CN114130128A

CN114130128A - Air filter

Info

Publication number: CN114130128A
Application number: CN202010909347.3A
Authority: CN
Inventors: 贾建东; 杨印景
Original assignee: Hangzhou Kebaite Technology Co ltd
Current assignee: Hangzhou Kebaite Technology Co ltd
Priority date: 2020-09-02
Filing date: 2020-09-02
Publication date: 2022-03-04
Anticipated expiration: 2040-09-02
Also published as: CN114130128B

Abstract

The invention relates to an air filter, which comprises a filter medium and a shell, wherein the shell is provided with a gas inlet and a gas outlet, the gas inlet is communicated with the upstream side of the filter medium, the gas outlet is communicated with the downstream side of the filter medium, the filter medium is folded to form folds, the filter medium comprises a non-woven fabric supporting layer and an adsorptive particle layer, the adsorptive particle layer is placed between the two non-woven fabric supporting layers, the air filter is characterized by also comprising a fiber felt, the fiber felt is bonded with the adsorptive particle layer, the fiber felt comprises a first fiber set and a second fiber set, the length of fibers in the first fiber set is z, the length of fibers in the second fiber set is w, and the z and w satisfy the following conditions: z/w is more than 2 and less than or equal to 50, wherein the value range of z is 30-60 mm. The object of the present invention is to provide an air filter having a high strength filter medium.

Description

Air filter

Technical Field

The invention relates to a filter, in particular to an air filter.

Background

In recent years, air filters have gradually come into production and life. The air filter is a product capable of adsorbing, decomposing or converting various pollutants in air and effectively improving the indoor air cleanliness, and is applied to the fields of household, medical treatment and industry, and the air filters applied to different fields have different filtering requirements. In many industrial plants, when producing precision products, the production plants are usually kept clean, which requires the air entering the clean plants to be filtered, and the environment inside the clean plants must be strictly controlled.

In the patent document publication No. US6024782, a layered gas filtration medium is disclosed, which comprises a binding layer, a substrate and an adsorbent layer, one side of the adsorbent layer being bonded to the binding layer and the other side of the adsorbent layer being bonded to another binding layer, thus repeatedly forming a multilayer structure, wherein the substrate provides a supporting function. This patent only constitutes gas filter medium through bonding layer and adsorbent layer, so can change filter medium's density through the density that sets up the adsorbent layer, and then play the effect of adjusting filter material's pressure drop. However, such a filter medium requires a relatively large amount of adhesive to wet the surface of the adsorbent layer, and the wetted portion no longer has an adsorption effect, which seriously affects the adsorption capacity of the adsorbent layer, and such a filter medium bonded together only by the adhesive is also not high in strength and toughness.

In the patent document publication US6423123, a filter material for fluid media is disclosed, which comprises a carrier layer and an adsorption layer, wherein the adsorption layer is formed from adsorbent particles and molten binder threads, and the adsorption layer is adhered to the carrier layer by the molten binder threads. The filtering material with the structure can firmly adhere the carrier layer and the adsorption layer together without an adhesive, and the melting adhesive wire also has the effects of strengthening and toughening in the filtering medium.

In the prior art, under the condition that the size of a filter shell is fixed, in order to increase the filtering area and reduce the resistance of air filtration, a filter medium is usually folded, but the folding structure has higher requirements on the strength and toughness of the filter medium, and the filter medium made of a high-molecular binder or a glue thread can not meet the strength requirement.

Disclosure of Invention

The object of the present invention is to provide an air filter having a high strength filter medium.

In order to achieve the purpose, the invention adopts the following technical scheme: an air filter comprising a filter medium and a housing, the housing having a gas inlet and a gas outlet, the gas inlet communicating with an upstream side of the filter medium, the gas outlet communicating with a downstream side of the filter medium, the filter medium being folded to form pleats, the filter medium comprising a nonwoven support layer and an adsorptive particle layer, the adsorptive particle layer being placed between two nonwoven support layers, characterized by further comprising a fiber mat bonded to the adsorptive particle layer, the fiber mat containing a first fiber set and a second fiber set, the fibers in the first fiber set having a length z, the fibers in the second fiber set having a length w, z and w satisfying: z/w is more than 2 and less than or equal to 50, wherein the value range of z is 30-60 mm.

