TW201444612A - Permeate carrier fabric for membrane filters - Google Patents

Abstract

A permeate carrier fabric includes at least some monofilament synthetic yarns to provide adequate stiffness and reduce blockage of permeate flow.

Description

Permeate carrier fabric for membrane filters [priority]

This application is part of the continuation application of the previous application No. 13/495,505, filed on June 13, 2012.

This invention relates to permeate carrier fabrics for use in membrane filters such as reverse osmosis filters, ultrafiltration filters, and other types of membrane filters. These filters are currently used for efficient liquid filtration in many applications. These membrane filters are presented in the form of spiral wound elements and are used with reverse osmosis filtration systems, microfiltration systems, nanofiltration systems, and ultrafiltration systems.

As noted above, such membrane filters typically comprise a spiral wound element made of three components: a membrane, an infiltrated carrier web, and a feed spacer. The membrane is part of the separation of the elements and may be a reverse osmosis, nanofiltration, ultrafiltration or microfiltration membrane. On the other hand, the feed spacer separates two adjacent membrane faces and acts as a spacer and turbulence promoter. The permeable carrier fabric is placed between the layers of the film and acts as a conduit that allows the permeate to flow between adjacent membranes and exit from the component. A composite consisting of a first film layer, an intermediate permeable carrier fabric, and a second film layer is formed. The three components are glued or sonic welded together on three sides, and many of the three-part composites are each glued around the perforated filter. A spacer fabric is used between the layers of the composite. The layers are wound around the core to a certain diameter based on filter size/diameter. This element is then placed in a cylindrical container.

As mentioned above, the purpose of infiltrating the carrier fabric is to provide direction and lead to the flow of the liquid. Guide the flow. It is important that the yarn in the fabric is strong enough or firm to prevent collapse.

The osmotic carrier fabric is typically a knitted polyester tricot fabric. The fabric as described above is placed between the permeable membranes. It has been found that Trikite warp knit fabric is a particularly desirable structure for supporting film materials because it has a porous knit structure and a plurality of rows of raised seams that define wrinkles between them. A long, continuous channel through which the filtered liquid flows. However, other types of fabrics can also be used as the osmotic carrier, including other types of knits or even knits. The permeable carrier fabric should have a low pressure drop (high permeability) for the osmotic flow while being able to withstand the high pressure applied by the filtered liquid without being compacted.

In the past, there have been two types of infiltrated carrier fabrics. One type of knit fabric of multifilament polyester yarns, which are subsequently coated with a resin to increase the firmness of the fabric. Another type of permeable fabric is a fabric made from a bicomponent yarn having a conventional polyester core and a low melting polyester sheath. This sheath portion of the yarn is melted during processing to impart the necessary firmness to the yarn. The resin applied to increase the firmness of the resin coated yarn also tends to partially block the fabric passage, thereby limiting a portion of the permeate flow. When the yarn in the bicomponent fabric melts, the same result occurs again and the channel is again partially blocked, thereby limiting the osmotic flow.

The inventors have subsequently determined herein that there is a need for an infiltrated carrier fabric that is sufficiently strong and strong to withstand filter pressure without collapse, while at the same time reducing the penetration of resin necessary to provide the required firmness in the past. The resulting blockage. The use of monofilament yarns in place of two-component or resin-coated multifilament yarns will reduce the resin and impart excellent firmness and improved flow to the infiltrated carrier fabric. As used herein, "monofilament" yarns are distinguished from bicomponent yarns having a core and sheath and are intended to be uncoated and sheathless single, relatively thicker filament yarns. An example is a fishing line. Since the monofilament yarn used in the infiltrated carrier fabric is sufficiently strong, it does not have to be coated or physically altered. Monofilament yarns, and therefore the permeate channels will be wider for better flow. An infiltrated carrier fabric comprising at least some monofilament polyester (or nylon) yarns will be used as the fabric between the two layers of the film. It is important that the yarn forming the channels in the fabric is sufficiently strong to withstand the filter pressure without collapse. The addition of monofilament yarns provides the necessary firmness to withstand the filter pressure conditions.

Such permeable carrier fabrics optimize the design, cost and efficiency of the finished filter. Since monofilament yarns are used in the infiltrated carrier web, less processing is required, the resulting permeate carrier fabric is more solid, less costly, and the channels in the fabric are wider, resulting in better permeate flow.

