Preparation method of filter

Abstract

The invention discloses a filter preparation method, which comprises: (1) preparing an annular filtration main body: pleating a non-woven fabric to form a continuously-bent V-shaped structure, connecting two end surfaces parallel to the folding edge of the V-shaped structure to form a closed ring so as to prepare the annular filtration main body, and bonding the two adjacent edges of the V-shaped structure through a colloid so as to prepare the annular filtration main body, the length of the rubber body is 54-70% of the height of the folded edge of the V-shaped structure, and the distance between the highest part of the rubber body and the peak edge of the V-shaped structure is 30-46% of the height of the folded edge; (2) preparing a sealing part: stamping the bendable sealing part through a stamping device to obtain an annular sealing part; (3) preparing a hard supporting part: carrying out injection molding by adopting synthetic resin to prepare the hard supporting part with the thickness of 2-10mm; and (4) assembling the sealing part and the annular filtering main body to obtain the filter. The filter prepared by the preparation method has the characteristics of high efficiency and low resistance.

Description

Technical Field

[0001] The invention relates to a method for preparing a filter. Background Art

[0002] In recent years, the types of filters have gradually increased. Generally, in the prior art, the adjacent folded edges of the filter are bonded by colloid, and the length of the colloid is the same as the height of the folded edge. Although the shape of the filter can be fixed, the longer colloid will squeeze the adjacent folded edges, so that the distance between the folded edges is reduced, thereby reducing the filtration efficiency of the filter. In addition, there are also methods for preparing cylindrical filters on the market, but they have the problems of high production defect rate and low production efficiency.

[0003] For example, Chinese utility model patent CN217988737U discloses a flexible purification component and a filter device having the same, wherein the flexible purification component includes a folded filter surface and a flexible bracket arranged inside the filter surface. Since the bracket is arranged inside the folded filter surface and extends from the upper end of the filter surface to the lower end of the filter surface, occupying 100% of the height of the folded edge of the filter surface, the wind resistance of the purification component is very high.

[0004] For example, Chinese invention patent CN114053802A discloses a soft frame filter element and its preparation method. In the filter element preparation method, a receiving groove is first set on the soft frame, and then the cylindrical filter element body is inserted into the receiving groove of the soft frame to obtain the soft frame filter element. This process has high requirements for the matching of the width dimension of the receiving groove and the folded height dimension of the filter element body. If the dimensions do not match, there will be a high defective rate of failure to insert, and it takes a long time to accurately insert the frame receiving groove, resulting in reduced production efficiency. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing a filter with high production efficiency. The filter prepared by the method has the characteristics of high efficiency and low resistance.

[0006] The technical solution of the present invention is as follows: The preparation method of the filter of the present invention comprises the following steps:

[0007] (1) Preparation of an annular filter body: a nonwoven fabric is pleated to form a continuously bent V-shaped structure, and two end surfaces parallel to the folded edge of the V-shaped structure are connected to form a closed ring to obtain an annular filter body, wherein the adjacent two sides of the V-shaped structure are bonded by a colloid, the length of the colloid is 54-70% of the height of the folded edge of the V-shaped structure, and the distance between the highest part of the colloid and the peak edge of the V-shaped structure is 30-46% of the height of the folded edge;

[0008] (2) Preparation of the sealing portion: punching the bendable sealing portion by a punching device to obtain an annular sealing portion;

[0009] (3) Preparation of the hard support portion: using synthetic resin for injection molding to obtain a hard support portion with a thickness of 2 to 10 mm;

[0010] (4) Assembling the sealing part and the annular filter body to obtain a filter, the specific assembly steps are as follows:

[0011] S1. Place the sealing part in the assembly mold, wherein a limited position shaping component is provided in the middle of the inner ring of the assembly mold, the width of the inner ring is equal to the height of the folded edge of the annular filter body, and the width of the outer ring of the assembly mold is 2 to 10 mm;

[0012] S2. Spraying the hot pressure-sensitive adhesive on the sealing portion;

[0013] S3. Place one end of the annular filter body on the surface of the sealing portion after the glue is applied;

[0014] S4. Pressing the other end of the annular filter body in step S3 downwardly by the pressing device, the sealing portion is fitted with the circumference of the annular filter body;

[0015] S5. Use the same method as steps S2 to S4 to complete the bonding of the other end sealing part.