The filter medium is folded to form folds, so that the filtering area of the shell of the air filter can be increased under the condition of unchanged size, and the dust holding capacity of the air filter can also be increased. The filter medium comprises a fiber felt, an adsorptive particle layer and a non-woven fabric support layer. So design, when certain department atress of filter media, the fibre in the first fiber collection on the adsorbability granular layer accessible fibrofelt and the fibre in the second fiber collection with stress evenly dispersed on filter media, increase filter media's intensity, fundamentally has overcome filter media's fragility. As shown in the schematic diagram of the fiber reinforcement mechanism of fig. 1, the stress acting on the adsorptive particles 1 transmits the stress dispersion to the other fibers 2 through the bonding points between the fibers 2, and if one of the fibers 2 is broken, the other fibers 2 act as they are without compromising the integrity, thus macroscopically showing an increase in the strength and toughness of the filter medium. Further, the filter media forming the pleats is subjected to bending stress at the bending pleats, as shown in the schematic view of the material bending of fig. 2, the fibers and active particles on the concave side of the filter media are compressed when the filter media is bent, the fibers on the convex side are stretched, and the fibers and active particles of the neutral layer are not stressed. In the present invention, the fibers in the fiber mat are uniformly distributed, and assuming that the bonding points at which the fibers per unit length are bonded to each other are constant, the fibers in the first fiber set having a longer length have more bonding points on the fiber mat than the bonding points of the fibers in the second fiber set. If the fibers in the first fiber set with many bonding points and the fibers in the second fiber set with few bonding points are simultaneously positioned on the protruding side of the folded filter medium, the fibers in the first fiber set are more easily broken due to large stress, so that the adsorptive particle layer falls off, and the adsorptive particle layer is broken in serious conditions. The fibers in the second fiber set positioned on the protruding side of the folded filter medium are less in bonding points, so that the resultant force is small and the fibers are not easy to break; furthermore, the mass of the layer of adsorbent particles bonded to the fibers per unit length is constant, and the mass of the layer of adsorbent particles bonded to the fibers in the first fiber set having a longer length is greater than the mass bonded to the fibers in the second fiber set. These all allow for greater flexibility of the fibers in the second fiber set, which can effectively enhance the strength and toughness of the filter media. As shown in fig. 3, the length relationship between the fibers in the first fiber set and the fibers in the second fiber set is within the range of the length of the fibers in the first fiber set and the fibers in the second fiber set. In the fiber felt, the fibers in the first fiber set with longer length mainly play a role of connecting and fixing the shape of the fiber felt and maintaining a basic frame of the fiber felt, if the length z of the fibers in the first fiber set is less than 30mm, the span of the fibers in the first fiber set in the fiber felt is smaller, the shape of the fiber felt cannot be fixed, and the fiber felt is easy to fall apart at the moment, so that the strength of the filter medium is reduced; if the length z of the fibers in the first fiber set is greater than 60mm, the span of the fibers in the first fiber set in the filter medium is large, the mass of the adsorptive particle layer bonded on the fibers in the first fiber set is large, and the bonding points of the fibers in the first fiber set and other fibers are also large, so that the fibers in the first fiber set are easy to break, the adsorptive particle layer bonded on the fibers is easy to fall off, and the filtering effect of the strength of the filter medium is influenced. Therefore, the length of the fibers in the first fiber set is within the range of z being more than or equal to 30mm and less than or equal to 60 mm. If z/w is less than or equal to 2, namely the length values of the fibers in the first fiber set and the fibers in the second fiber set fall in an open area D defined by z 2w, z 30 and z 60, the length w of the fibers in the second fiber set is too long compared with the fibers in the first fiber set, so that the flexibility of the fibers in the second fiber set in the filter medium is reduced, and the fibers in the filter medium cannot play a role in enhancing; if z/w is greater than 50, that is, the values of the fibers in the first fiber set and the fibers in the second fiber set fall within a closed region C surrounded by z 50w, z 30 and z 60, at this time, the length w of the fibers in the second fiber set is too short relative to the length of the fibers in the first fiber set, and when the filter medium is subjected to a force, the fibers in the second fiber set are easily pulled out from the layer of adsorptive particles, thereby reducing the effect of the fibers in the second fiber set in the filter medium. And if the fibers in the second fiber set are too short, the quantity of the adsorptive particles bonded on the fibers is small, so that the bonding force between the fibers in the second fiber set and the adsorptive particle layer is small, the fibers in the second fiber set are easy to separate from the adsorptive particle layer, and the strength of the filter medium is influenced. Therefore z and w should satisfy: z/w is more than 2 and less than or equal to 50, and the value range of z is between 30 and 60mm, so that the integral framework of the fiber felt can be maintained, and the strength and the filtering effect of the filter medium can be improved.

Further, the length z of the fibers in the first fiber set and the thickness a of the layer of adsorbent particles satisfy: z is more than or equal to 10a +10, and the length w of the fibers in the second fiber set and the thickness a of the adsorptive particle layer satisfy the following condition: w is more than or equal to 3mm and less than or equal to 6a, and the thickness a of the adsorptive particle layer ranges from: a is more than or equal to 0.5mm and less than 5 mm.

Generally, the adsorptive filtration capacity of the filter media is adjusted by adjusting the content of the layer of adsorptive particles. In the present invention, the content of the adsorptive particle layer may be represented by its thickness a. In the filter medium, the fiber mat can not only serve as a layer of bound adsorptive particles, as an attachment carrier therefor, but also as a reinforcing substance for the filter medium. Specifically, the fibers in the first fiber set and the fibers in the second fiber set in the fiber mat have different functional roles. In order to guarantee the whole frame construction of fibrofelt, avoid fibrofelt and adsorptivity particular layer to take place to break away from each other, satisfy between the length z of fibre and the thickness a of adsorptivity particular layer in the first fibre collection: z is more than or equal to 10a + 10. Referring to fig. 4, the length of the fibers in the first fiber set, z, is in the form of a closed area D having a length of 0.5mm or more and a < 5mm, z being equal to or greater than 10a +10, z being equal to 30 and z being equal to 60, relative to the thickness of the absorbent particle layer. So, fibre in first fibre collection has certain space span in the fibrofelt that adheres to there is the adsorptivity grained layer, can fix the adsorptivity grained layer on the whole thickness direction of fibrofelt, guarantees the evenly distributed of adsorptivity grained layer on the fibrofelt, keeps the whole frame construction of fibrofelt that bonds there is the adsorptivity grained layer. In order to guarantee the intensity of filter medium, guarantee that the fibre felt who adheres to the adsorptivity grained layer can not break when fold department or atress, satisfy between the length w of fibre and the thickness a of adsorptivity grained layer in the second fiber set: w is more than or equal to 3mm and less than or equal to 6 a. As shown in FIG. 5, the length of the fibers in the second fiber set, w, is plotted in the shaded area relative to the thickness of the adsorbent particle layer. In the present invention, if the length w of the fibers in the second fiber set is less than 3mm, the contact area between the fibers in the second fiber set and the layer of adsorptive particles is too small, the layer of adsorptive particles bonded to the fibers in the second fiber set is small, and the adhesion between the fibers and the layer of adsorptive particles is small. If the length w of the fibers in the second fiber set is greater than 6a, an excessive layer of adsorptive particles will adhere to the fibers in the second fiber set, reducing the flexibility of the fibers in the second fiber set, and the fibers in the second fiber set cannot disperse the stress on the filter medium by slipping when the filter medium is stressed or bent. Therefore, when w is more than or equal to 3mm and less than or equal to 6a, the fibers in the second fiber set have enough flexibility in the filter medium with a certain thickness, the strength of the filter medium can be enhanced, and the filtering effect of the filter medium is ensured. In order to ensure that the filter medium has good filtering efficiency and filtering effect, the thickness a of the adsorptive particle layer is more than or equal to 0.5 mm; however, if the thickness a of the adsorptive particle layer is larger than or equal to 5mm, the filtering effect of the filtering medium is not obviously improved, but the weight of the filtering medium is too large, so that the overall weight of the air filter is increased integrally, and the actual production and utilization are not facilitated. The thickness a of the adsorptive particle layer is within the range of a being more than or equal to 0.5mm and less than 5mm, so that the requirement of adsorption and filtration of the air filter can be met, the weight increase of the air filter caused by the overlarge thickness of the adsorptive particle layer can be avoided, and the production cost is saved.

