A method for preparing a filter cotton

Abstract

The present application relates to the technical field of filter material preparation, in particular to a filter cotton preparation method. The filter cotton preparation method comprises a melt blowing step of melt blowing a melt to prepare an initial filter cotton, and a pleating step of pleating the initial filter cotton; the melt blowing step comprises: a frequency conversion motor connected with a spinneret and controlling the travel speed of the spinneret; the travel speed of the spinneret is inversely proportional to the thickness of the filter cotton; the travel speed of the spinneret is alternated between v1 and v2; the thickness of the filter cotton is alternated between D1 and D2; the pleating step comprises: obtaining a pleat angle in a thick layer; the thick layer is extruded to reduce the thickness, the thin layer is not extruded and the thickness remains unchanged, and a pleated filter cotton with uniform thickness is obtained. The filter cotton preparation method provided by the present application realizes the purpose of uniformizing the wind speed of the filtering air flow by providing a melt blowing method for controlling the thickness of the filter cotton to be alternately thin and thick, and a pleating process for forming a pleat angle in the thick layer of the filter cotton and a non-pleat angle in the thin layer, thereby obtaining a pleated filter cotton with uniform overall thickness.

Description

Technical Field

[0001] This invention relates to the field of filter material preparation technology, and specifically to a method for preparing filter cotton. Background Technology

[0002] The filter cotton is placed in the filter device for air filtration. The filter device continuously sends airflow into the laminar flow clean room. The laminar flow clean room relies on the pushing and squeezing action of the airflow to exhaust the polluted air in the room to the outside along the entire cross section, thereby achieving the purpose of purifying the indoor air. Therefore, the laminar flow clean room has extremely high requirements for the uniformity of air velocity. Uneven air velocity greatly affects the air purification effect.

[0003] Existing filtration devices generally use pleated filter cotton for air filtration; pleated filter cotton is formed by pleating flat filter media of uniform thickness, which can effectively increase the contact area between the filter cotton and the air, thereby improving filtration efficiency.

[0004] In existing technologies, after the filter cotton is pleated, the compression at the pleats causes the overall thickness of the pleated filter cotton to be uneven. This results in different resistances to airflow at different parts of the filter cotton, leading to uneven airflow speed after filtration by the pleated filter cotton, which in turn affects the air purification effect. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defect of uneven wind speed caused by uneven thickness of pleated filter cotton in the prior art, thereby providing a filter cotton preparation method that can make the overall thickness of pleated filter cotton uniform.

[0006] To solve the above-mentioned technical problems, the present invention provides a method for preparing filter cotton, comprising:

[0007] The meltblowing step for preparing initial filter cotton by meltblowing molten material, and the pleating step for pleating the initial filter cotton;

[0008] The meltblowing step includes:

[0009] Materials are mixed and melted to obtain a melt, which is then ejected from a spinneret into a rotating airflow and stretched to form fibers.

[0010] The spinneret advances, and the fibers bond together to form a continuous filter cotton;

[0011] The variable frequency motor is connected to the spinneret and controls the travel speed of the spinneret; the travel speed of the spinneret inversely controls the thickness of the filter cotton.

[0012] The travel speed of the spinneret alternates between v1 and v2, where v1 > v2;

[0013] The thickness of the filter cotton alternates between D1 and D2, where D1 < D2;

[0014] Filter cotton with a thickness of D1 is defined as a thin layer, and filter cotton with a thickness of D2 is defined as a thick layer;

[0015] The multiple thick layers are evenly spaced apart, and the distance between the center lines of adjacent thick layers is a;

[0016] The pleating step includes:

[0017] The filter cotton is fed into the pleating machine, and the spacing b of the pleating execution part of the pleating machine is adjusted so that b = a;

[0018] Adjust the relative position of the filter cotton and the pleating actuator so that the pleating actuator corresponds to the center of the thick layer and is offset from the thin layer;

[0019] The pleating actuator is activated to obtain pleats in the thick layer;

[0020] The thickness of the thick layer decreases due to compression, while the thickness of the thin layer remains unchanged without compression, resulting in pleated filter cotton with uniform thickness.

[0021] Optionally, the meltblowing step further includes controlling the travel speed of the spinneret to be 0.5m / min ≤ v2 < v1 ≤ 100m / min.

