# US 2019/0314747 A1 · Pre-coalescing multi-layered filter media > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2019/0314747 A1 - Document ID: US20190314747A1 - Status: Published application - Kind: A1 - Application number: 16/359,546 - Filed: 2019-03-20 - Published: 2019-10-17 - Earliest claimed: 2012-11-13 - Assignees: Hollingsworth & Vose Company - Applicants: Hollingsworth & Vose Company - Inventors: Máté Nagy; Siqiang Zhu - Web page: https://patentgrep.com/patent/US20190314747A1 ## CPC - B01D 39/18: the material being cellulose or derivatives thereof ({cork or peat B01D39/1646} ; making filter paper D21F11/14) - B01D 39/1607: {the material being fibrous (B01D39/18 takes precedence)} - B01D 39/1615: {of natural origin} - B01D 39/1623: {of synthetic origin} - B01D 39/2017: {the material being filamentary or fibrous} - B01D 2239/025: comprising nanofibres - B01D 2239/0414: Surface modifiers, e.g. comprising ion exchange groups - B01D 2239/0622: Melt-blown - B01D 2239/065: More than one layer present in the filtering material - B01D 2239/0654: Support layers - B01D 2239/1233: Fibre diameter - B01D 2275/10: Multiple layers - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) ## Abstract Fiber webs that may be used as filter media are provided. In some embodiments, the filter media may include multiple layers. Each layer may be designed to have separate functions in the filter media. For example, a first layer may be provided for improving dust holding capacity, a second layer for improving efficiency, and a third layer for providing support and strength to the media. By designing the layers to have separate functions, each layer may be optimized to enhance its function without negatively impacting the performance of another layer of the media. ## Claims ### Claim 1 (canceled) ### Claim 2 A filter media, comprising: a first layer comprising a first plurality of fibers, wherein the first plurality of fibers comprises synthetic fibers, and wherein the first layer has a first air permeability and a first mean flow pore size; a second layer comprising a second plurality of fibers, wherein the second plurality of fibers comprises synthetic fibers, and wherein the second layer has a second air permeability and a second mean flow pore size; and a third layer comprising a third plurality of fibers, wherein the third plurality of fibers comprises synthetic fibers and/or cellulose fibers, and wherein the third layer has a third air permeability and a third mean flow pore size; wherein each of the first and third air permeabilities is higher than the second air permeability and/or wherein each of the first and third mean flow pore sizes is higher than the second mean flow pore size; wherein the second layer is positioned between the first and third layers; wherein the filter media has an efficiency for 4 micron or larger particles of greater than or equal to about 90% measured according to standard ISO 19438; and wherein the filter media has an initial efficiency for 4 micron or larger particles of greater than or equal to about 80% measured according to standard ISO 19438. ### Claim 3 (depends on 2) The filter media of claim 2, wherein the third plurality of fibers comprises cellulose fibers. ### Claim 4 (depends on 2) The filter media of claim 2, wherein the synthetic fibers of the second plurality of fibers comprise fibrillated fibers. ### Claim 5 (depends on 2) The filter media of claim 2, wherein the synthetic fibers of the first plurality of fibers comprise polyester fibers. ### Claim 6 (depends on 2) The filter media of claim 2, wherein the third layer comprises an additive. ### Claim 7 (depends on 2) The filter media of claim 2, wherein the first layer, the second layer, and the third layer are discrete layers. ### Claim 8 (depends on 2) The filter media of claim 2, wherein the first layer, the second layer, and the third layer are discrete layers; wherein the synthetic fibers of the first plurality of fibers comprise polyester fibers; wherein the synthetic fibers of the second plurality of fibers comprise fibrillated fibers; wherein the third plurality of fibers comprises cellulose fibers; and wherein the third layer comprises an additive. ### Claim 9 (depends on 2) The filter media of claim 2, wherein a surface of at least one layer is modified to be hydrophilic or hydrophobic. ### Claim 10 (depends on 2) The filter media of claim 2, wherein the third plurality of fibers comprises synthetic fibers. ### Claim 11 (depends on 2) The filter media of claim 2, wherein the first layer and/or second layer contain 0% cellulose. ### Claim 12 (depends on 2) The filter media of claim 2, wherein the first layer contains 0% cellulose. ### Claim 13 (depends on 2) The filter media of claim 2, wherein the filter media has an efficiency for 1 micron or larger particles of greater than or equal to about 90% measured according to standard ISO 19438. ### Claim 14 (depends on 2) The filter media of claim 2, wherein the first layer, second layer, and/or third layer contain 0% glass. ### Claim 15 (depends on 2) The filter media of claim 2, wherein the third layer contains 0% glass. ### Claim 16 A filter media, comprising: a first layer comprising a first plurality of fibers, wherein the first layer has a first air permeability and a first mean flow pore size; a second layer comprising a second plurality of fibers, wherein the second layer is a non-wet laid layer, and wherein the second layer has a second air permeability and a second mean flow pore size; and a third layer comprising a third plurality of fibers, wherein the third layer has a third air permeability and a third mean flow pore size; wherein the first layer and/or the third layer comprise cellulose; wherein the second layer is positioned between the first and third layers; wherein the filter media has an efficiency for 4 micron or larger particles of greater than or equal to about 90% measured according to standard ISO 19438; and wherein the filter media has an initial efficiency for 4 micron or larger particles of greater than or equal to about 80% measured according to standard ISO 19438. ### Claim 17 (depends on 16) The filter media of claim 16, wherein the second plurality of fibers comprises meltblown fibers, meltspun fibers, melt electrospun fibers, solvent electrospun fibers, and/or centrifugal spun fibers. ### Claim 18 (depends on 16) The filter media of claim 16, wherein the cellulose comprises lyocell. ### Claim 19 (depends on 16) The filter media of claim 16, wherein the filter media has an efficiency for 1 micron or larger particles of greater than or equal to about 90% measured according to standard ISO 19438. ### Claim 20 (depends on 16) The filter media of claim 16, wherein the third layer comprises cellulose. ### Claim 21 (depends on 16) The filter media of claim 16, wherein a surface of at least one layer is modified to be hydrophilic or hydrophobic. ### Claim 22 (depends on 16) The filter media of claim 16, wherein each of the first and third air permeabilities is higher than the second air permeability and/or wherein each of the first and third mean flow pore sizes is higher than the second mean flow pore size.