Further, the weight ratio of the fiber mat to the filter medium is in the range of 2% to 5%, and the weight ratio of the fibers in the second fiber set to the fiber mat is in the range of 10% to 50%.

In the invention, the fiber felt is used as a carrier of the adsorptive particle layer, fixes the adsorptive particle layer with adsorptive and filtering performances in the filter medium, and is also used as a reinforcing material of the filter medium, so that the strength and the toughness of the filter medium are increased. If the weight ratio of the fiber felt to the filter medium is less than 2%, the fiber felt cannot bear the adsorptive particle layer and is fixed on the non-woven fabric support layer, and the reinforcing and toughening effects of the fiber felt are not obvious; if the weight ratio of the fiber mat to the filter medium is greater than 5%, unnecessary waste may be caused, the overall weight of the filter medium may be increased, and the excessive fiber mat may also increase the filtration resistance of the filter medium. Only when the weight ratio of the fiber felt to the filter medium is within the range of 2-5%, the function of the fiber felt as a carrier of an adsorptive particle layer in the filter medium and the reinforcing and toughening effects of the fiber felt in the filter medium can be ensured, and the manufacturing cost of the filter medium can be saved. Furthermore, in the fiber felt, the fibers in the second fiber set mainly play a role in enhancing and toughening due to the flexibility of the fibers, and in order to ensure the exertion of the functions of the fibers, the weight ratio of the fibers in the second fiber set to the fiber felt is within a range of 10-50%.

Further, the fibers in the second fiber set are aligned in an order in a direction perpendicular to the pleats to form the anisotropic fiber mat.

Because the fibers in the second fiber set mainly play a role in strengthening and toughening, in order to avoid the filter medium from being broken due to bending stress generated at the folds of the filter medium, the fibers in the second fiber set are orderly arranged in the direction perpendicular to the folds, so the fibers in the second fiber set are taken as main stress action objects at the folds, and the function of strengthening and toughening can be better played. It should be noted that the above-mentioned ordered arrangement means that at least 60-90% by weight of the fibers in the second fiber set of the fiber mat enclose an angle with the pleats in the range of 45-90, and this explanation applies throughout.

Further, the layer of adsorbent particles comprises active particles, and the ratio of the diameter of the fibers in the first fiber set and/or the fibers in the second fiber set to the diameter d of the active particles is below 1/10.

By means of the design, the fibers in the first fiber set and/or the fibers in the second fiber set are only contacted with the active particles in a very small space range, so that the adsorption and filtration functions of the active particles are not influenced by the existence of the fibers in the first fiber set and/or the fibers in the second fiber set, the active particles can be distributed in a fiber felt in a three-dimensional mode, and the filtration effect of the filter medium is guaranteed.

Further, the diameter d of the active particles and the length z of the fibers in the first fiber set satisfy: z/d is more than or equal to 50 and less than or equal to 500, and the diameter d of the active particles and the length w of the fibers in the second fiber set satisfy that: w/d is more than or equal to 9 and less than or equal to 200.

The diameter d of the active particles and the length z of the fibers in the first fiber set satisfy: z/d is more than or equal to 50 and less than or equal to 500, and d and the length w of the fibers in the second fiber set satisfy that: w/d is more than or equal to 9 and less than or equal to 200. The active particles are bonded on the fibers in the first fiber set and the fibers in the second fiber set, if z/d is less than 50 and w/d is less than 9, under the condition that the diameter of the active particles is determined, the length of the fibers in the first fiber set and the fibers in the second fiber set is smaller than the diameter of the active particles, and the fibers in the first fiber set serve as a basic frame of the fiber mat and mainly play a role in connection and fixation in the fiber mat. If the length of the fibers in the first fiber set is too short, the firmness of the fiber mat is low, and the fiber mat is easy to break apart under stress. The fibers in the second fiber set can disperse the stress on the filter medium through relative sliding due to the flexibility of the fibers, so that the strength of the filter medium is increased. If the length of the fibers in the second fiber set is too short, the contact area between the fibers in the second fiber set and the adsorptive particle layer is too small, the active particles bonded on the fibers in the second fiber set are too few, and when the filter medium is stressed, the fibers in the second fiber set are easily pulled out from the adsorptive particle layer, so that the effect of the fibers in the second fiber set in the filter medium is greatly reduced; if z/d is greater than 500 and w/d is greater than 200, the length of the fibers in the first fiber set and the length of the fibers in the second fiber set are too long, which affects the strength and toughness of the filter medium. Specifically, when the length of the fibers in the first fiber set is too long, the span of the fibers in the first fiber set in the filter medium is too long, the fibers appear in a plurality of pleats and can be subjected to large bending stress, and the fibers in the first fiber set are easy to break, so that the strength of the filter medium is affected; and when the length of the fiber in the second fiber set is too long, the number of bonding points between the fiber and the adsorptive particle layer and between the fiber and other fibers is large, and the flexibility of the fiber in the second fiber set is reduced when the filter medium is stressed, so that the stress borne by the filter medium cannot be dispersed by the slippage of the fiber in the second fiber set, and the filter medium is easy to break.

Further, at least one of the fibers in the first fiber set and the fibers in the second fiber set is a composite fiber, the composite fiber comprises a first component and a second component, the melting point of the material of the first component is lower than that of the material of the second component, the fiber felt and the adsorptive particle layer are bonded together by the first component through thermal fusion, and the fiber felt and the non-woven fabric support layer are bonded together by the first component through thermal fusion.

At least one of the fibers in the first fiber set and the fibers in the second fiber set is a composite fiber, the melting point of the first component of the composite fiber is lower than that of the second component, and the fiber felt, the adsorption particle layer and the non-woven fabric support layer are bonded together by the first component in a thermal fusion mode. By the design, the use of high polymer bonding materials is reduced or avoided while the bonding strength of the filter medium is ensured. Moreover, the bonding mode can make the fixed of adsorptivity grained layer more stable, also can not block up the appearance of phenomenons such as adsorptivity grained layer because of the infiltration of polymer bonding material, guarantees the filtering quality of product.