[0022] Optionally, the meltblowing step further includes: the thickness of the thick layer and the thin layer is 0.1mm≤D1<D2≤30mm.

[0023] Optionally, the melt-blowing step further includes: the melting point temperature of the molten material is a; the temperature t of the molten material is controlled to be (a-10)℃≤t≤(a+10)℃; the diameter d of the spinneret orifice is 0.15mm≤d≤0.5mm; the spinneret pressure p is 7MPa≤p≤25MPa; and the air flow rate q is 10m³ / h. 3 / min≤q≤100m 3 / min.

[0024] Optionally, the meltblowing step further includes: multiple spinnerets arranged in parallel, and the axes of the spinnerets being in the same plane;

[0025] The plane is perpendicular to the direction of travel of the spinneret.

[0026] Optionally, the meltblowing step further includes: the thick layer is formed on the side surface of the filter cotton near the spinneret;

[0027] The surface of the filter cotton away from the spinneret is flat.

[0028] Optionally, the meltblown step further includes: the width of the thick layer is w1, and the width of the thin layer is w2, wherein: 0.1cm≤w1≤w2.

[0029] Optionally, the pleating actuator is activated to obtain pleats at the thick layer; including:

[0030] The pleating machine starts from a portion of the filter cotton located at the junction between the thin and thick layers at the end of the filter cotton.

[0031] The technical solution of this invention has the following advantages:

[0032] 1. The filter cotton preparation method provided by this invention provides a melt-blowing method to control the thickness of the filter cotton to vary in an alternating manner, and a pleating process to form pleats in the thick layer and non-pleats in the thin layer of the filter cotton, thereby obtaining a pleated filter cotton with approximately uniform overall thickness. This achieves the goal of uniform airflow velocity in the filtration airflow, improving the air purification effect. The pleating process and the melt-blowing method work together to solve the problem of uneven thickness of the filter cotton after pleating, which leads to uneven airflow velocity in the filtration airflow in the prior art. By replacing the motor controlling the spinneret travel speed with a variable frequency motor, the travel speed of the spinneret alternates between high speed and low speed, thereby forming filter cotton with alternating thin and thick layers, which is highly practical. Attached Figure Description

[0033] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0034] Figure 1 This is a front view of the filter cotton preparation process of the present invention;

[0035] Figure 2 This is a schematic diagram of the filter cotton preparation process of the present invention.

[0036] Explanation of reference numerals in the attached figures:

[0037] 1. Spinneret; 2. Filter cotton; 21. Thick layer; 22. Thin layer. Detailed Implementation

[0038] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0039] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0040] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0041] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0042] Example 1

[0043] Combination Figures 1-2 As shown, the filter cotton preparation method provided in this embodiment includes:

[0044] The process includes a meltblowing step to prepare initial filter cotton 2, and a pleating step to pleat the initial filter cotton 2; the meltblowing step includes: mixing and melting materials to obtain a melt, and extruding the melt from a spinneret 1 into a rotating airflow to stretch and form fibers; the spinneret 1 advances, and the fibers bond together to form continuous filter cotton 2; wherein a variable frequency motor is connected to the spinneret 1 and controls the travel speed of the spinneret 1; the travel speed of the spinneret 1 inversely controls the thickness of the filter cotton 2; the travel speed of the spinneret 1 alternates between v1 and v2, where v1 > v2; the thickness of the filter cotton 2 alternates between D1 and D2, where D1 < D2; the thickness is defined. Filter cotton 2 with thickness D1 is defined as thin layer 22, and filter cotton 2 with thickness D2 is defined as thick layer 21; multiple thick layers 21 are evenly spaced, and the distance between the center lines of adjacent thick layers 21 is a; the pleating step includes: feeding the filter cotton 2 into a pleating machine, adjusting the distance b of the pleating execution part of the pleating machine so that b = a; adjusting the relative position of the filter cotton 2 and the pleating execution part so that the pleating execution part corresponds to the center of the thick layer 21 and is offset from the thin layer 22; the pleating execution part is activated to obtain a pleat at the thick layer 21; the thick layer 21 is compressed and its thickness decreases, while the thin layer 22 is not compressed and its thickness remains unchanged, thus obtaining a pleated filter cotton with uniform thickness.