[0016] Beneficial effects of the present invention: The filter prepared by the preparation method of the present invention has the characteristics of high efficiency and low resistance. The preparation method of the filter can easily complete the edge wrapping of the flexible sealing part, achieving the excellent effects of high air tightness and no glue overflow. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the structure of the filter of the present invention, wherein: 1 is a compressible and deformable annular filter body, 2 is a bendable sealing portion, 3 is a detachable hard support portion, 4 is a coarse filter layer, and 5 is a colloid.

[0018] Figure 2 It is a schematic diagram of the structure of the filter of the present invention after folding and compression, wherein: 2 is a bendable sealing portion, and 4 is a coarse filter layer.

[0019] Figure 3 It is a top view of the assembled mold, where 6-1 is the outer ring, 6-2 is the inner ring, and 6-3 is the limiting fixture.

[0020] Figure 4 It is a cross-sectional view of the assembled mold, where: 6-1-1 is the outer ring surface, 6-2-1 is the inner ring surface, 6-3 is the limit fixture, and 6-4 is the spring. DETAILED DESCRIPTION

[0021] The preparation method of the filter of the present invention comprises the following steps:

[0022] (1) Preparation of an annular filter body: a nonwoven fabric is pleated to form a continuously bent V-shaped structure, and two end surfaces parallel to the folded edge of the V-shaped structure are connected to form a closed ring to obtain an annular filter body, wherein the adjacent two sides of the V-shaped structure are bonded by a colloid, the length of the colloid is 54-70% of the height of the folded edge of the V-shaped structure, and the distance between the highest part of the colloid and the peak edge of the V-shaped structure is 30-46% of the height of the folded edge;

[0023] (2) Preparation of the sealing portion: punching the bendable sealing portion by a punching device to obtain an annular sealing portion;

[0024] (3) Preparation of the hard support portion: using synthetic resin for injection molding to obtain a hard support portion with a thickness of 2 to 10 mm;

[0025] (4) Assembling the sealing part and the annular filter body to obtain a filter, the specific assembly steps are as follows:

[0026] S1. Place the sealing part in the assembly mold, wherein a limited position shaping component is provided in the middle of the inner ring of the assembly mold, the width of the inner ring is equal to the height of the folded edge of the annular filter body, and the width of the outer ring of the assembly mold is 2 to 10 mm;

[0027] S2. Spraying the hot pressure-sensitive adhesive on the sealing portion;

[0028] S3. Place one end of the annular filter body on the surface of the sealing portion after the glue is applied;

[0029] S4. Pressing the other end of the annular filter body in step S3 downwardly by the pressing device, the sealing portion is fitted with the circumference of the annular filter body;

[0030] S5. Use the same method as steps S2 to S4 to complete the bonding of the other end sealing part.

[0031] The filter of the present invention comprises the annular filter body, a sealing part and a hard support part prepared in the above steps (1) to (3), the annular filter body is preferably compressible and deformable, the sealing part is bendable, the hard support part is preferably detachable, the bendable sealing part is fixed at both ends of the annular filter body, the annular filter body is a V-shaped structure, the adjacent two sides of the V-shaped structure are bonded by colloid, the length of the colloid is 54-70% of the height of the folded edge of the V-shaped structure, and the distance between the highest part of the colloid and the peak edge of the V-shaped structure is 30-46% of the folded height. Among them, the filter body is in a flexible state and is in a flat plate shape before deformation, which is convenient for transportation and saves storage space. It can be deformed into a shape matching the filter device, such as a circle, a square, a rectangle, etc. The sealing part is in a bendable state and is fixed to the two sides perpendicular to the folded edge of the filter body by the colloid, and the length of the sealing part is equal to the length of the folded edge of the filter body. The connecting part is a component that connects the two sides of the folded edge of the filter body when the filter body is deformed, thereby ensuring the air tightness of the closed-loop three-dimensional filter element.

[0032] The above-mentioned hard support part is preferably a detachable part. When the filter is compressed, the hard support part can be placed horizontally in the hollow position of the filter in the compressed state, and does not need to be packaged and transported separately, which can make good use of the packaging and transportation space and save transportation costs. When the filter in the compressed state needs to be installed in the purifier, the support part is first taken out from the hollow position of the filter and then installed at both ends of the filter.