Further, the composite fiber is a concentric sheath-core structure, and the first component surrounds the second component.

The composite fiber is a concentric sheath-core structure with a low melting first component surrounding a high melting second component. So design, when the fibrofelt was heated, first component melted and made the fibrofelt produce the bonding effect, and the existence of fibrofelt can continue to be guaranteed to the second component, provides for the adsorptivity particle layer to adhere to on the fibrofelt and depends on. Moreover, when the composite fiber with the concentric sheath-core structure is heated, the melting of the first component can be ensured to be more uniform and sufficient, the bonding effect of the fiber felt is ensured, and the overall bonding strength of the filter medium is further ensured.

Further, the material of the first component is selected from one of polyethylene and polypropylene, and the material of the second component is selected from one of polyethylene terephthalate, polytrimethylene terephthalate and polybutylene terephthalate.

By the selection, the characteristic that the fiber felt generates viscosity when being heated can be realized, and the forming processing of the composite fiber is facilitated. Moreover, the raw materials are low in price, so that the product cost can be reduced.

Further, the non-woven fabric support layer comprises sheath-core composite fibers, and the sheath component of the sheath-core composite fibers is lower than the melting point of the core component of the sheath-core composite fibers by more than 20 ℃; or the non-woven fabric support layer comprises low-melting-point fibers and high-melting-point fibers, and the melting point of the low-melting-point fibers is lower than that of the high-melting-point fibers by more than 20 ℃.

So design for the non-woven fabrics supporting layer keeps under its stable in structure unchangeable condition after the heating, has the cohesiveness again, bonds fibrofelt and adsorptivity grained layer on the non-woven fabrics supporting layer, increases the holistic cohesive strength of filter media, avoids fibrofelt and adsorptivity grained layer to drop from filter media.

Further, the layer of adsorbent particles comprises active particles comprising one or more of activated carbon, ion exchange resin, zeolite, virucidal agent, biocidal agent, clay, organometallic catalyst.

So design, the kind of active particle can satisfy different filtration demands, realizes air cleaner's functional diversity and filter effect.

In another aspect, the present invention provides a method for manufacturing a filter medium, comprising the steps of:

s1: uniformly scattering a first adsorptive particle layer on the surface of the non-woven fabric support layer;

s2: laying a fiber felt on the surface of the first adsorptive particle layer, and scattering a second adsorptive particle layer on the surface of the fiber felt to form a semi-finished product;

the fiber felt comprises a first fiber set and a second fiber set, wherein the lengths of the fibers in the first fiber set are recorded as z, the lengths of the fibers in the second fiber set are recorded as w, and z and w satisfy the following conditions: z/w is more than 2 and less than or equal to 50, wherein the value range of z is 30-60 mm;

s3: laying a non-woven fabric supporting layer on the second adsorptive particle layer, and performing hot-pressing processing through a hot roller at the temperature of 200-220 ℃;

s4: cooling to obtain the filter medium.

When the filter medium is prepared, a first adsorptive particle layer is firstly spread on a non-woven fabric supporting layer, then a fiber felt is paved on the first adsorptive particle layer, a second adsorptive particle layer is spread on the fiber felt to form a semi-finished product, finally the non-woven fabric supporting layer is paved on the semi-finished product, and the filter medium is formed through hot roller processing. In order to ensure the strength of the filter medium and avoid the filter medium from breaking when being stressed, the fiber felt comprises a first fiber set and a second fiber set, and the length z of the fibers in the first fiber set and the length w of the fibers in the second fiber set satisfy the following conditions: z/w is more than 2 and less than or equal to 50, wherein the value range of z is 30-60 mm. Therefore, the fibers in the first fiber set can play a role in connecting and fixing the overall shape and structure of the fiber mat, and meanwhile, the fibers in the second fiber set are used as main reinforcing and toughening fibers in the filter medium, so that the flexibility is sufficient, and the stress on the filter medium can be dispersed through relative sliding.

Further, the first and/or second layer of adsorbent particles comprises a gum powder.

The first and/or second absorbent particulate layers have a glue powder therein. So design, at the in-process of heating manufacturing filter medium, the rubber powder melts and produces viscidity, bonds first adsorbability grained layer and second adsorbability grained layer to the fibre felt to rely on the adhesive effect of rubber powder, further bond the fibre felt that has the adsorbability grained layer to the non-woven fabrics supporting layer, form filter medium.

Further, the step S1 comprises preheating to 100-150 ℃, the step S2 comprises preheating to 180-200 ℃, and the preheating time of S1 and S2 is within the range of 5-10 min.

Both the step S1 and the step S2 include preheating. So design, can guarantee that non-woven fabrics supporting layer, each adsorptivity grained layer and fibrofelt can the thermally equivalent in each step that forms semi-manufactured goods, and then obtain the unanimous filter medium of homogeneity. And the preheating function also ensures that the rubber powder can completely play a role to generate viscosity, and the first adsorptive particle layer and the second adsorptive particle layer are attached to the fiber felt, so that the uniformity of the filter medium and the bonding strength of each component in the filter medium are ensured. And the preheating time of S1 and S2 is within the range of 5-10 min. By the design, the rubber powder is ensured to generate viscosity, and the influence on the formation of a semi-finished product due to overlong preheating time is prevented. The preheating temperatures of the S1 and S2 steps are different, and the preheating temperature of the S1 step is lower than that of the S2 step, so as to prevent the temperature from adversely affecting the manufacture of the filter medium in the subsequent process steps.

Further, after the semi-finished product is formed in S2, a third layer of adsorptive particles is laid, which includes rubber powder.

And laying a third adsorptive particle layer on the semi-finished product, wherein the third adsorptive particle layer comprises rubber powder. So design, can be in increase filter media adsorptivity grained layer content to when increase filter media adsorbs the filter effect, can guarantee the cohesive strength of filter media's intensity again.

Further, the step of S2 may be repeated a plurality of times.

So, can be when guaranteeing filter medium bonding strength, increase the thickness of the adsorptivity grained layer in the filter medium, increase filter medium's adsorption filtration effect.

Further, there is a Sa step between the steps S2 and S3,

sa: and melt-blowing the glue blocks into glue threads onto the fiber felt through a hot melt glue machine, wherein the diameter of the glue threads is 10-50 mu m, the glue blocks are selected from one or more of polyolefin, EVA and polyurethane, and the heating temperature of the S3 step is 100-160 ℃.

