Fine fiber liquid particulate filter media

Abstract

A filter media for liquid particulate filtration applications is provided. The filter media includes a substrate and fine fibers, which are compressed together.

1 . A filter media for a liquid particulate filtration application, comprising:
 a substrate including coarse fibers;   fine fibers carried on the substrate, wherein the fine fibers have an average fiber diameter that is at least 4 times as small as the coarse fibers; and   wherein a basis weight of the fine fibers is at least 0.03 g/m 2  and a linear coverage of the fine fibers is at least about 5000 km/m 2 .   
     
     
         2 . The filter media of  claim 1 , wherein the filter media comprises at least two substrate layers, each substrate layer carrying the fine fibers; wherein the basis weight of the fine fibers on at least one of the substrate layer is at least 0.03 g/m 2  and the linear coverage of the fine fibers is at least about 5000 km/m 2 , and other substrate layers have a same or a different fine fiber basis weight and linear coverage than the at least one of the substrate layer. 
     
     
         3 . The filter media of  claim 1 , wherein the fine fibers are electrospun fine fibers formed by an electrospinning process, the fine fibers having an average fiber diameter of less than 0.1 micron. 
     
     
         4 . The filter media of  claim 3 , wherein the electrospun fine fibers are deposited on the substrate, wherein the fine fibers are rearranged and partially integrated with the coarse fibers by lofting and compression. 
     
     
         5 . The filter media of  claim 1 , wherein the fine fibers are at least partially integrated with the coarse fibers of the substrate; wherein the at least some fine fibers are attached to adjacent coarse fibers. 
     
     
         6 . The filter media of  claim 1 , wherein the substrate is a scrim comprising bi-component fibers, the bi-component fibers having a high melt component and a low melt component. 
     
     
         7 . The filter media of  claim 6 , wherein the bi-component fibers comprise a high melt polyester core and a low melt polyester sheath, wherein the at least one substrate and the fine fibers are heated and compressed together to form a filter media, wherein the low melt polyester sheath melts or softens to bon the coarse fibers and the fine fibers. 
     
     
         8 . The filter media of  claim 7 , wherein the fine fibers are formed of a polyamide. 
     
     
         9 . The filter media of  claim 1 , wherein the filter media comprises at least three substrate layers, each substrate layer formed of a scrim formed of bi-component coarse fibers; wherein each substrate layer carries the fine fibers; wherein each substrate layer carries the fine fibers at a basis weight of between about 0.05 g/m 2  and about 0.225 g/m 2  and a linear coverage of between about 9,000 km/m 2  and about 41,300 km/m 2 ; wherein the filter media has a total basis weight of between 0.3 g/m 2  and about 4.8 g/m 2  and a total linear coverage of between about 60,000 km/m 2  and about 300,000 km/m 2 ; wherein the substrate layers and the fine fibers are lofted by heating and compressed to form a compacted filter media configured for a liquid filtration. 
     
     
         10 . The filter media of  claim 9 , wherein the fine fibers carried on each of the substrate layers is sandwiched between two substrate layers. 
     
     
         11 . The filter media of  claim 9 , wherein the compacted filter media includes a fine fibers to fine fibers interface. 
     
     
         12 . The filter media of  claim 9 , wherein the filter media has a ISO 4406:09 cleaness code at 10% time interval of a filtration efficiency test according to ISO 16889 international standard for multi-pass method of between about 11/10/5 and 7/5/0. 
     
     
         13 . A filter element for a liquid particulate filtration application, comprising:
 a filter media, comprising:
 a substrate including coarse fibers; 
   fine fibers carried on the substrate, wherein the fine fibers have an average fiber diameter that is at least 4 times as small as the coarse fibers; and
 wherein a basis weight of the fine fibers is at least 0.03 g/m 2  and a linear coverage of the fine fibers is at least about 5000 km/m 2 ; 
   a top cap including a fluid inlet; and   a bottom cap; wherein the filter media is sealingly attached to the top cap and the bottom cap.   
     
     
         14 . The filter element of  claim 13 , wherein the filter media comprises at least three substrate layers, each substrate layer formed of a scrim formed of bi-component coarse fibers; wherein each substrate layer carries the fine fibers; wherein each substrate layer carries the fine fibers at a basis weight of between about 0.05 g/m 2  and about 0.225 g/m 2  and a linear coverage of between about 9,000 km/m 2  and about 41,300 km/m 2 ;
 wherein the filter media has a total basis weight of between 0.3 g/m 2  and about 4.8 g/m 2  and a total linear coverage of between about 60,000 km/m 2  and about 300,000 km/m 2 ; wherein the substrate layers and the fine fibers are lofted by heating and compressed to form a compacted filter media configured for a liquid filtration.   
     
