CZ244191A3 - needled filter cloth - Google Patents

Abstract

The fabric is designed for rta hose and pocket filters industrial air filtration hot 90 ° C to 260 ° C. It consists of a supporting fabric on which at least one synthetic fiber fleece is embossed on at least one side thereof. The novelty of the invention is that the fabric for the yarn filter has a warp of silk, whereas the weave is made of synthetic yarns, while the fabric for the pouch filters is the opposite, the weft is of glass silk and the warp is of synthetic yarn. These synthetic yarns and routine fibers are made of a material 9 at least a portion of a temperature range of between 90 ° C and 260 ° C, such as polypropylene, polyester, polyacrylonitrile, polyphenene sulfide, polyimide and polytetrafluoroethylene.

Description

(57) The fabric is intended for rta hose and pocket filters for industrial air filtration at temperatures between 90 ° C and 260 ° C. It consists of a carrier fabric on which at least one side is a needled synthetic fiber web. The novelty of the invention is that the fabric for the hose filter has a warp of glass silk, while the weft is made of synthetic threads, while the fabric for the pocket filter is the opposite, the weft is of glass silk and the warp is of synthetic threads. These synthetic threads and routine fibers are made of a material that can withstand at least a portion of the temperature range between 90 ° C and 260 ° C, such as polypropylene, polyester, polyacrylonitrile, polyphenylene sulfide, polyimide and polytetrafluoroethylene.

-1Punched filter fabric

Technical field

The invention relates to needlepunched filter fabrics intended for hose and pocket filters, in particular large capacity filters for industrial filtration of air temperatures up to 260 ° C, in particular 90 ° C to 260 ° C. The fabric consists of a woven fabric, at least one side of which is covered with a fibrous web secured thereto by a plurality of binding webs, evenly distributed over the entire surface of the fabric and formed from some nonwoven fibers extending over a portion of its length to the opposite side of the carrier fabric. The fleece consists of synthetic fibers which, in conjunction with the carrier fabric, withstand at least part of the temperature range between 90 ° C and 260 ° 0. Optionally, the fabric is thermally precipitated and at least portions of the nonwoven fibers at least on one surface of the fabric are melted to molten. One surface of the fabric is smooth and forms the inlet side in the hose and pocket filters.

BACKGROUND OF THE INVENTION

Needle fabric is known from the United States, which is suitable for the manufacture of large-capacity filter hoses for temperatures above 150 ° C. The fabric consists of a polytetrafluoroethylene carrier fabric into which a nonwoven web consisting of 85 wt.% To 90 wt.% Polytetrafluoroethylene fibers and 15 wt. % to 10 wt.% fine glass fibers. On the filter side, it may not be possible to find a disadvantage of this fabric, but this is not the case in other aspects. The first disadvantage is the high purchase price, which is recognized by the textile manufacturer himself. Polytetrafluoroethylene staple fibers are expensive and the polytetrafluoroethylene silk threads required to produce the carrier fabric are approximately three times more expensive than the staple fibers. A second disadvantage is the use of glass staple fibers in the blend of nonwoven fibers. Both the fleece formation and the needling process generate dust, especially from brittle glass fibers. Glass dust complicates production after the health 3 pages. Finally, the third disadvantage is a carrier fabric made up of synthetic fibers only, which, under mechanical stress, which occurs during periodic regeneration of the filtering

The tubing exhibits a higher, undesirable elongation in both the longitudinal and transverse directions of the carrier fabric.

From the description of the invention according to cf. AO No. 267 733 discloses a large-capacity filter hose made of a needled fabric consisting of a glass carrier fabric, one side of which in the filter hose is the inlet side is a needled synthetic fiber web with at least part of the temperature range between 150 ° C and 260 ° C Deň: 32 ° C. Both surfaces of the needled fabric are melted. While this fabric overcomes the three disadvantages of the prior needlepunch fabric described above and exhibits negligibly low elongation when used in a large capacity industrial filter, it lacks transverse elasticity in the hose filter cartridge and the pocket insert lacks elasticity in the longitudinal direction. The lack of elasticity does not allow both the needling of the needle-punched fabric to be increased and thus to increase the firmness of the non-woven attachment in the carrier fabric and, secondly, to improve the regeneration of the filter element which is to be elastically vibrated.