In this way, the bonding strength of the filter medium is provided by the viscosity of the fiber felt and the glue thread, and the bonding effect of the filter medium is increased.

Drawings

The invention will be further described with reference to the accompanying drawings in which:

FIG. 1 is a schematic illustration of a fiber reinforcement mechanism;

FIG. 2 is a schematic view of material bending;

FIG. 3 is a relationship of lengths of fibers in a first fiber set and fibers in a second fiber set;

FIG. 4 is a graph of fiber length versus thickness of an adsorbent particle layer in a first fiber set;

FIG. 5 is a graph of the relationship between the length of the fibers in the second fiber set and the thickness of the adsorbent particle layer;

FIG. 6 is a schematic view of an air filter according to a first embodiment of the present invention;

FIG. 7 is a schematic illustration of a longitudinal cross-section of a filter media according to a first embodiment of the present invention;

FIG. 8 is a schematic cross-sectional view of a filter media according to a first embodiment of the present invention;

FIG. 9 is a schematic cross-sectional view of a composite fiber according to an embodiment of the present invention.

Detailed Description

In order that the above objects, features and advantages of the present invention can be more clearly understood, a more particular description of the invention will be rendered by reference to the appended drawings. It should be noted that the embodiments and features of the embodiments of the present application may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced in other ways than those specifically described herein, and therefore the scope of the present invention is not limited by the specific embodiments disclosed below.

As shown in fig. 6, a schematic view of an air filter, the air to be filtered enters the air filter 15 through the air inlet 16, and is discharged through the air outlet 17 after being sufficiently contacted with the filter medium 3. As shown in the schematic view of the longitudinal section of the filter medium in fig. 7, the filter medium 3 is folded to form pleats 10 in order to increase the contact area between the filter medium 3 and the air, reduce the resistance during filtration, and increase the dust holding capacity of the air filter. As shown in fig. 8, the filter medium 3 includes a non-woven fabric support layer 4 and an adsorptive particle layer 5, the adsorptive particle layer 5 is disposed between two non-woven fabric support layers 4 to prevent the adsorptive particle layer 5 from falling off during use, and the adsorptive particle layer 5 has active particles therein to adsorb and filter impurities in the air. To increase the strength and toughness of the filter media 3, a fiber mat 6 is also included in the filter media 3. In order to be able to show the structure of the filter medium 3 more clearly, fig. 8 is of exaggerated composition, the actual fibre mat 6 being evenly distributed with active particles throughout its thickness, the actual structure being shown in fig. 7. As can be seen from the schematic diagram of the fiber reinforcement mechanism in fig. 1, when the filter medium 3 is stressed, the stress acting on the adsorptive particle layer 5 is transmitted to other fibers 2 through the fibers 2, and the stress on the filter medium 3 is dispersed, so that the strength and toughness of the filter medium 3 are increased. The fiber mat 6 may also serve as a carrier for the adsorptive particle layer 5, and firmly fix the adsorptive particle layer 5 in the filter medium 3.

The fiber mat 6 of the filter medium 3 has a first fiber set and a second fiber set, the length z of the fibers in the first fiber set and the length w of the fibers in the second fiber set corresponding to: z/w is more than 2 and less than or equal to 50, wherein the value range of z is 30-60 mm. In filter media 3 folded to form pleats 10, the fibers on the side of the pleats 10 from which they protrude are stretched. The fibers in the second fiber set have good flexibility due to the low number of layers of absorbent particles 5 adhered thereto and the low number of bonding points with other fibers in the fiber mat 6. When the fibers in the second fiber set are positioned on the protruding side of the pleat 10, the fibers in the second fiber set can avoid the phenomenon of force fracture by relative sliding, and the strength of the filter medium 3 is ensured. The fibers in the first fiber group serve as a connecting and fixing element in the fiber mat 6 due to the long spatial span.

A (100X100) mm filter medium was used as a test sample, and the nonwoven fabric support layer, the adsorptive particle layer and the fiber mat were peeled off from each other. To prevent the stripping process from breaking the fibers in the fiber mat, the test sample may be heated to melt the cementitious material in the sample. And measuring the fiber length in the sample by using a standard vertical ruler after stripping, and classifying and summarizing the fiber length to obtain the rule of the fiber length in the sample fibrofelt. The fiber mat comprises a first fiber set and a second fiber set, the length of the fibers in the first fiber set is z, the length of the fibers in the second fiber set is w, and z and w satisfy: z/w is more than 2 and less than or equal to 50, wherein the value range of z is 30-60 mm.

To further verify the effect of the length of the fibers in the first fiber set and the second fiber set on the strength of the filter media 3, the peel strength of the nonwoven support layer and the fiber mat was obtained as measured by the bond strength of the coating layer of standard HG/T3052-. The filtration efficiency and filtration resistance of the filter media were tested using an AMC tester according to the ASHRAE 145.1 standard. Wherein the test flow is 29.3L/min, and the test area is 26.4cm²And testing the filtering effect of the filtering medium to obtain the data, wherein the specific results are shown in the following table 1:

s1: scattering a first adsorptive particle layer on the surface of the non-woven fabric supporting layer;

s2: spreading the fiber felt on the surface of the first adsorptive particle layer, and scattering a second adsorptive particle layer on the surface of the fiber felt to form a semi-finished product;

the fiber felt comprises a first fiber set and a second fiber set which are different in length, wherein the length z of the fibers in the first fiber set is 30-60mm, and the length w of the fibers in the second fiber set is 0.6-1.2 mm;

s4: after cooling, the sample of example 1 was obtained.

Varying the lengths of the fibers in the first fiber set and the fibers in the second fiber set in the fiber mat resulted in different examples and comparative examples, as specified in table 1 below. And examples 1-5 and comparative examples 1-2 are identical except that the length of the fibers in the first fiber set and the length of the fibers in the second fiber set are different.