[0033] The thickness of the hard support part is 2 to 10 mm, preferably 2 to 6 mm. If the thickness is too thin, the strength of the support part is weakened, and it is easy to break during use, thereby affecting assembly; if the thickness is too thick, when the support part is installed in the hollow position at both ends of the filter, the diameter of the hollow position of the filter will be reduced, that is, the diameter of the air outlet hole will be reduced, thereby affecting the filtering effect of the filter.

[0034] The filter body is an annular structure, formed by connecting flat V-shaped folded filter paper end to end, and the adjacent two sides are bonded by colloid. When the ends are connected into an annular shape, since the colloid is located in the middle of the V-shaped folded peak edge, there is no colloid at the peak end of the V-shaped folded edge, that is, the length of the bonding colloid is 54-70% of the folded edge height, and the distance between the highest part of the bonding colloid and the V-shaped peak edge is 30-46% of the folded height, the inner filter surface will not be squeezed, and the outer filter surface will not be seriously stretched. If the length of the colloid is too short, when the adjacent folded edges of the outer filter surface are stretched against each other, the adhesion of the colloid is small and it is easy to break, thereby causing the filter to deform and increase the wind resistance; if the length of the colloid is too long, when the adjacent folded edges of the inner filter surface are squeezed against each other, the resistance of the colloid to the folded edges increases, and the difficulty of connecting the ends into an annular structure increases, and the filter element may be broken. In order to facilitate the connection of the V-shaped pleated filter paper end to end into a ring shape, the adhesive colloid is set in the middle position in the direction of the folded edge height. If the length of the colloid is fixed, the distance between its highest part and the V-shaped peak edge is excessively less than the folded edge height, that is, the distance between the lowest part of the colloid and the other end of the V-shaped peak edge is excessively greater than the folded edge height, one end of the colloid is closer to one side of the V-shaped peak edge, and the other end of the colloid is farther from the other side of the V-shaped peak edge. When the filter element is bent end to end toward the end where the highest part of the colloid is closer to the V-shaped peak edge, the colloid between adjacent folded edges on the inner filter surface will hinder the extrusion between adjacent folded edges, thereby affecting the deformation of the filter element, and the folded edges on the outer filter surface stretch each other, resulting in the rupture of the stretched part of the colloid.

[0035] The material of the above-mentioned flexible sealing part is preferably foam, which is flexible, lightweight, has good resistance to high and low temperatures and excellent air tightness, and can meet the requirements of bendability and foldability in the present invention. At the same time, it can also ensure the use requirements under different environmental requirements, thereby further ensuring the air tightness of the filter.

[0036] The above-mentioned bendable sealing part is fixed at both ends of the annular filter body through an assembly mold. The width of the sealing part must be greater than the height of the folding edge. If it is less than the height of the folding edge, after the sealing part and the filter body ring edge are attached, the filter body will leak when in use, thereby reducing the filtration efficiency of the filter; if it is exactly equal to the height of the folding edge, when the sealing part and the filter body ring edge are attached through the colloid, the colloid will overflow, thereby affecting the assembly of the filter body and the purifier, and the appearance of the filter body. Therefore, the width of the bendable sealing part is preferably greater than 2 to 6 mm of the height of the folding edge of the filter body, and the excess part is folded through the mold along the circumference of the annular filter body to the outer and inner circles of the filter body ring edge and attached to the inner and outer circle surfaces of the filter body, thereby avoiding leakage and overflow of glue.

[0037] The bendable sealing part is bonded to the filter body by a heat-sensitive adhesive, which is a kind of adhesive that is resistant to high and low temperatures and remains soft after being cured at room temperature. Considering the transportation and use environment, the adhesive has no flow or slippage in a high temperature environment of about 70°C, and no cracks in a low temperature environment of about -20°C.

[0038] The preparation method of the filter of the present invention preferably includes the preparation of a pre-filter, and the method is as follows: a polyamide net or a polyester net material is circled and connected to form a pre-filter. The pre-filter is a coarse filter layer, which is arranged in the outermost layer. The coarse filter layer can intercept large suspended matter such as dust and lint in the environment. After the filter is used for a period of time, if there is too much dust on the coarse filter layer, the filter can be taken out, and after cleaning the coarse filter layer, it can be put into the filter for continued use. Since the filter of the present invention is an annular structure, the coarse filter layer is ultrasonically welded from the two ends of the initial rectangle into an annular shape, and the width of the welding seam is preferably 2.0 to 5.0 mm. If it is too narrow, the filter will cause the coarse filter layer to break at the splicing of the coarse filter layer during the compression deformation process; if it is too wide, the filter area will be reduced, resulting in an increase in the wind resistance of the filter and a weakening of the filtering effect. Considering the wind resistance and filtering efficiency of the filter layer, the width of the welding seam is more preferably 2.0 to 3.0 mm.

