium at a wind speed of 1 m / s.
And ΔP ^* = K ₁ × u _f ^1.15 .
Since the filter medium passage speed ( _uf ) can be obtained by dividing the air volume by the total area of the filter medium used in the unit, _uf = V / 2NPH
= VB ^* / 2WPH (however, the number of pleats N = W / B
^* ) And can be obtained by substituting each value. Since K ₁ is a 240Pa by measuring the resistance of the filter medium from these ([Delta] P ^*) is obtained. Since the filter medium passing speed ( _uf ) changes when the pleated peak interval (B ^* ) changes, the resistance (ΔP ^* ) of the filter media also changes depending on the pleated peak interval (B ^* ). Of the pleat shape of the unit filter,
When the pleat height (P) is 0.024 m, the interval between the pleated peaks (B ^* ) is 3 mm, 4 mm, 5 mm, and 6 m.
m, the total pressure loss of the unit filter (Δ
When P ₀ ) was obtained from the equation (1), as shown in Table 2, the total pressure loss (ΔP ₀ ) at a pleat peak interval (B ^* ) of 4 mm was obtained.
Was the lowest. Based on the results, the filter medium was pleated under the conditions of a pleat height of 0.024 m and a pleat interval of 4 mm to produce a unit filter. It should be noted that, 3mm the pleats of the mountain interval ^{(B *), 4mm, 5mm} , 6mm
The filter media were pleated under the conditions described above to produce a unit filter. The total pressure loss was measured and the results are shown in Table 2. According to the actual measurement results, the total pressure loss of the unit filter pleated under the condition of the pleat peak interval of 4 mm is the lowest among the manufactured unit filters, and the pleat shape having the pleat interval determined by the formula (1) is appropriate. I understand. The values of the design conditions and operating conditions of this unit filter are as follows: resistance of the filter medium (△ P ^* ) = K ₁ × _uf ^1.15 (K ₁ = 2
40 Pa, _uf = VB ^* / 2 WPH) Filter media thickness (t) = 0.75 mm = 0.0075 mm Maximum tensile stress (σ _max ) of the filter media = 4 × 10 ⁶ N / m
⁽² ) The resistance coefficient (K) of the filter medium on a flat plate is 1.04 × 10 ⁷ (1
/ M) Average flow velocity (u _i ) on the unit inlet side = 3 m / s Kinematic viscosity of air (ν) = 1.51 × 10 ^-5 m ² / s
(20 ° C.) The pleated height (P) = 0.024 m 2, and the pleated peak interval (B *) and the total pressure loss (ΔP ₀ ) of the unit filter are as shown in Table 2.

[Table 2] Pleated peak interval B ^* (mm) ΔP ₀ calculation result (Pa) ΔP ₀ measurement result (Pa ) 3 122.5 123 4 109.7 106 5 113.4 109 6 122.4 117

Example 3 Polyester fiber 5 having a fiber diameter of 10 μm and a fiber length of 51 mm
A non-woven fabric having a surface density of 72 g / m ² composed of 0% by weight and 50% by weight of an acrylic resin, and a melt-blown non-woven fabric composed of polypropylene fibers having a fiber diameter of about 1 to 5 μm are laminated and partially ultrasonically fused to obtain a thickness. A filter medium having a thickness (t) of 0.75 mm was obtained. The maximum tensile strength ( _Wmax ) of the filter medium at a sample width (b) of 5 cm was 150 N. The maximum tensile stress (σ _max ) of the filter medium is 4 × 10 ⁶ N / m ² from the relation of σ _max = W _max / bt. The resistance coefficient (K) of the filter medium on a flat plate was 1.04 × 10 ⁷ (1 / m). On the other hand, the operating condition of the unit filter is that the air volume (V) is 7.2.
m ³ / min. Inlet height of the unit filter (H) is 0.2 m, the width (w) is the 0.2 m, the average flow velocity of the unit inlet side _{(u i)} is 3m from the relationship _u i = V / WH / s. The kinematic viscosity (ν) of the air was 1.51 × 10 ⁻⁵ m ² / s (20 ° C.). Further, the resistance (ΔP ^* ) of the filter medium is determined by the filter medium passage speed ( _uf ) of the fluid to be treated and the pressure loss (K ₁ ) of the filter medium at a wind speed of 1 m / s.
And ΔP ^* = K ₁ × u _f ^1.15 .
Since the filter medium passage speed ( _uf ) can be obtained by dividing the air volume by the total area of the filter medium used in the unit, _uf = V / 2NPH
= VB ^* / 2WPH (however, the number of pleats N = W / B
^* ) And can be obtained by substituting each value. Since K ₁ is a 240Pa by measuring the resistance of the filter medium from these ([Delta] P ^*) is obtained. Since the filter medium passage speed ( _uf ) changes as the pleat height (P) changes, the resistance (ΔP ^* ) of the filter medium also changes as a result of the pleat height (P). The total pressure loss (ΔP ₀₎ of the unit filter when the pleat height (P) is set to 15 mm, 20 mm, 25 mm, and 30 mm when the pleat peak interval (B ^* ) is 5 mm among the pleat shapes of the unit filter. ) Was determined from equation (1), and as shown in Table 3, the total pressure loss (ΔP ₀ ) at a pleat height of 30 mm was the lowest. Based on this result, the filter medium was pleated under the conditions of a pleat height of 0.03 m and a pleat interval of 5 mm to produce a unit filter. In addition, pleat height (P) is 15m
The filter medium was pleated under the conditions of m, 20 mm, 25 mm, and 30 mm to produce a unit filter, and the total pressure loss was measured. The results are shown in Table 3. According to the actual measurement results, the total pressure loss of the unit filter pleated under the condition of the pleat height of 30 mm is the lowest among the manufactured unit filters, and the pleat shape having the pleat height determined by the equation (1) is appropriate. I understand. The values of the design conditions and operating conditions of this unit filter are as follows: resistance of the filter medium (△ P ^* ) = K ₁ × _uf ^1.15 (K ₁ = 2
40 Pa, _uf = VB ^* / 2 WPH) Filter media thickness (t) = 0.75 mm = 0.0075 mm Maximum tensile stress (σ _max ) of the filter media = 4 × 10 ⁶ N / m
⁽² ) The resistance coefficient (K) of the filter medium on a flat plate is 1.04 × 10 ⁷ (1
/ M) Average flow velocity (u _i ) on the unit inlet side = 3 m / s Kinematic viscosity of air (ν) = 1.51 × 10 ^-5 m ² / s
(20 ° C.) Pleated peak interval (B ^* ) = 5 mm = 0.005 m 2. Pleated height (P) and total pressure loss (ΔP ₀ ) of the unit filter are as shown in Table 3.