SUMMARY OF THE INVENTION

The above-described disadvantages are eliminated by needlepunched filter fabric for hose and pocket filters, especially large capacity filters for industrial air filtration at temperatures up to 260 ° C, in particular 90 ° G to 260 ° C, consisting of a carrier fabric whose at least one side is covered with a fiber fleece affixed thereto by a plurality of binding sites uniformly distributed throughout the fabric and formed from some non-woven fibers extending over a portion of its length to the opposite side of the carrier fabric, and the web consists of ee synthetic fibers which endure at least a temperature range between 90 ° 0 and 260 ° 0, whereby the fabric is optionally still thermally precipitated and at least portions of the nonwoven fibers at least on one surface of the fabric are melted to molten and one surface of the fabric is smooth and forms an inlet side in a hose or pocket filter The essence and novelty of the needled filter fabric according to the invention consists in that the carrier fabric formed from two mutually intersecting and interlocking thread systems consists in one system of glass silk threads and

In a second set of yarns of synthetic fibers selected from the group consisting of polypropylene, polyacrylonitrile, polyester, aramid, polyphenylene sulfide, polyphenylene oxide, polyoxadiazole and polytetrafluoroethylene fibers, the fiber web being formed of at least one kind of synthetic fibers, also selected from the aforementioned fiber group . The carrier fabric in the needled filter fabric for hose filters comprises glass silk in a warp yarn system, while the carrier fabric in the needled filter fabric for pocket filters comprises glass silk in a weft yarn system. The needle-punched filter fabric preferably has a thickness of between 1.7 mm and 2.7 µm, in particular a weight of 400 g / m ² _and 600 g / m ² , of which the carrier fabric usually comprises 120 g / m ² to 200 g / m ² .

The main advantage of the invention is a new embodiment of the carrier fabric in which one set of threads consists of glass silk and the other set of threads consists of synthetic yarns. Glass silk gives the needled filter fabric both high strength, above 1000 N, as well as slight ductility, about 2 in the glass silk bearing direction. Synthetic threads provide the necessary elasticity for the needled filter fabric, expressed in elongation at break of about 40%, in the direction of placement of the synthetic threads.

DETAILED DESCRIPTION OF THE INVENTION

The advantages of the invention will become more apparent from the description of exemplary embodiments thereof that do not require a drawing.

Example 1

The needled filter fabric, suitable for the production of a large capacity filter hose of the required length and diameter and intended for industrial air filtration up to 150 ° C, is produced as follows:

A carrier fabric weighing 150 g / m @ 2 is woven in a weave of plain linen with 680 dtex glass silk and 500 dtex polyester silk weft yarn.

b) A fiber web of 150 g / m 2 is made up of a blend of polyester staple fibers, consisting of 50 wt.% fibers of 1.7 dtex and 38 mm length and 50 wt.% fibers of 4 to 4 dtex and length. 6 5 mm. The web has a fiber orientation predominantly ^t. However, a web with a random fiber orientation may also be used.

c) A fibrous web is pierced into the carrier fabric, each with an intensity of 150 inches / cm @ 2, so that the resulting three-layer blank comprises 300 punctures / cm @ 2. The so-called oriented needles are used in which the top of the triangular working part facing the glass warp of the carrier fabric is free of barbs and has two barbs at the two edges of the working part, thereby preventing serious damage to the glass silk. The binder bundles formed during the stitching at the binding sites bind the fleece to the carrier fabric and at the same time prevent the movement of threads in the fabric. The fiber fleece not only protects the glass silk in the fabric from abrasion, but also contributes to filtration.

d / Then, the needlepunch is thermally fixed on an ARTOS type precipitation machine at a temperature of about 170 ° C for about 4 minutes, thereby improving the anchoring of the fibrous webs in the carrier fabric and enhancing the filtering effect of the fabric.

e) Radiant heat melting follows, which is carried out on the melting apparatus in a manner known from the description of the invention in accordance with U.S. Pat. No. 149,546. The needled fabric is slightly melted on the surface forming the outlet side during filtration, while the other side, which forms the inlet side, is intensely melted and smoothed immediately after melting by passing between the rolls.

f / The needlepunched filter fabric thus produced exhibits properties that are around the following values:

-ΊWeight ................................ 500 g / m ^ thickness ........ .......................... 1,9 mm longitudinal tensile strength ........... 1000 N