[0039] The above-mentioned coarse filter layer is a polyamide mesh or a polyester mesh. The polyamide mesh has excellent heat resistance and wear resistance. When used in a higher temperature environment, the wear-resistant polyamide mesh can meet the needs of multiple cleanings of the coarse filter layer, thereby increasing the service life of the filter; the polyester mesh not only has good heat resistance, but also has good fatigue resistance and friction resistance, which can meet the needs of repeated cleaning of the coarse filter layer.

[0040] The wire diameter of the above-mentioned coarse filter layer is 0.15-0.30mm. If it is too thin, the strength of the coarse filter layer will be weakened. When the filter is compressed, the stress will easily cause the mesh to break, thus affecting the use of the filter; if it is too coarse, the pore size of the coarse filter layer will be reduced, thereby reducing the ventilation area and increasing the resistance of the filter.

[0041] The method for assembling the bendable sealing portion and the annular filter body in the preparation method of the filter of the present invention comprises the following steps:

[0042] S1. Place the sealing part in the assembly mold, wherein a limited position shaping component is provided in the middle of the inner ring of the assembly mold, the width of the inner ring is equal to the height of the folded edge of the annular filter body, and the width of the outer ring of the assembly mold is 2 to 10 mm;

[0043] S2. Spraying the hot pressure-sensitive adhesive on the sealing portion;

[0044] S3. Place one end of the annular filter body on the surface of the sealing portion after the glue is applied;

[0045] S4. Pressing the other end of the annular filter body in step S3 downwardly by the pressing device, the sealing portion is fitted with the circumference of the annular filter body;

[0046] S5. Use the same method as steps S2 to S4 to complete the bonding of the other end sealing part.

[0047] The bendable sealing portion in the above S1 is fixed at both ends of the annular filter body by an assembly mold. The inner ring width of the assembly mold is equal to the folding edge height of the annular filter body. During the assembly process, one end of the filter body is under pressure. When the inner ring moves downward, the filter body smoothly moves downward with the inner ring. The sealing portion located in the inner ring part will fit with the folding edge of the annular filter body, and the sealing portion located in the outer ring part will fit with the inner and outer surfaces of the annular filter body to achieve the effect of wrapping. If the inner ring width of the assembly mold is smaller than the folding edge height of the filter body, when the inner ring moves downward, due to the large folding edge height, it will be difficult for the filter body to follow the inner ring to move downward, resulting in the inability of the sealing portion to fit; if the inner ring width of the assembly mold is greater than the folding edge height, when the inner ring moves downward, the portion of the sealing portion that exceeds the folding edge height will not fit tightly with the annular filter body, which will affect the overall appearance and sealing of the filter.

[0048] The outer ring width of the assembly mold in the above S1 is 2 to 10 mm. Since the width of the flexible sealing portion is preferably greater than the folding edge height of the filter body by 2 to 6 mm, the portion of the sealing portion that exceeds the folding edge will be laid flat on the outer ring surface of the assembly mold. If the width of the assembly mold is too small, the assembly mold will be difficult to process and will not be able to support the sealing portion. If the width of the assembly mold is too large, the mold manufacturing cost will increase.

[0049] The inner ring surface of the assembly mold in S1 above is preferably a retractable ring surface, and the inner ring part will move downward as the pressure is pressed down during molding. In order to ensure a better retractable state of the inner ring, the lower surface of the inner ring surface is supported by a spring, and the lowering height of the inner ring surface is preferably 2 to 8 mm. Since the width of the flexible sealing portion is preferably greater than 2 to 6 mm of the height of the folding edge of the filter body, if the lowering height value of the inner ring surface is less than the width value of the sealing portion exceeding the folding edge height of the filter body, the exceeding portion of the sealing portion is not tightly fitted to the surface of the filter body; if the lowering height value of the inner ring surface is too greater than the width value of the sealing portion exceeding the folding edge height of the filter body, higher requirements are placed on the metal properties of the spring, that is, the manufacturing cost of the assembly mold is increased.