TABLE 1 Effect of the Length ratios of the fibers in the first and second fiber sets on Filter media

The fracture that adsorbability granular layer took place easily at the fold department of filter media, and the fibrofelt can be effectual intensity and the toughness that strengthens adsorbability granular layer this moment, and first fiber set internal fiber and second fiber set internal fiber have different functions in filter media moreover. The second fiber in the fiber set with proper length can disperse the bending stress of the filter medium by mutual sliding because of good flexibility, and the adsorptive particle layer is firmly fixed in the filter medium, so the filtering efficiency of the filter medium is not greatly changed before and after folding. And because the flexibility of the fiber in the second fiber set and the connection and fixation of the fiber in the first fiber set, the bonding strength of the non-woven fabric support layer and the fiber felt of the filter medium can be effectively improved. When the values of z and w fall into the region E, the fibers in the second fiber set have better flexibility in the folded filter medium, so that the filter effect of the filter medium is ensured, but if the length of the fibers in the second fiber set is too short, the fibers in the second fiber set are easily pulled out after the filter medium is stressed or folded, and the effect is lost. Thus example 1 has the greatest difference in filtration efficiency before and after folding. The second fiber set of examples 1-3 had shorter fiber lengths and therefore the filtration efficiency after folding was less than that of example 4; however, if the length of the fibers in the first fiber set and the length of the fibers in the second fiber set fall in the region D, as in comparative example 1, the length of the fibers in the second fiber set is too large compared to the fibers in the first fiber set, which affects the flexibility of the fibers in the second fiber set, and the fibers in the second fiber set at the folds are easily broken, so that the active particles fall off, and the filtering effect is affected. Similarly, if the values of the lengths of the fibers in the first fiber set and the second fiber set fall in the region C, as in comparative example 2, the length of the fibers in the second fiber set is too small, the fibers in the second fiber set are easily pulled out from the adsorptive particle layer, the active particles are easily dropped off when the filter medium is folded, the filtering effect of the filter medium is affected, and the bonding effect of the fiber felt and the non-woven fabric support layer is not good.

The thickness a of the layer of adsorbent particles 5 and the length z of the fibers in the first collection of fibers satisfy: z is more than or equal to 10a +10, namely, the thickness a of the adsorption particle layer 5 and the length z of the fibers in the first fiber set are in the area D shown in figure 4, and the length w of the fibers in the second fiber set and the thickness a of the adsorption particle layer 5 satisfy the following conditions: w is more than or equal to 3mm and less than or equal to 6a, and the length w of the fibers in the second fiber set is within the shaded part shown in figure 4. So can guarantee its intensity when guaranteeing filter medium filter effect again. In order to ensure that the filter medium 3 has good filtering efficiency and filtering effect, the thickness a of the adsorptive particle layer is more than or equal to 0.5 mm; however, if the thickness a of the adsorptive particle layer is not less than 5mm, the weight of the filter medium 3 becomes too large, and the overall weight of the air filter increases. Only when the thickness of the adsorptive particle layer is more than or equal to 0.5mm and less than 5mm, the filtering effect and the filtering efficiency of the air filter can be ensured, and the lightness of the air filter is also ensured. When the length z of the fibers in the first fiber set is less than 10a +10, the fibers in the first fiber set have small span in the filter medium 3, cannot play a role in connection and fixation, and are easy to loose and break when the filter medium 3 is stressed. Similarly, when the length w of the second fiber set is less than 3mm, the layer 5 of adsorptive particles adhered to the fibers in the second fiber set is very few, and the bonding points between the fibers in the second fiber set and other fibers are also very few, so that the fibers in the second fiber set are easy to pull out when the filter medium 3 is stressed, and the strength of the filter medium 3 is seriously affected; if the length w of the fibers in the second fiber set is greater than 6a, the length of the fibers in the second fiber set is too long, which affects the flexibility of the fibers in the second fiber set, and when the filter medium 3 is stressed, the fibers in the second fiber set cannot disperse and transfer stress through relative movement, which affects the strength of the filter medium 3.

In order to further verify the influence of the relationship between the lengths of the fibers in the first fiber set and the fibers in the second fiber set and the thickness of the adsorptive particle layer on the filter medium, the test method is specified according to HG/T3052-2008, and the data of the bonding performance are obtained; the filtration efficiency and filtration resistance of the filter media were tested using an AMC tester according to the ASHRAE 145.1 standard. Wherein the test flow is 29.3L/min, and the test area is 26.4cm²And testing the filtering effect of the filtering medium to obtain the data, wherein the specific results are shown in the following table 2:

TABLE 2 influence of fiber length on thickness of adsorptive particle layer on filter media

The manufacturing process of each example and comparative example in table 2 is detailed in table 3 below.

The thickness of the adsorptive particle layer influences the filtering efficiency of the filtering medium, and when the thickness a of the adsorptive particle layer is less than 0.5mm, the filtering efficiency of the filtering medium is too low; when a is more than or equal to 5mm, the influence of the thickness of the adsorption particle layer on the filtering efficiency of the filtering medium is not obvious, and the cost of the filtering medium is increased due to the excessive adsorption particle layer. When the length of the fibers in the second collection is too small, in comparative example 8, the bonding of the fibers in the second collection to the active particles and the bonding of the fibers in the second collection to other fibers on the fiber mat are easily broken when the filter medium is subjected to a force, resulting in a decrease in the bonding strength. In addition, the fibers in the second shorter fiber set are also easy to cause uneven distribution of active particles, so that the filtering effect is influenced; if the length of the fibers in the first fiber set is too long, namely, in comparative example 5, the length of the fibers in the first fiber set is too long, the span of the fibers in the first fiber set in the filter medium is large, excessive active particles are bonded on the fibers, and the bonding points between the fibers and other fibers are too large, so that when the filter medium is folded to form wrinkles or stressed, the fibers in the first fiber set are subjected to large stress, and are easily broken, so that the active particles fall off, and the filtration efficiency of the filter medium is affected. The filtration efficiency of comparative examples 3-8 was generally inferior to that of examples 5-6.

When the fiber mat 6 is used as the reinforcing fiber of the filter medium 3, the reinforcing effect thereof is related to the content of the fiber mat 6. When the weight ratio of the fiber mat 6 to the filter medium 3 is less than 2%, the reinforcing effect of the fiber mat 6 is not significant. Moreover, the layer of absorbent particles 5 cannot be carried because the content of the fiber mat 6 is too small; however, if the fiber mat 6 accounts for more than 5% by weight of the filter medium 3, the content of the fiber mat 6 becomes excessive, resulting in an excessive weight of the filter medium 3. Moreover, the excess fiber mat 6 also affects the air permeability of the filter medium 3.