[Table 3] Pleated height (mm) ΔP ₀ calculation result (Pa) ΔP ₀ measurement result (Pa) 15 160.3 151 20 128.8 119 25 110.3 106 30 98.3 95

[0019]

According to the method for manufacturing a unit filter of the present invention, the shape resistance of the unit filter is controlled by design conditions such as the pleat height, the interval between the pleat peaks and the thickness of the filter medium to be used, the average flow velocity of the fluid to be treated, and the air flow rate. It is characterized by finding that it becomes a function of operating conditions such as kinematic viscosity, and utilizing this to determine a pleat shape that becomes a unit filter having an optimum pressure loss for a filter medium to be used. For this reason, in the invention of this application, in order to obtain a unit filter having an optimum pressure loss as in the related art, it is complicated to actually manufacture a plurality of unit filters, measure the pressure loss, and determine a pleat shape for mass production. There is no need to perform complicated operations and useless unit filters. Further, according to the present invention, it is possible to easily provide a unit filter having a desired resistance (pressure loss), and it is excellent particularly when pleating using a novel filter medium.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a unit filter according to the present invention.

FIG. 2 shows the relationship between the pleated interval B * of the unit filter.
And the total pressure loss ΔP ₀Graph plotting

FIG. 3 Pleated dimensionless parameter ｛(8 / KP)
(2P / B ^* -2t) 3｝, the increase of the resistance ΔP ₀ of the unit filter with respect to the resistance ΔP ^* of the filter medium ｛(ΔP
₀ / {P ^* )-1} plotted on log-log paper

Figure 4 is a graph plotting the shape characteristic value k ₁ of unit filters of up tensile stress sigma _max and various materials filter medium of the filter medium

[Explanation of symbols]

B ^* Pleated peak interval D Filter unit depth H Filter unit height P Pleated height u Average flow velocity at the _i unit entrance side V Air flow rate W Filter unit width

 ────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Norio Kimura 3F Ikegami-cho 3-1-1F, Chikusa-ku, Nagoya-shi, Aichi 3D term (reference) 4D058 JA14 JB03 JB05 JB06 JB14 JB24 JB25 JB26 JB39

Claims (4)

[Claims] 1. A method of manufacturing a pleated unit filter, wherein the pleated shape is determined by the following equation (1). (Equation 1) (Where △ P ₀ is the total pressure loss, △ P ^* is the fluid resistance in the flat plate of the filter medium, ΔP ₁ is the shape resistance of the unit filter,
sigma _max is the maximum tensile stress of the filter medium, u _i is the average velocity of the units entrance, [nu exercise viscosity of air, B ^* mountain spacing of the pleats, P is the pleat height, t is the filter media thickness, K is flat Resistance coefficient of filter media) 2. A pleat shape is determined by calculating a total pressure loss corresponding to a peak interval between a plurality of pleats according to the equation (1), and selecting a pleat peak interval having a low total pressure loss. A method for manufacturing the unit filter according to claim 1. 3. A pleat shape is determined by calculating a total pressure loss corresponding to a plurality of pleat heights according to equation (1), and selecting a pleat height having a low total pressure loss. Item 2. A method for manufacturing a unit filter according to Item 1. 4. A total pressure loss corresponding to a combination of a plurality of pleat heights and a pleated peak interval is obtained by equation (1), and a combination of a pleat height and a pleated peak interval having a low total pressure loss is selected. The method for manufacturing a unit filter according to claim 1, wherein a pleat shape is determined.