Thus, one aspect of the present invention provides an infiltrated carrier fabric comprising at least some monofilament yarn ends in a polyester or nylon and having a monofilament yarn size of at least 10 denier. The permeate carrier fabrics according to the present invention can have different warp counts, thicknesses, and weights. It can be made of (a) 100% monofilament yarn, (b) monofilament yarn and other staple fiber twisted or multifilament yarn, or (c) monofilament with some bicomponent yarns. Yarn. It is possible that the manufacturer may want to use a small amount of resin in the case of embodiment (a) or (b) to prevent the yarn from slipping or to make it easier to further process the composite or filter. However, such resins will be only a small amount of resin, which is significantly less than that used in the coating process of previous methods.

Although the permeate carrier fabric of the present invention may be knitted or woven, the preferred method is warp knitting, preferably Tricot, wherein at least one of the yarns is between 10 denier and 40 denier. Monofilament yarn. The circle and lap counts may vary based on filter performance, but the number of turns should be between at least 20 and 70 per 且 and the latitude of the latitude is between 20 and 70 latitudes per turn. . The monofilament yarn is preferably formed of polyester, but may be formed of nylon. When the fabric is made on a warp knitting machine, the machine can be a 2, 3 or 4 bar machine. The monofilament concept can exist in a range of fabrics, including (1) 100% monofilament yarns, (2) monofilament yarns and other staple fiber twisted or multifilament yarns, or (3) and bicomponent yarns. A monofilament yarn with a line, when the machine is a 2-, 3- or 4-bar machine, one or more of the rods can carry a monofilament yarn and the other rod can carry another type of yarn. When a monofilament yarn is used without a double component yarn, a small amount of resin can be added to the knitwear. A resin is provided to prevent the yarn from slipping or slipping relative to each other. The amount of resin is not sufficient to provide significant additional rigidity or support to the fabric.

Example 1

A test sample of the infiltrated carrier fabric was prepared using a combination of (1) 70 Danny 24 filament two-component polyester yarn ends and (2) 20 denier monofilament polyester yarn ends. The bicomponent yarn ends were assembled on the top rod of a 2-Pearl warp knitting machine and the monofilament yarn ends were assembled on the bottom rod of the machine. The top bar uses 2/3, 1/0 mode and the bottom bar uses 1/0, 1/2 mode. Each bundle included 1,340 yarn ends, and the final fabric target was 60 laps per turn, 50 latitudes per turn, and 3.87 ounces per square yard. The resulting fabric was divided into two 40" panels and weighed 4.16 ounces per square yard.

Example 2

A second test fabric was made using the same yarn as in Example 1, but the target of the finished fabric was a meridian count of 46 turns per turn. The resulting fabric weighed 3.23 oz/yd ² .

Example 3

A third test fabric was also prepared using the same yarn as in Example 1, but the equipment used a target cycle number of 35 turns per turn. The resulting fabric had a weight of 2.45 oz/yd ² .

Example 4

A slightly different multifilament yarn was used in the fabric for another test operation. In this example, the multifilament yarn is a 50 denier 24 filament bicomponent polyester yarn. The equipment is otherwise identical. In this example, the resulting fabric weighed 3.07 ounces per square yard.

Test 1

Perform a test in which the fabric of Example 1 is compared to a pair of 70 Danny 24 filaments A pressure test was carried out on a conventional civic knit fabric formed of a polyester and a 50 denier 24 filament two-component polyester. The 70 denier yarn head is mounted on the top pole of the Tricot warp knitting machine, which uses a 2/3, 1/0 mode and a 50 denier yarn head mounted on the bottom rod, which is used 1/0, 1/2 mode. Two fabrics were placed between adjacent reverse osmosis membranes and tested under various water pressures. The transverse permeability of the two fabrics was measured under differential pressure; and depending on the applied pressure differential, the fabric of Example 1 showed an improvement of about 30% in permeability. Both samples can effectively support the membrane.

Claims (24)