[0050] The hot pressure-sensitive adhesive in the above S2 is heated to 120-200°C in the glue box. If the temperature is too low, the fluidity of the adhesive will deteriorate and it will be difficult to evenly spread on the surface of the flexible sealing cotton. When the cotton is fitted with the edge of the annular filter body, there will be a lack of adhesive on the fitting surface, resulting in a weak bond. If the temperature is too high, the hot melt adhesive molecules will change in nature, the viscosity of the adhesive will weaken, and the color of the colloid will turn yellow, affecting the appearance.

[0051] The curing time of the hot pressure-sensitive adhesive in the above S2 is preferably 60s to 120s. If the time is too short, the adhesive will be cured before the bonding process between the sealing part and the annular filter body is completed; if the time is too long, the bonding process between the sealing part and the annular filter body is completed, but the adhesive is still in an uncured state, and the sealing cotton and the annular filter body are prone to peeling.

[0052] The filter of the present invention has various shapes, such as cylindrical, elliptical, square cylindrical, etc. Considering matching with the purifier device currently on the market, the filter of the present invention is preferably cylindrical or square cylindrical.

[0053] The present invention is further described by the following examples, but the protection scope of the present invention is not limited to the examples. The physical property parameters in the examples are measured by the following methods.

[0054] [Folding edge height of V-shaped structure]

[0055] Place the filter vertically on a flat surface, use a clamp to clamp the edge of the sealing part, remove the sealing part little by little, and use a degumming agent to remove the colloid on the edge of the filter body. After the colloid is removed, take out the annular filter body, lay it flat and place it horizontally, use a vernier caliper with an accuracy of 0.02mm, measure the height of the V-folded edge at both ends of the length direction of the annular filter body, and measure 3 groups of data evenly on each end of the V-folded edge, totaling 6 groups of data at both ends, and calculate the average value.

[0056]

Length of colloid

[0057] Place the filter vertically on a flat surface, use a clamp to clamp the edge of the seal, remove the seal little by little, and use a degumming agent to remove the colloid on the edge of the filter body. After the colloid is completely removed, take out the annular filter body, and use a vernier caliper with an accuracy of 0.02mm to measure the distance between the two ends of the colloid length direction of the folded edge of the V-shaped structure of the annular filter body. Randomly select 10 folded edges of the V-shaped structure for measurement. The number of colloids set on each folded edge of the V-shaped structure along the width direction of the annular filter body is n. There are a total of 10n data for the folded edges of the 10 V-shaped structures, and calculate their average value. The calculation formula is as follows:

[0058] X n: colloid length of each colloid (unit: mm);

[0059] Average colloid length (unit: mm);

[0060] n: n=1, 2, 3, 4, 5...

[0061] [The distance between the highest part of the colloid and the edge of the V-shaped structure peak]

[0062] Place the filter vertically on a flat surface, use a clamp to hold the edge of the seal, remove the seal little by little, and use a degumming agent to remove the colloid on the edge of the filter body. After the colloid is removed, take out the annular filter body, lay it flat and place it horizontally, use a tool to separate the folded edges of the adjacent V-shaped structures, designate one side of the V-shaped peak edge as the reference edge, and the distance between the two ends of the colloid in the length direction of the folded edge and the end closer to the V-shaped reference edge is the highest part of the colloid. Use a vernier caliper with an accuracy of 0.02mm to measure the distance between the highest part of the colloid and the reference peak edge of the V-shaped structure. Randomly select 10 folded edges. The number of colloids set along the width direction of the annular filter body on each V-shaped structure folded edge is n. The folded edges of the 10 V-shaped structures have a total of 10n data, and the average value is calculated. The calculation formula is as follows:

[0063] d n : The distance between the highest part of each colloid and the peak edge of the V-shaped structure (unit: mm);

[0064] The average distance between the highest part of the colloid and the peak edge of the V-shaped structure (unit: mm);

[0065] n: n=1, 2, 3, 4, 5...

[0066]

Thickness of support part

[0067] First, remove the hard support part from the filter, then place the support part horizontally, use a vernier caliper with an accuracy of 0.02mm to measure the thickness of the ring edge of the support part, measure 6 groups of data evenly, and calculate the average value.