- ^ft - transverse direction ............ 750 N elongation at break in longitudinal direction ...... 2% in transverse direction ....... 55% breathability ... ............................. 550 l / m ² / s

oil mist method / Μ0Μ / .. 20 $ powder method Spongelit /M?S/.·. 99.9996% pressure drop with Μ0Μ ................. 12 Pa using MPS ................. 575 Pa dimensional stability for 2 hours:

at a temperature of 150 ° 0 in the longitudinal direction ........... 0,0 /

- in the transverse direction ............- 1,65 1

Example 2

The needled filter fabric, suitable for making a pocket filter cartridge for large capacity filters for industrial air filtration up to 140 ° C, is produced by the procedure of Example 1, but with the following changes in the material used in its apparatus.

a) Support fabric - weight 200 g / m ² ; weave: spun twill; warp: polyacrylonitrile yarn 140 dtex; weft: glass silk 500 dtex;

b / Fibrous web - weight: 170 g / m /; composition: high strength polyacrylonitrile staple fineness 2.8 dtex and length 60 mm.

c / Needling - fiber fleece on both sides of the carrier fabric; Injection Rate: 120 injections / cm ² from each side; needles: oriented, the top of the triangular working part without the barbed and on one edge of the working part there is one barb to prevent damage to the glass thread.

d / Thermal fixation is not performed because the high-strength polyacrylonitrile fibers have been sufficiently elongated in their manufacture.

/ -0e / Fusing - both sides, one of which, which serves as the inlet side during filtration, is smoothed immediately after melting. The outlet side melts more slightly than the inlet side.

f / The needle punched filter fabric produced is around the values given below.

weight ................................. 600 g / m ² thickness .......... ........... 2,7 mm longitudinal tensile strength .......... 800 N

- - in transverse direction ........... 1200 N elongation at break in longitudinal direction ..... 45 $ in transverse direction ...... 10% breathability ....... ........................ 100 l / m ² / s separation determined by MOM ........... 56 by MPS. ...... 99.9999% pressure drop detected by MOM ....... 56 Ta by MPS ....... 525 Pa dimensional stability for 2 hours:

at 140 ° C in longitudinal direction ........ 4 · 4,8 in transverse direction ........- $ 1.0

Example 5

Needled filter fabric suitable for making a hose jet filter, an industrial filter that is regenerated by a compressed air blower. A fabric capable of filtering air to a temperature of up to 260 ° C was prepared as in Example 1, but with the following changes.

a / Support fabric - weight: 180 g / m ² ; warp: glass silk 1400 dtex; weft: polyimide yarn 200 dtex;

b / Fiber fleece - weight 170 g / m ² ; composition: polyimide staple fineness 2.2 dtex and length 50 mm, c / Needling - fiber fleece on both sides of the carrier fabric; needling intensity 240 punctures / cm ² from each side.

-Ίά / Thermal fixation - no need.

e / Fusing - only the inlet side is fused and immediately smoothed by the passage between the rollers.

f / The properties of the needlepunched filter fabric are around the values given below.

weight .................................... 550 g / m ² thickness ....... ............................. 2,6 mm longitudinal tensile strength ......... 2000 N

- in the transverse direction .............. 1000 N elongation at break in the longitudinal direction ...... 2 / in the transverse direction ......... 4-0% air permeability ................... 300 l / m2 / s separation determined by pomocí0Μ .............. 26%

- with MPS .............. 99,995 $ pressure drop detected with MOLI ....... 13 Pa

- ^{, r} - using MPS ....... 333 Pa dimensional stability for 2 hours:

at 260 ° 0 in the longitudinal direction ........ 40.14% in the transverse direction ........... -0.5 $

Example 4

The needled filter fabric, suitable for producing a high-efficiency filter, in particular a hose filter, for industrial air filtration up to 230 ° C, is prepared according to the procedure of Example 1, but with the following changes.

a) Support fabric - weight 150 g / m2; weave twill warp: glass silk 680 dtex; weft: polyphenylene sulfide yarn 250 dtex.

b / Fiber fleece - weight 270 g / m ² ; composition: polyphenylene sulphide staple - in a mixture of 50 wt.