[0045] In this embodiment, by replacing the motor controlling the travel speed of the spinneret 1 with a variable frequency motor, the travel speed of the spinneret 1 alternates between v1 and v2, where v1 > v2. The travel speed of the spinneret 1 is inversely proportional to the thickness of the filter cotton 2, thereby forming a filter cotton 2 with alternating thin layers 22 and thick layers 21. At the same time, when pleating, pleats are formed at the thick layer 21 of the filter cotton 2, and non-pleats are formed at the thin layer 22. Due to the compression effect brought about by pleating, the overall thickness of the pleated filter cotton tends to be uniform, thereby achieving the purpose of making the airflow speed of the filter airflow uniform.

[0046] Combination Figures 1-2As shown, during the meltblown process, the spinneret 1 sprays the molten material into a rotating airflow to stretch and form fibers. The spinneret 1 then advances, causing the fibers to bond and form a continuous filter cotton 2. A variable frequency motor controls the travel speed of the spinneret 1 to alternate between v1 and v2, where v1 > v2. This causes the thickness of the filter cotton 2 to alternate between D1 and D2, where D1 < D2. After continuous meltblown operation, an initial filter cotton 2 with alternating thicknesses is generated. The initial filter cotton 2 is then fed into a pleating machine, where a spaced-out stamping pleating method is used to confirm the thin layer 22 and the thick layer 21 of the initial filter cotton 2. The position is determined by obtaining the distance 'a' between the center lines of adjacent thick layers 21, and adjusting the distance 'b' between the pleating execution parts in the pleating machine so that 'b=a'; the relative position of the filter cotton 2 and the pleating execution part is adjusted so that the pleating execution part corresponds to the center of the thick layer 21 and is offset from the thin layer 22, to ensure that pleats are formed in the thick layer 21 and non-pleats are formed in the thin layer 22; the pleating machine takes the portion of filter cotton 2 located at the junction between the thin layer 22 and the thick layer 21 at the end of the filter cotton 2 as the starting point, and pleats it. The thick layer 21 is compressed and its thickness decreases, while the thin layer 22 is not compressed and its thickness remains unchanged, thus obtaining a pleated filter cotton with a relatively uniform thickness.

[0047] Furthermore, during the melt-blowing process, the travel speed of the spinneret 1 must be controlled to be 0.5 m / min ≤ v2 < v1 ≤ 100 m / min, the diameter d of the spinneret orifice of the spinneret 1 must be 0.15 mm ≤ d ≤ 0.5 mm, the spinneret pressure p of the spinneret 1 must be 7 MPa ≤ p ≤ 25 MPa, and the air flow rate q must be 10 m³ / min. 3 / min≤q≤100m 3 / min.

[0048] The melt temperature was 275 degrees Celsius, the spinneret pressure was 15 MPa, and the air flow rate was 45 m³ / h. 3 The implementation effects are shown in the table below when the travel speed is v2 = 10 m / min and 3 m / min ≤ v2 ≤ 10 m / min:

[0049]

[0050] In Examples 1 to 3 above, the same values ​​of melt temperature, spinneret pressure, and airflow were controlled. In Example 1, the travel speed v1 = v2 = 10 m / min, and the pleat angle of filter cotton 2 after pleating was 30 degrees. In Example 2, the travel speed v1 = 10 m / min, 3 m / min ≤ v2 ≤ 9 m / min, and the pleat angle of filter cotton 2 after pleating was 30 degrees. In Example 3, the travel speed v1 = 10 m / min, 3 m / min ≤ v2 ≤ 9 m / min, and the pleat angle of filter cotton 2 after pleating was 15 degrees. The smaller the difference in wind speed between the pleated and non-pleated areas, the higher the wind speed uniformity of the pleated filter cotton.

[0051] Combining Examples 1 and 2, compared with pleated filter cotton formed at the same travel speed, pleated filter cotton formed at different travel speeds has higher uniformity of overall thickness after pleating because the pleated filter cotton 2 formed at different travel speeds has higher uniformity of wind speed. Combining Examples 2-1 to 2-4, when the pleating angle of filter cotton 2 is 30 degrees, the uniformity of wind speed is the highest at travel speeds v1 = 10 m / min and v2 = 5 m / min. The wind speed at the pleated and non-pleated areas is basically equal, and the overall wind speed of filter cotton 2 is basically uniform.