[0068] [Distance from inner ring to outer ring of seal]

[0069] Place the filter horizontally, clamp the edge of the seal with a clamp, use a debonding agent to separate the seal from the filter body, place the separated seal horizontally, and use a vernier caliper with an accuracy of 0.02mm to measure the distance from the inner circle to the outer circle of the seal. Measure 3 groups of data evenly along the circumference and calculate the average value.

[0070] [Welding seam width of coarse filter layer]

[0071] Place the filter vertically on a flat surface, use a clamp to hold the edge of the seal, remove the seal little by little, and use a degumming agent to remove the colloid on the edge of the filter body. After the colloid is removed, take out the coarse filter and place it horizontally. Use a vernier caliper with an accuracy of 0.02mm to measure the welding seam width of the coarse filter layer. Measure 3 groups of data evenly and calculate the average value.

[0072] [Wire diameter of coarse filter layer]

[0073] Place the filter vertically on a flat surface, use a clamp to hold the edge of the seal, remove the seal little by little, and use a degumming agent to remove the colloid on the edge of the filter body. After the colloid is removed, take out the coarse filter, peel off 5 interwoven wires, use a vernier caliper with an accuracy of 0.02mm to measure the peeled wire diameter, and calculate the average value.

[0074] [Inner ring width of assembly mold]

[0075] Place the assembled mold horizontally, use a vernier caliper with an accuracy of 0.02mm to measure the inner ring width of the assembled mold, measure 6 groups of data along the edge of the ring, and calculate the average value.

[0076] [Outer ring width of assembly mold]

[0077] Place the assembled mold horizontally, use a vernier caliper with an accuracy of 0.02mm to measure the outer ring width of the assembled mold, measure 6 groups of data along the edge of the ring, and calculate the average value.

[0078] [Heating temperature of HPA in glue box]

[0079] At the beginning of the gluing process, an infrared temperature detector is used to measure the temperature of the glue nozzle. Five sets of data are detected continuously and the average value is calculated.

[0080]

Curing time of heat-sensitive adhesive

[0081] Use the glue curing time tester, put the glue into the test instrument, start the test instrument to complete the glue curing time test.

[0082] [Pressure loss and filtration efficiency]

[0083] According to the JIS B9908 (2011) test method, the evaluation sample is set in the evaluation machine, and the air is passed through the filter element at a velocity of 3.2 m / min to calculate the pressure loss of the filter. Then KCL particles are supplied from the upstream side, and the number of particles before and after the evaluation filter is measured using a particle counter. The filtration efficiency is calculated using the following formula: η = (1-(C0 / C1)) × 100,

[0084] C0: the number of particles with a particle size of 0.3 to 0.5 μm after passing through the evaluation filter,

[0085] C1: By evaluating the number of particles with a particle size of 0.3 to 0.5 μm before the filter,

[0086] The number of particles with a particle size of 0.3 to 0.5 μm here refers to the number of KCL particles contained in the 0.3 to 0.5 μm measurement range in the particle size measurement range of the particle technology instrument.

[0087] Example 1

[0088] (1) Preparation of an annular filter body: The charged melt-blown nonwoven fabric is pleated to form a continuously bent V-shaped structure, the folded edge height of the V-shaped structure is 25 mm, the adjacent two sides of the V-shaped structure are bonded by a 15 mm long colloid, the distance between the highest part of the colloid and the peak edge of the V-shaped structure is 10 mm, and the two end surfaces parallel to the folded edge of the V-shaped structure are connected by the colloid to form a closed ring;

[0089] (2) Preparation of hard support part: ABS resin material is used to make a support part with a thickness of 2 mm by injection molding;

[0090] (3) Preparation of coarse filter layer: A PA diamond mesh with a wire diameter of 0.16 mm was used, and both ends of the mesh were ultrasonically welded with a weld width of 2.5 mm;

[0091] (4) putting the coarse filter layer prepared in step (3) on the periphery of the annular filter body;

[0092] (5) Use EPDM foam as a flexible sealing part, stamp it into a circular ring, the width from the inner ring to the outer ring is 30 mm, and fit the EPDM foam to the ring-shaped filter body according to the following steps:

[0093] S1. Lay the EPDM foam flat in an assembly mold with an inner ring width of 25 mm and an outer ring width of 6 mm, and place the limiting shaping piece in the middle of the inner ring of the assembly mold;

[0094] S2. Set the operating temperature of the hot pressure-sensitive adhesive to 130°C. After the temperature is reached, spray the adhesive evenly on the surface of the EPDM foam;