8c / Needling - fiber fleece on only one side of the woven fabric; stitching intensity: 180 stitches / ⁰¹¹¹ ^ from the fleece side.

d / Thermal fixation - thermofusion device TRA, temperature 230 ° 0 for 1 min. Thermal fixation can be omitted for fabrics for air filtration below 190 ° C.

e / Melting - the inlet side is melted and smoothed. The inlet side is a fibrous web. The outlet side 3e only melts slightly to improve the bonding of the web to the carrier fabric, sealing portions of the fibers pulled from the web onto the opposite surface of the carrier fabric.

f / The properties of the needlepunched‘filtration fabric are around the following values:

weight ......................... 450 g / m ^ thickness .................. .............. 1.3 mm longitudinal tensile strength ............ 1000 N in transverse direction ......... .... 1500 N tensile strength in the longitudinal direction ....... 2% in the transverse direction ........ 40% breathability ............... .................. 350 l / m ^ / s separation determined by MOM ............. 20% by MPS .... ......... 99 999999% pressure drop detected by MOM ......... 15 Pa using MPS ......... 300 Pa dimensional stability for 2 hours:

at a temperature of 230 ° C in the longitudinal direction ....... 40.14%

- in the transverse direction .......- 1,6%

The examples given do not exhaust all the possibilities offered by the claims. The backing fabric has in all examples synthetic threads of the same chemical composition as the fibers of the web covering at least one side of the backing fabric. However, this is not necessary. They may be of a different chemical composition, provided that the different type resists the temperature of the filtered air.

- Q—

The fibrous web may comprise an admixture of other fibers, provided that the mechanical or filter properties of the web are not impaired. For example, it is preferable to add polyester fibers to the polyacrylonitrile fibers to increase the abrasion resistance of the web. For air temperatures up to 90 ° 0, polypropylene is sufficient for both the synthetic threads in the fabric and the fibrous web. The addition of polyacrylonitrile fibers to the polypropylene fibers increases the temperature resistance of the web from 90 ° to 110 ° C. In forming fiber mixtures, account shall be taken of the heat resistance, which is as follows for each fiber type:

polypropylene ........... 90 ° C polyacrylonitrile ........... 130 ° 0 polyester ......... ............. 150 ° C ar amide .............. 180 ° C polyphenylene sulphide ............. 190 ° C polyphenylene oxide ............... 190 ° C polyimide ...................... 260 ° C polyoxadiazole ... .............. 250 ° C polytetrafluoroethylene .......... 260 ° C.

Claims (3)

PATENT REQUIREMENTS -o> π o <o ca and> <-> c r- <m N · < O cn • r 1. Needled filter fabric, intended for hose and pocket filters, in particular large capacity filters for industrial air filtration at temperatures of up to 260 ° C, in particular 90 ° C to 260 ° C, consisting of a carrier fabric at least one side of which is covered with a fiber fleece attached to A plurality of binding sites, uniformly distributed throughout the fabric and formed from some non-woven fibers extending over a portion of its length to the opposite side of the backing fabric, and the web consists of synthetic fibers that tolerate at least a temperature range between 90 °. and 260 ° C, wherein the fabric is optionally still thermally precipitated and at least portions of the nonwoven fibers at least on one surface of the fabric are melted to molten and one surface of the fabric is smooth and forms an inlet side in both the hose and pocket filters, nasná tkani The nail formed of two intersecting and interlocking yarns consists in one set of glass silk yarns and in the other set of synthetic fiber yarns selected from the group consisting of polypropylene, polyacrylonitrile, polyester, aramid, polyphenylene sulphide, polyphenylene oxide, polyoxadiazole fibers , polyamide and polytetrafluoroethylene, wherein the fibrous web is formed from at least one kind of synthetic fibers, also selected from the aforementioned group of fibers. Needled filter fabric according to claim 1, characterized in that: characterized in that the carrier fabric for the production of needlepunched filter fabrics for hose filters comprises glass silk in a set of threads forming the warp. Needle filter fabric according to claim 1, characterized in that the carrier fabric in the needlestick filter fabric for pocket filters comprises glass silk in a set of weft yarns. -114. Needled filter fabric according to claim 1, characterized in that the carrier fabric has a weight of 120 g / m ² and 200 g / m ² . Needle filter fabric according to claim 1, characterized in that it has a weight of 400 g / m ² to 600 g / m ² and a thickness of 1.7 nm to 2.7 mm.