The fibers in the second fiber set mainly play a role in reinforcing and toughening due to the flexibility, and in order to ensure the function and ensure the connection and fixation of the fibers in the first fiber set, thereby ensuring the structural shape stability of the filter medium 3, the weight ratio of the fibers in the second fiber set to the fiber felt 6 is within the range of 10-50%.

The fibers in the second fiber set are aligned in a direction perpendicular to the pleats 10 to form an anisotropic fiber mat 6. In this manner, the strength and toughness of the filter media 3 in the pleats 10 may be ensured due to the flexibility and ease of movement of the fibers within the second fiber set.

In the present invention, the diameter of the fibers in the first set of fibers and/or the second set of fibers is at least 10 times smaller than the diameter d of the active particles. This ensures that the fibres in the first and/or second fibre set actually only come into contact with the active particles in a very small spatial extent, avoiding that the fibres in the first and second fibre set have an influence on the adsorption properties of the active particles. In order to ensure the strength and the filtering effect of the filter medium 3, the length z of the fibers in the first fiber set in comparison with the diameter d of the active particles satisfies: z/d is more than or equal to 50 and less than or equal to 500, and the length w of the fibers in the second fiber set compared with the diameter d of the active particles satisfies: w/d is more than or equal to 9 and less than or equal to 200. If z/d is less than 50 and w/d is less than 50, that is, the lengths of the fibers in the first fiber set and the fibers in the second fiber set are too short compared with the diameters of the active particles, the fibers in the first fiber set serve as a basic frame of the fiber mat 6 and mainly play a role of connection and fixation in the fiber mat 6, if the fibers in the first fiber set are too short, the fiber mat 6 is easily scattered, so that the strength of the filter medium is too low, and if the lengths of the fibers in the second fiber set are too short, the contact area between the fibers in the second fiber set and the adsorptive particle layer 5 is too small, the active particles bonded on the fibers in the second fiber set are too few, and when the filter medium 3 is stressed, the fibers in the second fiber set are easily pulled out from the adsorptive particle layer 5, so that the role of the fibers in the filter medium 3 in the second fiber set is greatly reduced. Moreover, the number of adsorptive particle layers 5 bonded per unit length between the fibers in the first fiber set and the fibers in the second fiber set is also small, so that the number of adsorptive particle layers 5 per unit area of the filter medium 3 is too small, and the filtration efficiency is affected; if z/d is more than 500 and w/d is more than 200, the length of the fibers in the first fiber set and the length of the fibers in the second fiber set are too long, at this time, too many adsorptive particle layers 5 are bonded on the fibers in the second fiber set, which affects the flexibility of the fibers in the second fiber set, and the fibers in the first fiber set with too long length are subjected to larger resultant force, which is easy to break, and affects the strength and the filtering effect of the filter medium.

In order to secure the bonding strength of the filter medium 3, as shown in the schematic cross-sectional view of the composite fiber of fig. 8, the fibers in the first fiber set are the composite fibers 7 of a concentric sheath-core type structure, the composite fibers 7 have a first component 9 and a second component 8, the melting point of the first component 9 is lower than that of the second component 8, and the first component 9 wraps the second component 8. When the composite fiber 2 is heated, the first component 9 melts to generate viscosity, and meanwhile, the second component 8 can still keep the structure and the performance unaffected. The tackiness created by the first component 9 bonds the layer of absorbent particles 5 and the nonwoven support layer 4 to the fiber mat 6. Therefore, the bonding strength of the filter medium 3 can be ensured, the use of the polymer bonding material is reduced, and the influence of the polymer bonding material on the filter medium 3 is avoided. But also saves the production and manufacturing costs of the filter medium 3. Moreover, when the composite fiber 2 with the concentric sheath-core structure is heated, the melting of the first component 9 can be ensured to be more uniform and sufficient, the bonding effect of the fiber felt 6 is ensured, and the overall strength of the filter medium 3 is further ensured.

The material of the first component 9 is selected from one of polyethylene and polypropylene, and the material of the second component 8 is selected from one of polyethylene terephthalate, polytrimethylene terephthalate and polybutylene terephthalate. These raw materials are inexpensive and easy to machine and form, and can reduce the cost of the fiber mat 6.

In order to further ensure the bonding strength of the filter medium 3 and prevent the fiber felt 6 and the adsorptive particle layer 5 from falling off when the filter medium 3 is stressed, the non-woven fabric support layer 4 comprises sheath-core composite fibers, and the melting point of the sheath layer of the sheath-core composite fibers is at least 20 ℃ lower than that of the core layer material. As such, when the filter medium 3 is heated, the skin layer of the nonwoven fabric support layer 4 melts to generate tackiness, bonding the fiber mat 6 and the layer of adsorptive particles 5 to the nonwoven fabric support layer 4. At this time, the adhesive strength of the filter medium 3 is provided by the tackiness of the fiber mat 6 and the non-woven fabric support layer 4, ensuring the adhesive strength of the filter medium 3. It will be appreciated by those skilled in the art that the sheath-core composite fibers of the nonwoven fabric support layer 4 may be made of the same material as the composite fibers 2 or may be made of different materials.

The active particles include one or more of activated carbon, ion exchange resins, zeolites, virucides, biocides, clays, organometallic catalysts. Can satisfy different filtration demands, when realizing air cleaner's functional diversity and filter effect, have ability greatly reduced manufacturing cost.

A method of filtering media comprising the steps of:

the fiber mat comprises a first fiber set and a second fiber set, the fibers in the first fiber set having a length z of 60-80mm, the fibers in the second fiber set having a length w of 40-55mm, and the layer of adsorbent particles having a thickness a of 4 mm;

s4: and cooled to obtain the sample of comparative example 3.