[0095] S3. Place one end of the annular filter body having a coarse filter layer on the outer periphery of the annular filter body obtained in step (4) above on the surface of the EPDM cotton coated with glue, and align the inner ring of the annular filter body with the inner ring of the EPDM cotton;

[0096] S4. The other end of the annular filter body in step S3 is pressed down by the shaping and pressing device, and the inner ring of the assembly jig is pressed downward by 3 mm, and the EPDM foam on the outer ring surface of the jig is fitted around one end surface of the annular filter body. The shaping time is 130 seconds, and the EPDM foam at one end is fitted;

[0097] S5. Follow the same method as steps S1 to S4 to complete the bonding of the other end with the EPDM cotton, so that the cotton bonding of both ends of the annular filter body is completed;

[0098] (6) When the filter is in a compressed state, the ABS resin material prepared in step (2) is placed in the hollow part of the filter body. When the filter needs to be installed and used, it is installed at the inner circle position of the upper and lower ends of the filter body to restore the compressed filter, and finally form the cylindrical filter of the present invention. The parameters and physical properties of the filter of the present invention are shown in Table 1 below.

[0099] Example 2

[0100] The preparation process is the same as that of Example 1. The support part is made of PP material, and the coarse filter layer is made of PET material mesh. During filtration recovery, a single support part is used for support. The parameters and physical properties of the filter of the present invention are shown in Table 1 below.

[0101] Example 3

[0102] The preparation process is the same as that of Example 1. The filter is in the shape of a square cylinder, and the supporting component is in the shape of a square ring. The parameters and physical properties of the filter of the present invention are shown in Table 1 below.

[0103] Example 4

[0104] The preparation process is the same as that of Example 3, using a single support portion for support. The parameters and physical properties of the filter of the present invention are shown in Table 1 below.

[0105] Example 5

[0106] The preparation process is the same as that of Example 1, the thickness of the support portion is 8 mm, and the parameters and physical properties of the filter of the present invention are shown in Table 1 below.

[0107] Example 6

[0108] The preparation process is the same as that of Example 1, and the support portion is non-detachable. The parameters and physical properties of the filter of the present invention are shown in Table 1 below.

[0109] Example 7

[0110] The preparation process is the same as that of Example 1. The filter body is incompressible and deformable. The parameters and physical properties of the filter of the present invention are shown in Table 1 below.

[0111] Comparative Example 1

[0112] (1) Preparation of an annular filter body: The charged melt-blown nonwoven fabric is pleated to form a continuously bent V-shaped structure, the folded edge height of the V-shaped structure is 25 mm, the adjacent two sides of the V-shaped structure are bonded by a colloid with a length of 10 mm, the distance between the highest part of the colloid and the peak edge of the V-shaped structure is 15 mm, and the two end surfaces parallel to the folded edge of the V-shaped structure are connected by the colloid to form a closed ring;

[0113] (2) Preparation of hard support part: ABS resin material is used to make a support part with a thickness of 2 mm by injection molding;

[0114] (3) Preparation of coarse filter layer: A PA diamond mesh with a wire diameter of 0.16 mm was used, and both ends of the mesh were ultrasonically welded with a weld width of 2.5 mm;

[0115] (4) putting the coarse filter layer prepared in step (3) on the periphery of the annular filter body;

[0116] (5) Use EPDM foam as a flexible sealing part, stamp it into a circular ring, the width from the inner ring to the outer ring is 30 mm, and fit the EPDM foam to the ring-shaped filter body according to the following steps:

[0117] S1. Lay the EPDM foam flat in an assembly mold with an inner ring width of 25 mm and an outer ring width of 8 mm, and place the limiting shaping piece in the middle of the inner ring of the assembly mold;

[0118] S2. Set the operating temperature of the hot pressure-sensitive adhesive to 130°C. After the temperature is reached, spray the adhesive evenly on the surface of the EPDM foam;

[0119] S3. Place one end of the annular filter body having a coarse filter layer on the outer periphery of the annular filter body obtained in step (4) above on the surface of the EPDM cotton coated with glue, and align the inner ring of the annular filter body with the inner ring of the EPDM cotton;

[0120] S4. The other end of the annular filter body in step S3 is pressed down by the shaping and pressing device, and the inner ring of the assembly jig is pressed downward by 3 mm, and the EPDM foam on the outer ring surface of the jig is fitted around one end surface of the annular filter body. The shaping time is 130 seconds, and the EPDM foam at one end is fitted;

[0121] S5. Follow the same method as steps S1 to S4 to complete the bonding of the other end with the EPDM cotton, so that the cotton bonding of both ends of the annular filter body is completed;

[0122] (6) When the filter is in a compressed state, the ABS resin material obtained in step (2) is placed in the hollow part of the filter body. When the filter needs to be installed and used, it is installed in the inner circle position of the upper and lower ends of the filter body to restore the compressed filter, and finally form a cylindrical filter.