An osmotic carrier fabric for placement between adjacent membranes of a reverse osmosis, nanofiltration, ultrafiltration or microfiltration system, comprising: a) at least some monofilaments selected from the group consisting of polyester and nylon a synthetic yarn end, b) the monofilament synthetic yarn between 10 and 40 denier, c) whereby the monofilament synthetic yarn is warp knitted to form the permeate carrier fabric, the permeating carrier fabric having along the fabric a continuous passage for flowing the filtered fluid; and d) whereby the permeate carrier fabric is configured to support adjacent membranes while reducing the blockage of osmotic flow. The permeated carrier web of claim 1 wherein the permeate carrier web is substantially formed from a 100% monofilament polyester yarn. The permeate carrier fabric of claim 1 wherein the permeate carrier fabric is formed from monofilament polyester yarns and other yarns. The permeate carrier fabric of claim 1 wherein the permeate carrier fabric is formed from a monofilament polyester yarn and a bicomponent yarn. The permeate carrier fabric of claim 4, wherein the monofilament polyester yarns are 20 denier and the bicomponent yarns are 70 denier 24 filament bicomponent polyester yarn ends. The permeate carrier fabric of claim 5, further comprising a warp between 20 and 70 per turn and a weft between 20 and 70 per turn. The permeated carrier fabric of claim 1, wherein the permeate carrier fabric is a citron warp knitted fabric formed of a multifilament polyester yarn and a monofilament polyester yarn, and the monofilament polyester yarn is 20 Danny. The permeate carrier fabric of claim 7, wherein the number of turns is between about 20 and about 70 per twist and the number of latitudes is between about 20 and about 70 per ounce. A composite for use in a filter of the type used for reverse osmosis, nanofiltration, ultrafiltration or microfiltration, comprising: a) a first membrane layer and a second membrane layer; and b) supporting and separating the first a membrane layer and an infiltrated carrier fabric of the second membrane layer, the permeating carrier fabric comprising: i) at least some monofilament synthetic yarn ends selected from the group consisting of polyester and nylon, and ii) the monofilament synthetic yarns Between 10 and 40 denier, iii) whereby the monofilament synthetic yarn is warp knitted to form the permeate carrier fabric having a continuous passage along the fabric for flowing the filtered fluid; Iv) whereby the osmotic carrier fabric is configured to support adjacent membranes while reducing the blockage of osmotic flow. A filter according to claim 9 wherein the permeate carrier web is substantially formed from 100% monofilament polyester yarn. The filter of claim 9, wherein the permeate carrier fabric is formed from monofilament polyester yarns and other yarns. A filter according to claim 9, wherein the permeate carrier fabric is formed from a monofilament polyester yarn and a bicomponent yarn. The filter of claim 12, wherein the monofilament polyester yarns are 20 denier and the bicomponent yarns are 70 denier 24 filament bicomponent polyester yarn ends. The filter of claim 13, wherein the permeate carrier fabric further comprises a warp between 20 and 70 and a weft between 20 and 70 per turn. The filter of claim 9, wherein the permeate carrier fabric is a citron warp knitted fabric formed of a multifilament polyester yarn and a monofilament polyester yarn, and the monofilament polyester yarn is 20 dan Ni. The filter of claim 15 wherein the number of turns is between 20 and 70 per latitude and the weft The number of turns is between 20 and 70 per turn. A filter for reverse osmosis, nanofiltration, ultrafiltration or microfiltration, comprising: a) a composite comprising: a first membrane layer; a second membrane layer; and supporting and separating the first a membrane layer and an infiltrated carrier fabric of the second membrane layer; and b) a feed spacer disposed adjacent to the composite, wherein the composite and the feed spacer are helically wound around the core such that The feed spacer is disposed between adjacent layers of the composite, wherein the permeate carrier fabric further comprises: i) at least some monofilament synthetic yarn ends selected from the group consisting of polyester and nylon, ii) The monofilament synthetic yarn is between 10 and 40 denier, iii) whereby the monofilament synthetic yarn is warp-knitted to form the permeate carrier fabric having a continuous passage along the fabric for The filtered fluid flows; and iv) whereby the permeate carrier fabric is configured to support adjacent membranes while reducing the blockage of osmotic flow. The filter of claim 17, wherein the permeate carrier web is substantially formed from 100% monofilament polyester yarn. The filter of claim 17, wherein the permeate carrier fabric is formed from monofilament polyester yarns and other yarns. A filter according to claim 17, wherein the permeate carrier fabric is formed from a monofilament polyester yarn and a bicomponent yarn. The filter of claim 20, wherein the monofilament polyester yarns are 20 deniers and such The bicomponent yarn is a 70 denier 24 filament two component polyester yarn end. The filter of claim 21, wherein the permeate carrier fabric further comprises a warp between 20 and 70 and a weft between 20 and 70 per turn. The filter of claim 17, wherein the permeate carrier fabric is a citron warp knitted fabric formed of a multifilament polyester yarn and a monofilament polyester yarn, and the monofilament polyester yarn is 20 dan Ni. The filter of claim 23, wherein the number of turns is between about 20 and about 70 per turn and the number of wefts is between about 20 and about 70 per turn.