Varying parameters of the length z of the fibers in the first fiber set, the length w of the fibers in the second fiber set, and the thickness a of the layer of absorbent particles in the fiber mat, using the same starting materials as in comparative example 3, resulted in different examples 5-6 and comparative examples 3-8, as detailed in table 3 below:

TABLE 3 different filter media

The step S1 includes preheating at 100-150 ℃ for 5-10 min, and the step S2 includes preheating at 180-200 ℃ for 5-10 min. So, in follow-up step, guarantee to produce sticky rubber powder can be heated evenly because of the heating effect, and then guarantee adhesive strength between adsorptivity grained layer, fibrofelt and the non-woven fabrics supporting layer. In order to increase the filter adsorption effect of the filter medium 3, a third layer of adsorptive particles is laid in the filter medium 3. Meanwhile, in order to ensure the bonding strength of the adsorptive particle layer 5 in the filter medium 3, the third adsorptive particle layer contains rubber powder.

The step of S2 may be repeated multiple times. So, can be when guaranteeing filter medium bonding strength, increase the thickness of the adsorptivity grained layer in the filter medium, increase filter medium's adsorption filtration effect. And there is a Sa step between the steps S2 and S3,

sa: and melt-blowing the glue blocks into glue threads onto the fiber felt through a hot melt glue machine, wherein the diameter of the glue threads is 10-50 mu m, the glue blocks are selected from one or more of polyolefin, EVA and polyurethane, and the heating temperature of the S3 step is 100-160 ℃. In this way, the bonding strength of the filter medium is provided by the viscosity of the fiber felt and the glue thread, and the bonding effect of the filter medium is increased.

Example two:

compared with the first embodiment, the present embodiment is different in that the nonwoven fabric support layer 4 has low-melting point fibers and high-melting point fibers therein, and the low-melting point fibers have a melting point 20 ℃ lower than that of the high-melting point fibers. As such, when the filter media 3 is heated, the low melt fibers melt to create a tack that bonds the layer of adsorbent particles 5 to the fiber mat 6, which in turn bonds the fiber mat 6 to the nonwoven support layer 4. At this time, the nonwoven fabric support layer 4 can maintain its frame due to the presence of the high-melting-point fibers, and the fiber mat 6 and the adsorptive particle layer 5 are wrapped in the nonwoven fabric support layer 4.

While the preferred embodiments of the present invention have been illustrated and described in detail, it should be understood that various changes and modifications of the invention can be effected therein by those skilled in the art after reading the above teachings of the invention. Such equivalents are intended to fall within the scope of the claims appended hereto.

Claims

1. An air filter comprising a filter medium and a housing, the housing having a gas inlet and a gas outlet, the gas inlet communicating with an upstream side of the filter medium, the gas outlet communicating with a downstream side of the filter medium, the filter medium being folded to form pleats, the filter medium comprising a nonwoven support layer and an adsorptive particle layer, the adsorptive particle layer being placed between two nonwoven support layers, characterized by further comprising a fiber mat bonded to the adsorptive particle layer, the fiber mat containing a first fiber set and a second fiber set, the fibers in the first fiber set having a length z, the fibers in the second fiber set having a length w, z and w satisfying: z/w is more than 2 and less than or equal to 50, wherein the value range of z is 30-60 mm.

2. The air filter of claim 1, having a length z of fibers within the first collection of fibers and a thickness a of the layer of adsorbent particles such that: z is more than or equal to 10a +10, and the length w of the fibers in the second fiber set and the thickness a of the adsorptive particle layer satisfy the following condition: w is more than or equal to 3mm and less than or equal to 6a, and the thickness a of the adsorptive particle layer ranges from: a is more than or equal to 0.5mm and less than 5 mm.

3. The air filter of claim 2, wherein the weight ratio of the fiber mat to the filter media is in the range of 2% to 5%, and the weight ratio of the fibers in the second fiber set to the fiber mat is in the range of 10% to 50%.

4. The air filter of claim 2, wherein the fibers in the second fiber set are aligned in an order oriented perpendicular to the pleats to form an anisotropic fiber mat.

5. The air filter of claim 1, wherein the layer of adsorptive particles comprises active particles, and wherein the ratio of the diameter of the fibers in the first and/or second fiber sets to the diameter d of the active particles is below 1/10.

6. The air filter of claim 5, wherein a diameter d of the active particles and a length z of the fibers in the first fiber set satisfy: z/d is more than or equal to 50 and less than or equal to 500, and the diameter d of the active particles and the length w of the fibers in the second fiber set satisfy that: w/d is more than or equal to 9 and less than or equal to 200.

7. The air filter of claim 1, wherein at least one of the first and second fibers of the first collection is a composite fiber comprising a first component and a second component, the first component material having a melting point lower than the melting point of the second component material, the first component thermally bonding the fiber mat to the layer of adsorbent particles, and the first component thermally bonding the fiber mat to the nonwoven support layer.

8. The air filter of claim 7, wherein the composite fibers are of a concentric sheath-core construction, the first component encasing the second component.

9. The air filter of claim 7, wherein the material of the first component is selected from one of polyethylene and polypropylene, and the material of the second component is selected from one of polyethylene terephthalate, polypropylene terephthalate and polybutylene terephthalate.

10. The air filter according to claim 1, wherein the nonwoven fabric support layer comprises sheath-core composite fibers, and a sheath component of the sheath-core composite fibers is lower than a melting point of a core component of the sheath-core composite fibers by 20 ℃ or more; or the non-woven fabric support layer comprises low-melting-point fibers and high-melting-point fibers, and the melting point of the low-melting-point fibers is lower than that of the high-melting-point fibers by more than 20 ℃.

11. The air filter of claim 1, wherein the layer of adsorptive particles comprises active particles comprising one or more of activated carbon, ion exchange resin, zeolite, virucidal agent, biocidal agent, clay, organometallic catalyst.

12. A method of making a filter media, comprising the steps of:

s4: cooling to obtain the filter medium.

13. The method of claim 12, wherein the first and/or second layer of adsorbent particles comprises a gum powder.

14. The method of claim 12 or 13, wherein the step S1 includes preheating to 100-150 ℃, the step S2 includes preheating to 180-200 ℃, and the preheating time of S1 and S2 are both in the range of 5-10 min.

15. The method of claim 12, wherein after forming the intermediate product in S2, a third layer of sorptive particles is applied, wherein the third layer of sorptive particles includes a gum powder.

16. The method of claim 12, wherein the step of S2 is repeated a plurality of times.

17. The method for preparing a polycarbonate according to claim 12, wherein the step of Sa is provided between the steps of S2 and S3,