[0052] Combining Examples 3-1 to 3-4, when the pleating angle of filter cotton 2 is 15 degrees, the uniformity of wind speed is the highest when the travel speed is v1 = 10 m / min and v2 = 3 m / min. The wind speed at the pleated and non-pleated areas is basically equal, and the overall wind speed of filter cotton 2 is basically uniform.

[0053] In this embodiment, a meltblown method is provided to control the thickness of the filter cotton 2 to vary in an alternating manner, and a pleating process is provided to form pleats in the thick layer 21 and non-pleats in the thin layer 22 of the filter cotton 2. This results in a pleated filter cotton with approximately uniform overall thickness, achieving the goal of uniform airflow velocity and improving air purification effect. The pleating process and meltblown method work together to solve the problem in the prior art where the thickness of the filter cotton 2 is uneven after pleating, leading to uneven airflow velocity. By replacing the motor controlling the travel speed of the spinneret 1 with a variable frequency motor, the travel speed of the spinneret 1 alternates between high speed and low speed, thereby forming a filter cotton 2 with alternating thin layer 22 and thick layer 21, which is highly practical.

[0054] Specifically, the meltblowing step further includes controlling the travel speed of the spinneret 1 to be 0.5m / min≤v2<v1≤100m / min.

[0055] Specifically, the meltblowing step further includes: the thickness of the thick layer 21 and the thin layer 22 is 0.1mm≤D1<D2≤30mm.

[0056] Combination Figure 1 As shown, the traveling speed of the spinneret 1 is inversely proportional to the thickness of the filter cotton 2. The faster the traveling speed, the thinner the filter cotton 2, and the slower the traveling speed, the thicker the filter cotton 2. The traveling speed of the spinneret 1 can be 0.5m / min≤v2<v1≤100m / min, so that the thickness of the thick layer 21 and the thin layer 22 of the filter cotton 2 can be 0.1mm≤D1<D2≤30mm.

[0057] Specifically, the melt-blowing step further includes: the melting point temperature of the molten material is a; the temperature t of the molten material is controlled to be (a-10)℃≤t≤(a+10)℃; the diameter d of the spinneret 1 is 0.15mm≤d≤0.5mm; the spinneret pressure p of the spinneret 1 is 7MPa≤p≤25MPa; and the air flow rate q is 10m³ / h. 3 / min≤q≤100m 3 / min.

[0058] Combination Figure 1 As shown, the temperature t of the molten material is controlled within ±10°C of the melting point; a spinneret 1 is provided with a spinneret hole, from which the molten material is ejected; the diameter of the spinneret hole should not be too small to prevent clogging. In this embodiment, the diameter d of the spinneret hole is 0.15mm≤d≤0.5mm, and the spinneret pressure p is 7MPa≤p≤25MPa to obtain excellent spinneret effect.

[0059] Specifically, the meltblowing step further includes: multiple spinnerets 1 are arranged in parallel, and the axes of the spinnerets 1 are in the same plane;

[0060] The plane is perpendicular to the direction of travel of the spinneret 1.

[0061] Combination Figure 2 As shown, multiple spinnerets 1 are arranged in parallel, and each spinneret 1 is perpendicular to the plane where the filter cotton 2 is located; the multiple spinnerets 1 move synchronously, so that the thickness of the thick layer 21 and the thin layer 22 of the filter cotton 2 are consistent, thereby improving the uniformity of the overall thickness of the filter cotton 2 after pleating.

[0062] Specifically, the meltblowing step further includes: the thick layer 21 is formed on the surface of the filter cotton 2 near the spinneret 1;

[0063] The surface of the filter cotton 2 away from the spinneret 1 is flat.

[0064] Combination Figure 1 As shown, the multiple spinnerets 1 are all located on the same side of the filter cotton 2, so that the protrusions of the thick layer 21 are all located on the same side of the filter cotton 2, and are on the side of the filter cotton 2 closest to the spinnerets 1. The surface of the filter cotton 2 away from the spinnerets 1 is flat.