[0123] When the filter is compressed, the colloids on the two adjacent sides of the V-shaped structure break, and the product appearance does not meet the requirements. The performance of the filter is tested in the restored state and the performance is abnormal. The parameters and physical properties of the filter are shown in Table 1 below.

[0124] Comparative Example 2

[0125] The preparation process is the same as that of Comparative Example 1. The length of the colloid on the two adjacent sides of the V-shaped structure is 22.5 mm, and the distance between the highest part of the colloid and the peak edge of the V-shaped structure is 2.5 mm. When the filter is compressed, since the length of the V-shaped connection colloid is too long, the ratio of the colloid length to the height of the folded edge of the V-shaped structure is too large. When the filter is compressed, the adjacent folded edges of the inner filter surface are squeezed against each other, the resistance of the colloid to the folded edge is too large, and the folded edge has wrinkles. The parameters and physical properties of the filter are shown in Table 1 below.

[0126] Comparative Example 3

[0127] The preparation process is the same as that of Comparative Example 1. The length of the colloid is the same as the height of the folded edge. The filter body is difficult to deform. When compressed and deformed, wrinkles appear on the folded edge of the filter. The overall wind resistance of the filter is high. The parameters and physical properties of the filter are shown in Table 1 below.

[0128] Table 1

[0129]

Claims

1. A method for preparing a filter, characterized in that: The following steps are involved: (1) Preparation of an annular filter body: a nonwoven fabric is pleated to form a continuously bent V-shaped structure, and two end surfaces parallel to the folded edge of the V-shaped structure are connected to form a closed ring to obtain an annular filter body, wherein the adjacent two sides of the V-shaped structure are bonded by a colloid, the length of the colloid is 54-70% of the height of the folded edge of the V-shaped structure, and the distance between the highest part of the colloid and the peak edge of the V-shaped structure is 30-46% of the height of the folded edge; (2) Preparation of the sealing portion: punching the bendable sealing portion by a punching device to obtain an annular sealing portion; (3) Preparation of the hard support portion: using synthetic resin for injection molding to obtain a hard support portion with a thickness of 2 to 10 mm; (4) Assembling the sealing part and the annular filter body to obtain a filter, the specific assembly steps are as follows: S1. Place the sealing part in the assembly mold, wherein a limited position shaping component is provided in the middle of the inner ring of the assembly mold, the width of the inner ring is equal to the height of the folded edge of the annular filter body, and the width of the outer ring of the assembly mold is 2 to 10 mm; S2. Spraying the hot pressure-sensitive adhesive on the sealing portion; S3. Place one end of the annular filter body on the surface of the sealing portion after the glue is applied; S4. Pressing the other end of the annular filter body in step S3 downwardly by the pressing device, the sealing portion is fitted with the circumference of the annular filter body; S5. Use the same method as steps S2 to S4 to complete the bonding of the other end sealing part.

2. The method for preparing a filter according to claim 1, characterized in that: Preparation of pre-filter: Make a circle of polyamide mesh or polyester mesh material and connect them to form a pre-filter.

3. The method for preparing the filter according to claim 2, characterized in that: The wire diameter of the pre-filter is 0.15-0.30 mm.

4. The method for preparing a filter according to claim 2, characterized in that: The width of the joint seam of the pre-filter is 2.0-5.0 mm.

5. The method for preparing a filter according to claim 1, characterized in that: The thermal pressure-sensitive adhesive is heated to 120-200° C. in a glue box.

6. The method for preparing a filter according to claim 1, characterized in that: The curing time of the thermal pressure-sensitive adhesive is 60 to 120 seconds.

7. The method for preparing a filter according to claim 1, characterized in that: The inner annular surface in the assembly mold is a retractable annular surface.

8. The method for preparing the filter according to claim 7, characterized in that: The descending height of the inner annular surface is 2 to 8 mm.

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