     
         15 . The filter element of  claim 14 , wherein the fine fibers are formed of a polyamide and have an average fiber diameter of less than 0.1 micron; wherein the bi-component coarse fibers include a high melt polyester core and a low melt polyester sheath; wherein the compacted filter media includes at least some fine fibers embedded in the low melt polyester sheath. 
     
     
         16 . The filter element of  claim 13 , wherein the filter media is pleated, and the pleated filter media is sealingly attached to the top cap and the bottom cap by thermal plastic welding. 
     
     
         17 . The filter element of  claim 16 , wherein the thermal plastic welding attachment of the pleated filter media to the top and bottom caps prevents a liquid stream from bypassing the pleated filter media. 
     
     
         18 . A method of forming a filter media, comprising:
 electrostatically spinning fine fibers having an average fiber diameter of less than 1 micron;   applying the fine fibers on a substrate to provide a fine fiber basis weight of at least 0.03 g/m 2  and a linear coverage of the fine fibers of at least about 5000 km/m 2 , wherein the substrate comprising coarse fibers having an average fiber diameter that is at least 4 times larger than the fine fibers; and   processing the substrate with the applied fine fibers to rearrange the fine fibers on the substrate.   
     
     
         19 . The method of  claim 18 , wherein rearrangement of the fine fibers on the substrate includes lofting the substrate and the fine fibers by heating, and compacting the substrate and the fine fibers via a set of rollers. 
     
     
         20 . The method of  claim 18 , further comprising:
 providing at least two substrate layers, wherein each substrate layer is formed of a scrim comprising bi-component coarse fibers;   applying the fine fibers on a first substrate layer to provide a fine fiber basis weight of between about 0.05 g/m 2  and about 0.225 g/m 2  and a linear coverage of between about 9,000 km/m 2  and about 41,300 km/m 2 ;   applying the fine fibers on a second substrate layer to provide a fine fiber basis weight of between about 0.05 g/m 2  and about 0.225 g/m 2  and a linear coverage of between about 9,000 km/m 2  and about 41,300 km/m 2 ;   laminating the first substrate layer carrying the fine fibers and the second substrate layer carrying the fine fibers; and   compressing the first and second substrate layers and the fine fibers to form a compressed filter media configured for a liquid filtration.   
     
     
         21 . The method of  claim 20  further including lofting the first and second substrate layers and the fine fibers prior to compressing to rearrange the fine fibers and to at least partially integrate the fine fibers with the coarse fibers of the substrate. 
     
     
         22 . The method of  claim 20 , wherein applying the fine fibers such that the basis weight and the linear coverage of the fine fibers on the first substrate is greater than that of the second substrate layer. 
     
     
         23 . The method of  claim 20 , wherein applying the fine fibers such that the basis weight and the linear coverage of the fine fibers on the first substrate layer is equal to that of the second substrate layer. 
     
     
         24 . The method of  claim 18 , wherein electrostatically spinning fine fibers include forming the fine fibers from a solution including a polyamide. 
     
     
         25 . The method of  claim 18 , further including pleating the filter media. 
     
     
         26 . A method of filtering a liquid, comprising:
 providing the filter media of  claim 1 ; and   flowing a liquid stream through a filter media to capture particulates in the liquid stream.   
     
     
         27 . A filter media for a liquid particulate filtration application, comprising:
 a substrate including bi-component coarse fibers having an average fiber diameter of greater than 0.6 micron;   fine fibers carried on the substrate, the fine fibers having an average fiber diameter of less than 0.6 micron, wherein the average diameter of the coarse fibers is at least 4 times larger than the average fiber diameter of the fine fibers; and   wherein a basis weight of the fine fibers is at least 0.03 g/m 2  and a linear coverage of the fine fibers is at least about 5000 km/m 2 .   
     
     
         28 . A filter media for a liquid particulate filtration application, comprising:
 at least two layers of substrate, each of the substrate layers formed of coarse fibers;   fine fibers carried on each of the substrate layers, wherein an average fiber diameter of the coarse fibers is at least 4 times larger than an average fiber diameter of the fine fibers; and   wherein a basis weight of the fine fibers on at least one substrate layer is at least 0.03 g/m 2  which provides a linear fiber coverage of at least about 5000 km/m 2 .