[0065] Specifically, the meltblown step further includes: the width of the thick layer 21 is w1, and the width of the thin layer is w2, wherein: 0.1cm≤w1≤w2.

[0066] Combination Figure 1As shown, the dimensional relationship between the width w1 of the thick layer 21 and the width w2 of the thin layer 22 is 0.1cm≤w1≤w2. Different specifications and dimensions can be selected according to different usage requirements.

[0067] Specifically, the pleating actuator is activated to obtain a pleat at the thick layer 21; including:

[0068] The pleating machine starts from a portion of the filter cotton 2 located at the junction between the thin layer 22 and the thick layer 21 at the end of the filter cotton 2.

[0069] During pleating, the relative positions of the filter cotton 2 and the pleating execution part are adjusted so that the pleating execution part corresponds to the center of the thick layer 21 and is offset from the thin layer 22. The pleating machine takes the part of the filter cotton 2 located at the junction between the thin layer 22 and the thick layer 21 at the end of the filter cotton 2 as the starting point to obtain a pleated filter cotton with a relatively uniform thickness.

[0070] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for preparing filter cotton, characterized in that, include: The meltblowing step for preparing initial filter cotton by meltblowing molten material, and the pleating step for pleating the initial filter cotton; The meltblowing step includes: Materials are mixed and melted to obtain a melt, which is then ejected from a spinneret into a rotating airflow and stretched to form fibers. The spinneret advances, and the fibers bond together to form a continuous filter cotton; The variable frequency motor is connected to the spinneret and controls the travel speed of the spinneret; the travel speed of the spinneret inversely controls the thickness of the filter cotton. The travel speed of the spinneret alternates between v1 and v2, where v1 > v2; The thickness of the filter cotton alternates between D1 and D2, where D1 < D2; Filter cotton with a thickness of D1 is defined as a thin layer, and filter cotton with a thickness of D2 is defined as a thick layer; The multiple thick layers are evenly spaced apart, and the distance between the center lines of adjacent thick layers is a; The pleating step includes: The filter cotton is fed into the pleating machine, and the spacing b of the pleating execution part of the pleating machine is adjusted so that b = a; Adjust the relative position of the filter cotton and the pleating actuator so that the pleating actuator corresponds to the center of the thick layer and is offset from the thin layer; The pleating actuator is activated to obtain pleats in the thick layer; The thickness of the thick layer decreases due to compression, while the thickness of the thin layer remains unchanged without compression, resulting in pleated filter cotton with uniform thickness.

2. The method for preparing filter cotton according to claim 1, characterized in that, The meltblowing step further includes controlling the travel speed of the spinneret to be 0.5m / min≤v2<v1≤100m / min.

3. The method for preparing filter cotton according to claim 1, characterized in that, The meltblowing step further includes: the thickness of the thick layer and the thin layer is 0.1mm≤D1<D2≤30mm.

4. The method for preparing filter cotton according to claim 1, characterized in that, The melt-blowing step further includes: the melting point temperature of the molten material is a; the temperature t of the molten material is controlled to be (a-10)℃≤t≤(a+10)℃; the diameter d of the spinneret orifice is 0.15mm≤d≤0.5mm; the spinneret pressure p is 7MPa≤p≤25MPa; and the air flow rate q is 10m³ / h. 3 / min≤q≤100m 3 / min.

5. The method for preparing filter cotton according to claim 1, characterized in that, The melt-blowing step further includes: multiple spinnerets are arranged in parallel, and the axes of the spinnerets are in the same plane; The plane is perpendicular to the direction of travel of the spinneret.

6. The method for preparing filter cotton according to claim 1, characterized in that, The meltblowing step further includes: the thick layer is formed on the surface of the filter cotton near the spinneret; The surface of the filter cotton away from the spinneret is flat.

7. The method for preparing filter cotton according to claim 1, characterized in that, The meltblown step further includes: the width of the thick layer is w1, and the width of the thin layer is w2, wherein: 0.1cm≤w1≤w2.

8. The method for preparing filter cotton according to claim 1, characterized in that, The pleating actuator is activated to obtain pleats in the thick layer; including: The pleating machine starts from a portion of the filter cotton located at the junction between the thin and thick layers at the end of the filter cotton.

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